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bm p280 : data sheet document revision 1 . 1 2 document release date july 11 th , 201 4 document number bst - bm p280 - ds00 1 - 10 technical reference code(s) 0 273 300 354 notes data in this document are subject to change without notice. product photos and pictures are for illustration purposes only and may differ from the real products appearance. d ata sheet BMP280 digital p ressure s ensor bosch sensortec
datasheet BMP280 digital pressure sensor page 2 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. bm p28 0 d igital p ressure s ensor key parameters ? pressure range 300 1100 hpa ( equiv . to +9000 - 500 m above/below sea level) ? package 8 - pin lga metal - lid f ootprint : 2.0 2.5 mm2 , h eight : 0.95 mm ? relative accuracy 0.12 hpa , equiv. to 1 m ( 950 1050hpa @25c ) ? a bsolute accuracy typ. 1 hpa ( 950 ... 1050 hpa , 0 ... +40 c ) ? temperature coefficient offset 1.5 pa/k , equiv. to 12 . 6 cm/k (25 ... 40c @900hpa) ? digital interfaces i2c (up to 3.4 mhz) spi (3 and 4 wire, up to 10 mhz) ? current consum ption 2.7 a @ 1 hz sampling rate ? temperature range - 40 +85 c ? rohs compliant, halogen - free ? msl 1 typical applications ? enhancement of gps navigation ( e.g. time - to - first - fix improvement, dead - reckoning, slope detection ) ? in door navigation (floor detection, elevator detection) ? outdoor navigation, l eisure and sports applications ? weather forecast ? health care applications (e.g. spirometry) ? vertical velocity indication ( e.g. rise/sink speed ) target devices ? handsets such as mobile phones, table t pcs, gps devices ? navigation systems ? portable health care devices ? home w e a ther stations ? flying toys ? watches
datasheet BMP280 digital pressure sensor page 3 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. general description robert bosch is the world market leader for pressure sensors in automotive and consumer applications. boschs proprietary apsm ( a dvanced p orous s ilicon m embrane ) mems manufacturing process is fully cmos compatible and allows a hermetic sealing of the cavity in an all silicon process . the BMP280 is based on boschs proven p iezo - resistive pressure sensor technology featuring hi gh emc robustness, high accuracy and linearity and long term stability. the BMP280 is an absolute barometric pressure sensor especially designed for mobile applications. the sensor module is housed in an extremely compact 8 - pin metal - lid lga package with a footprint of onl y 2.0 2.5 mm 2 and 0.95 mm package height. its small dimensions and i ts low power consumption of 2 . 7 a @1hz allow the implementation in battery driven devices such as mobile phones, gps modules or watches. as the successor to the widely adopted bmp180, the BMP280 delivers high performance in all application s that require precise pressu r e measurement. the BMP280 operates at lower noise, supports new filter modes and an spi interface within a footprint 63% smaller than the bmp180 . the emerging applications of in - door navigation, health care as well as gps refinement require a high relative accuracy and a low tco at the same time . bmp180 and BMP280 are perfectly suitable for applications like floor detection since both sensors feature excellent relative accuracy is 0.12 hpa, which is equivalent to 1 m difference in altitude . the very low o ffset temperature coefficient (tco) of 1.5 pa/k translates to a temperature drift of only 12.6 cm/k. please contact you r regional bosch sensortec partner f or more information about software packages enhancing the calculation of the altitude given by the BMP280 pressure reading . table 1 : c omparison between bmp180 and BMP280 parameter bmp180 BMP280 footprint 3.6 3. 8 mm 2.0 2.5 mm minimum v dd 1.80 v 1.71 v minimum v ddio 1.62 v 1.20 v current consumption @ 3 pa rms noise 12 a 2.7 a rms noise 3 pa 1.3 pa pressure resolution 1 pa 0.18 pa temperature resolution 0.1c 0.01c interfaces i2c i2c & spi (3 and 4 wire, mode 00 and 11) measurement modes only p or t, forced p&t, forced or periodic measurement rate up to 120 hz up to 157 hz filter options none five bandwidths
datasheet BMP280 digital pressure sensor page 4 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. index of contents 1. specification ................................ ................................ ................................ ........................ 7 2. absolute maximum ratings ................................ ................................ ............................ 9 3. functional descri ption ................................ ................................ ................................ . 10 3.1 b lock diagram ................................ ................................ ................................ ............... 11 3.2 p ower management ................................ ................................ ................................ ....... 11 3.3 m easurement flow ................................ ................................ ................................ ....... 11 3.3.1 p ressu re measurement ................................ ................................ ................................ ........... 12 3.3.2 t emperature measureme nt ................................ ................................ ................................ ..... 13 3.3.3 iir filter ................................ ................................ ................................ ................................ .... 13 3.4 f ilter selection ................................ ................................ ................................ ............ 14 3.5 n oise ................................ ................................ ................................ .............................. 15 3.6 p ower modes ................................ ................................ ................................ ................. 15 3.6.1 s leep mode ................................ ................................ ................................ ................................ 16 3.6.2 f orced mode ................................ ................................ ................................ ............................. 16 3.6.3 n ormal m ode ................................ ................................ ................................ ............................. 16 3.6.4 m ode transition diagr am ................................ ................................ ................................ ......... 17 3.7 c urrent consumption ................................ ................................ ................................ ... 18 3.8 m easurement timings ................................ ................................ ................................ .... 18 3.8.1 m e asurement time ................................ ................................ ................................ .................... 18 3.8.2 m easurement rate in n ormal mode ................................ ................................ ......................... 19 3.9 d ata readout ................................ ................................ ................................ ................ 19 3.10 d ata register shadowi ng ................................ ................................ ........................... 20 3.11 o utput compensation ................................ ................................ ................................ . 20 3.11.1 c omputational require ments ................................ ................................ ............................... 20 3.11.2 t rimming parameter re adout ................................ ................................ ................................ 21 3.11.3 c ompensation formula ................................ ................................ ................................ .......... 21 3.12 c alculating pressure and temperature ................................ ................................ ... 22 4. global memory map and register descrip tion ................................ .................. 24 4.1 g eneral remarks ................................ ................................ ................................ .......... 24 4.2 m emory m ap ................................ ................................ ................................ ................... 24 4.3 r egister description ................................ ................................ ................................ .... 24 4.3.1 r egister 0 x d0 id ................................ ................................ ................................ .................... 24 4.3.2 r egister 0 x e0 reset ................................ ................................ ................................ .............. 24 4.3. 3 r egister 0 x f3 status ................................ ................................ ................................ ............ 25 4.3.4 r egister 0 x f4 ctrl _ meas ................................ ................................ ................................ ...... 25 4.3.5 r egister 0 x f5 config ................................ ................................ ................................ ............ 26 4.3.6 r egister 0 x f70 x f9 press (_ msb , _ lsb , _ xlsb ) ................................ ................................ .. 26 4.3.7 r egister 0 x fa0 x fc temp (_ msb , _ lsb , _ xlsb ) ................................ ................................ ... 27
datasheet BMP280 digital pressure sensor page 5 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 5. digital interface s ................................ ................................ ................................ ............ 28 5.1 i nterface selection ................................ ................................ ................................ ...... 28 5.2 i2c i nterface ................................ ................................ ................................ .................. 28 5.2.1 i2c writ e ................................ ................................ ................................ ................................ .... 29 5.2.2 i2c read ................................ ................................ ................................ ................................ ..... 29 5.3 spi interface ................................ ................................ ................................ ................. 30 5.3.1 spi write ................................ ................................ ................................ ................................ ... 31 5.3.2 spi read ................................ ................................ ................................ ................................ .... 31 5.4 i nterface parameter s pecification ................................ ................................ ............. 32 5.4.1 g eneral interface par ameters ................................ ................................ ............................... 32 5.4.2 i2c timings ................................ ................................ ................................ ................................ . 32 5.4.3 spi timi ngs ................................ ................................ ................................ ................................ 33 6. pin - out and connection d iagram ................................ ................................ ............... 35 6.1 p in - out ................................ ................................ ................................ ........................... 35 6.2 c onnection diagram 4 - wire spi ................................ ................................ ................... 36 6.3 c onnection diagram 3 - wire spi ................................ ................................ ................... 37 6.4 c onnection diagram i 2 c ................................ ................................ ................................ 38 7. package, reel and environment ................................ ................................ ................ 39 7.1 o utline dimensions ................................ ................................ ................................ ....... 39 7.2 l andin g pattern recommenda tion ................................ ................................ ............... 40 7.3 m arking ................................ ................................ ................................ .......................... 41 7.3.1 m ass production devic es ................................ ................................ ................................ ........ 41 7.3.2 e ngineering samples ................................ ................................ ................................ ................ 41 7.4 s o ldering guidelines ................................ ................................ ................................ .... 42 7.5 t ape and reel specifi cation ................................ ................................ ......................... 43 7.5.1 d imensions ................................ ................................ ................................ ................................ 43 7.5.2 o rientation within th e reel ................................ ................................ ................................ ..... 43 7.6 m ounting and assembly recommendations ................................ ................................ . 44 7.7 e nvironmental safety ................................ ................................ ................................ .. 44 7.7.1 r o hs ................................ ................................ ................................ ................................ ......... 44 7.7.2 h alogen content ................................ ................................ ................................ ..................... 44 7.7.3 i nte rnal package structu re ................................ ................................ ................................ ... 44 8. appendix 1: compu tation formulae for 32 bit systems ................................ .. 44 8.1 c ompensation formula in floating point ................................ ................................ .... 44 8.2 c ompensation formula in 32 bit fixed point ................................ ................................ 45 9. legal disclaimer ................................ ................................ ................................ ............... 47 9.1 e ngineering samples ................................ ................................ ................................ .... 47
datasheet BMP280 digital pressure sensor page 6 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 9.2 p roduct use ................................ ................................ ................................ .................. 47 9.3 a pplication examples and hints ................................ ................................ ................... 47 10. document history and modification ................................ ................................ ..... 48
datasheet BMP280 digital pressure sensor page 7 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 1. specification if not stated otherwise, ? all values are valid over the full voltage range ? all minimum/maximum values are given for the full accuracy temperature range ? minimum/maximum values of drifts, offsets and temperature coefficients are 3 ? values over lifetime ? typical values of currents and state machine timings are determined at 25 c ? minimum/maximum values of currents are determined using corner lots over complete temperature range ? minimum/maximum values of state machine timings are determined using corner lots over 0+65 c temperature range the specification tables are split into pressure and temperature part of bm p 280 table 2 : p arameter specification parameter symbol condition min typ max units operating temperature range t a operational - 40 25 +85 c full accuracy 0 +65 operating pressure range p full accuracy 300 1100 hpa sensor s upply voltage v dd ripple max. 50mvpp 1.71 1.8 3.6 v interface supply voltage v ddio 1.2 1.8 3.6 v supply current i dd,lp 1 hz forced mode, pressure and temperature, lowest power 2 . 8 4.2 a peak current i peak during pressure measurement 720 1120 a current at temperature measurement i ddt 325 a sleep current 1 i ddsl 25 c 0.1 0.3 a standby current (inactive period of normal mode) 2 i ddsb 25 c 0. 2 0. 5 a relative accuracy pressure 3 v dd = 3.3v a rel 700 900hpa 25 . . . 40 c 0.12 hpa 1.0 m 1 typical value at vdd = vddio = 1.8 v, maximal value at vdd = vddio = 3.6 v. 2 typical value at vdd = vddio = 1.8 v, maximal value at vdd = vddio = 3.6 v. 3 target values
datasheet BMP280 digital pressure sensor page 8 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. offset temperature coefficient 3 t co 900hpa 25 . . . 40 c 1.5 pa/ k 1 2. 6 cm/k absolute accuracy pressure a p ext 300 . . . 1100 hpa - 20 . . . 0 c 1. 7 hpa a p full 300 . . . 1100 hpa 0 . . . 65 c 1. 0 hpa resolution of output data in ultra high resolution mode 4 r p p ressure 0.0 0 1 6 hpa r t t emperature 0. 0 1 c noise in pressure v p,full full bandwidth, ultra high resolution see chapt er 3.5 1.3 pa 11 cm v p,filtered lowest bandwidth, ultra high resolution see chapter 3.5 0.2 pa 1. 7 cm absolute accuracy temperature 5 a t @ 25 c 0.5 c 0 . . . +65 c 1.0 c psrr (dc) psrr full v dd range 0.00 5 pa/ mv long term stability 6 ? p stab 12 months 1.0 hpa solder drifts ? minimum solder height 50 m - 0.5 +2 hpa start - up time t startup time to first communication after both v dd > 1.58v and v ddio > 0.65v 2 ms possible sampling rate f sample osrs_t = osrs_p = 1; see chapter 3.8 157 182 tbd 7 hz standby time accuracy ? t standby 5 2 5 % 4 using double precision or 64 bit integer compensation formula, 16oversampling 5 temperature measured by the internal temperature sensor. this temperature value depends on the pcb temperature, sensor element self - heating and ambient temperature and is typically above ambient temperature. 6 long term stability is specified in the full accuracy operating pressure range 0 65c 7 depends on application case, please contact application engineer for further questions
datasheet BMP280 digital pressure sensor page 9 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 2. absolute maximum ratings the absolute maximum ratings are provided in table 3 . table 3 : absolute maximum ratings parameter condition min max unit voltage at any s upply p in v dd and v dd io pin - 0.3 4. 25 v voltage at any interface pin - 0.3 v ddio + 0.3 v storage temp erature 65% rel. h. - 45 + 85 c pressure 0 2 0 000 hpa esd hbm, at any pin 2 kv cdm 500 v machine model 200 v
datasheet BMP280 digital pressure sensor page 10 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3. functional description the bm p280 consists of a piezo - resistive pressure sensing element and a mixed - signal asic. the asic performs a/d conversions and provides the conversion results and sensor specific compensation data through a digital interface. BMP280 provides highest flexibility to the designer and can be adapted to the requirements regarding accuracy, measurement time and power consumption by selecting from a high number of possible combinations of the sensor settings. BMP280 can be operated in three power modes (see chapter 3.6 ): ? sleep mode ? normal mode ? forced mode in sleep mode, no measurements are performed. normal mode comprises an automated perpetual cycling between an active measurement period and an inactive standby period. in forced mode, a single measurement is performed. when the measurement is finished, the sensor returns to sleep mode. a set of oversampling settings is available ranging from ultra low power to ultra high resolutio n setting in order to adapt the sensor to the target application. the settings are predefined combinations of pressure measurement oversampling and temperature measurement oversampling . pressure and temperature measurement oversampling can be selected inde pendently from 0 to 16 times oversampling (see chapter 3.3.1 and 3.3.2 ): ? temperature measurement ? ultra low power ? low power ? standard resolution ? high resolution ? ultra high resolution BMP280 is equipped with a built - in iir filter in order to minimize short - term disturbances in the output data caused by the slamming of a door or window. the filter coefficient ranges from 0 (off) to 16. in order to simplify the device usage and reduce the high number of possible combinations of power modes, oversampling rates and filter settings, bosch sensortec provides a p roven set of recommendations for common use - cases in smart - phones, mobile weather stations or flying toys (see chapter 3.4 ) : ? h andheld device low - power ( e.g. smart phones running android ) ? h andheld device dynamic (e.g. smart phones running android ) ? weather monitoring ( setting with lowest power consumption ) ? elevator / floor change detection ? drop detection ? indoor navigation
datasheet BMP280 digital pressure sensor page 11 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.1 block diagram figure 1 shows a simplified block diagram of the bm p280 : figure 1 : block diagram of bm p28 0 3.2 power management the BMP280 has two separate power supply pins ? v dd is the mai n power supply for all internal analog and digital functional blocks ? v ddio is a separate power su pply pin, used for the supply of the digital interface a power - on reset generator is built in which resets the logic circuitry and the register values after t he power - on sequence. there are no limitations on slope and sequence of raising the v dd and v ddio levels. after powering up, the sensor settles in sleep mode (see 3.6.1 ). warning. holding any interface pin (sdi, sdo, sck or csb) at a logical high level when v ddio is switched off can permanently damage the device due caused by excessive current flow th r ough the esd protection diodes. if v ddio is supplied, but v dd is not, the interface pins are kept at a high - z level. the bus can therefore already be used freely before the BMP280 v dd supply is established. 3.3 measurement flow the BMP280 measurement period consists of a temperature and pressure measurement with selectable oversampling. after the measurement period , the data are passed through an optional iir filter, which removes short - term fluctuations in pressure (e.g. caused by slamming a door). the flow is depicted in the diagram below. l o g i c o s c n v m a d c p r e s s u r e / t e m p e r a t u r e s e n s i n g e l e m e n t v o l t a g e r e f e r e n c e v o l t a g e r e g u l a t o r ( a n a l o g & d i g i t a l ) v d d i o g n d i n t e r f a c e s d i s d o s c k c s b v d d p o r a n a l o g f r o n t - e n d
datasheet BMP280 digital pressure sensor page 12 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. figure 2 : BMP280 measurement cycle the individual blocks of the diagram above will be detailed in the following subchapters. 3.3.1 pressure measurement pressure measurement can be enabled or skipped. skipping the measurement could be useful if BMP280 is used as temperature sensor. when enabled, s everal oversampling options exist. each oversampling step reduces noise and increases the output resolution by one bit, which is stored in the xlsb data register 0xf9 . enabling/disabling the measurement and oversampling setting s are selected through the os rs_p[2:0] bits in control register 0xf4 . table 4 : osrs_p settings oversampling setting pressure oversampling typical pressure resolution recommended temperature oversampling p ressure measurement skipped skipped (output set to 0x80000) C as needed ultra low power 1 16 bit / 2.62 pa 1 low power 2 17 bit / 1.31 pa 1 standard resolution 4 18 bit / 0.66 pa 1 high resolution 8 19 bit / 0.33 pa 1 ultra high resolution 16 20 bit / 0.16 pa 2 in order to find a suitable setting for osrs_p , please consult chapter 3.4 . m e a s u r e t e m p e r a t u r e ( o v e r s a m p l i n g s e t b y o s r s _ t ; s k i p i f o s r s _ t = 0 ) s t a r t m e a s u r e m e n t c y c l e m e a s u r e p r e s s u r e ( o v e r s a m p l i n g s e t b y o s r s _ p ; s k i p i f o s r s _ p = 0 ) i i r f i l t e r e n a b l e d ? e n d m e a s u r e m e n t c y c l e i i r f i l t e r i n i t i a l i s e d ? c o p y a d c v a l u e s t o f i l t e r m e m o r y ( i n i t a l i s e s i i r f i l t e r ) n o u p d a t e f i l t e r m e m o r y u s i n g f i l t e r m e m o r y , a d c v a l u e a n d f i l t e r c o e f f i c i e n t n o y e s y e s c o p y f i l t e r m e m o r y t o o u t p u t r e g i s t e r s
datasheet BMP280 digital pressure sensor page 13 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.3.2 temperature measurement temperature measurement can be enabled or skipped. skipping th e measurement could be useful to measure pressure extremely rapidly. when enabled, several oversampling options exist. each oversampling step reduces noise and increases t he output resolution by one bit, which is stored in the xlsb data register 0xfc . enab ling/disabling the temperature measurement and oversampling setting are selected through the osrs_t[2:0] bits in control register 0xf4 . table 5 : osrs_t settings osrs_t [2:0] temperature oversampling typical temperature resolution 000 skipped (output set to 0x80000) C 001 1 16 bit / 0.0050 c 010 2 17 bit / 0.0025 c 011 4 18 bit / 0.0012 c 100 8 19 bit / 0.0006 c 101, 110, 111 16 20 bit / 0.0003 c it is recommended to base the value of osrs_t on the selected value of osrs_p as per table 4. temperature oversampling above 2 is possible, but will not significantly improve the accuracy of the pressure output any further. the reason for this is that the noise of the compensated pressure value depends more on the raw pressure than on the raw temperature noise. following the recommended setting will result in an optimal noise - to - power ratio. 3.3.3 iir filter the environmental pressure is subject to many shor t - term changes, caused e.g. by slamming of a door or window, or wind blowing into the sensor. to suppress these disturbances in the output data without causing additional interface traffic and processor work load, the BMP280 features an internal iir filter . it effectively reduces the b andwidth of the output signals 8 . the output of a next measurement step is filter using the following formula: , w here data_filtered_old is the data coming from the previous acquisition, and data_adc i s the data coming from the adc before iir filtering. the iir filter can be configured using the filter[2:0] bits in control register 0xf5 with the following options : 8 since most pressure sensors do not sample continuously, filtering can suffer from signals with a frequency higher than th e sampling rate of the sensor. e.g. environmental fluctuations caused by windows being opened and closed might have a frequency <5 hz. consequently, a sampling rate of odr = 10 hz is sufficient to obey the nyquist theorem. t coefficien filter adc data t coefficien filter old filtered data filtered data _ _ ) 1 _ ( _ _ _ ? ? ? ?
datasheet BMP280 digital pressure sensor page 14 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. table 6 : filter settings filter [2:0] filter coefficient bandwidth (odr calculation see table 14 ) 000 filter off full 001 2 0.223 odr 010 4 0.092 odr 011 8 0.042 odr 100, others 16 0.021 odr in order to find a suitable setting for filter , please consult chapter 3.4 . when writing to the register filter , the filter is reset. the next value will pass through the filter and be the initial memory value for the filter. if temperature or pressure measurement is skipped, the corresponding filter memory will be kept unchanged even though the output registers ar e set to 0x80000. when the previously skipped measurement is re - enabled, the output will be filtered using the filter memory from the last time when the measurement was not skipped. 3.4 filter selection in order to select optimal settings, the following use c ases are suggested: table 7 : recommended filter settings based on use case s u se case mode over - sampling setting osrs_p osrs_t iir filter coeff. ( see 3.3.3 ) i dd [a] (see 3.7 ) odr [hz] (see 3.8.2 ) rms noise [cm] (see 3.5 ) handheld device low - power (e.g. android) normal ultra high resolution 16 2 4 247 10.0 4.0 handheld device dynamic (e.g. android) normal standard resolution 4 1 16 577 83.3 2.4 weather monitoring (lowest power) forced ultra low power 1 1 o ff 0.14 1/60 26.4 elevator / floor change detection normal standard resolution 4 1 4 50.9 7.3 6.4 drop detection normal low power 2 1 off 509 125 20.8 indoor navigation normal ultra high resolution 16 2 16 650 26.3 1.6
datasheet BMP280 digital pressure sensor page 15 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.5 noise n oise depends on the oversampling and filter setting s selected . the stated values were determined in a controlled pressure environment and are based on the average standard deviation of 32 consecutive measurement points taken at highest sampling speed. this is needed in order to exclude long term drifts from the nois e measurement. table 8 : noise in pressure typical rms noise in pressure [pa] oversampling setting iir filter coefficient off 2 4 8 16 ultra low power 3.3 1.9 1.2 0.9 0.4 low power 2.6 1.5 1.0 0.6 0.4 standard resolution 2.1 1.2 0.8 0.5 0.3 high resolution 1.6 1.0 0.6 0.4 0.2 ultra high resolution 1.3 0.8 0.5 0.4 0.2 table 9 : noise in temperature typical rms noise in temperature [c] temperature oversampling iir filter off oversampling 1 0.005 oversampling 2 0.004 oversampling 4 0.003 oversampling 8 0.003 oversampling 16 0.002 3.6 power modes the BMP280 offers three power modes: sleep mode, forced mode and normal mode. these can be selected using the mode[1:0] bits in control register 0xf4 . table 10 : mode settings mode [1:0] mode 00 sleep mode 01 and 10 forced mode 11 normal mode
datasheet BMP280 digital pressure sensor page 16 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.6.1 sleep mode sleep mode is set by default after power on reset. in sleep mode, no measurements are performed and power consumption (i ddsm ) is at a minimum. all registers are accessible; chip - id and compensation coefficients can be read. 3.6.2 forced mode in forced mode, a single measurement is performed according to selected measurement and filter options. when the measurement is finished, the s ensor returns to sleep mode and the measurement results can be obtained from the data registers. for a next measurement, forced mode needs to be selected again. this is similar to bmp180 operation. forced mode is recommended for applications which require low sampling rate or host - based synchronization. figure 3 : force d mode timing diagram 3.6.3 normal mode normal mode continuosly cycl es between an (active) measurement period and an (inactive) standby period , whose time is defined by t standby . the current in the standby period (i dds b ) is slightly higher than in sleep mode. after setting the mode , measurement and filter options, the last measurement results can be obtained from the data registers without the ne ed of further write accesses. n ormal mode is recommended when using the iir filter , and useful for applications in which short - term disturbances (e.g. blowing into the sensor) should be filtered. figure 4 : normal mode timing diagram t i m e c u r r e n t i d d s l i d d s b i d d p i d d t p o r m o d e [ 1 : 0 ] = 0 1 m e a s u r e m e n t t m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t t m e a s u r e m e n t t m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t t d a t a r e a d o u t o s r s _ t o s r s _ p w r i t e s e t t i n g s m o d e [ 1 : 0 ] = 0 1 t i m e c u r r e n t i d d s l i d d s b i d d p i d d t p o r m o d e [ 1 : 0 ] = 1 1 m e a s u r e m e n t t m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t t m e a s u r e m e n t t m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t p m e a s u r e m e n t t d a t a r e a d o u t w h e n n e e d e d o s r s _ t o s r s _ p w r i t e s e t t i n g s t s t a n d b y
datasheet BMP280 digital pressure sensor page 17 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. the standby time is determined by the contents of the t_sb[2:0] bits in control register 0xf5 according to the table below: table 11 : t _ sb settings t_ sb [1:0] t standby [ms] 000 0.5 001 62.5 010 125 011 250 100 500 101 1000 110 2000 111 4000 3.6.4 mode transition diagram the supported mode transitions are displayed below. if the device is currently performing a measurement, e xecution of mode switching command s is del a yed until the en d of the currently running measurement period. further mode change commands are ignored until the last mode change command is executed. mode transitions other than the ones shown below are tested for stability but do not represent recommended use of the de vice. figure 5 : mode transition diagram p o w e r o f f ( v d d o r v d d i o = 0 ) v d d a n d v d d i o s u p p l i e d m o d e [ 1 : 0 ] = 0 0 m o d e [ 1 : 0 ] = 0 1 s l e e p n o r m a l ( c y c l i c s t a n d b y a n d m e a s u r e m e n t p e r i o d s ) m o d e [ 1 : 0 ] = 1 1 f o r c e d ( o n e m e a s u r e m e n t p e r i o d ) m o d e [ 1 : 0 ] = 0 1
datasheet BMP280 digital pressure sensor page 18 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.7 current consumption the current consumption depends on odr and oversampling setting. the values given below are normalized to an odr of 1 hz. the actual consumption at a given odr can be calculated by multiplying the consumption in table 12 with the odr used. the actual odr is defined either by the frequency at which the user sets forced measurements or by oversampling and t standby settings in normal mode in table 14 . table 12 : c urrent consumption oversampling setting pressure oversampling temperature oversampling i dd [a] @ 1 hz forced mode typ max ultra low power 1 1 2.74 4.16 low power 2 1 4.17 6.27 standard resolution 4 1 7.02 10.50 high resolution 8 1 12.7 18.95 ultra high resolution 16 2 24.8 36.85 3.8 measurement timings the rate at which measurements can be performed in forced mode depends on the oversampling settings osrs_t and osrs_p . the rate at which they are performed in normal mode depends on the oversampling setting settings osrs_t and osrs_ p and the standby time t standby . in the following table the resulting odrs are given only for the suggested osrs combinations. 3.8.1 measurement time the following table explains the typical and maximum measurement time based on selected oversampling setting . the minimum achievable frequency is d etermined by the maximum measurement time. table 13 : measurement time oversampling setting pressure oversampling temperature oversampling measurement time [ms] measurement rate [hz] typ max typ min ultra low power 1 1 5.5 6.4 181.8 155.6 low power 2 1 7.5 8.7 133.3 114.6 standard resolution 4 1 11.5 13.3 87.0 75.0 high resolution 8 1 19.5 22.5 51.3 44.4 ultra high resolution 16 2 37.5 43.2 26.7 23.1
datasheet BMP280 digital pressure sensor page 19 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.8.2 measurement rate in normal mode the following table explains which measurement rates can be expected in normal mode based on oversampling setting and t standby . table 14 : t ypical output data rate (odr) in normal mode [hz] oversampling setting t standby [ms] 0.5 62.5 125 250 500 1000 2000 4000 ultra low power 166.67 14.71 7.66 3.91 1.98 0.99 0.50 0.25 low power 125.00 14.29 7.55 3.88 1.97 0.99 0.50 0.25 standard resolution 83.33 13.51 7.33 3.82 1.96 0.99 0.50 0.25 high resolution 50.00 12.20 6.92 3.71 1.92 0.98 0.50 0.25 ultra high resolution 26.32 10.00 6.15 3.48 1.86 0.96 0.49 0.25 table 15 : sensor timing according to recommended settings (based on use cases) u se case mode over - sampling setting osrs_p osrs_t iir filter coeff. (see 3.3.3 ) timing od r [hz] (see 3.8.2 ) bw [hz] (see 3.3.3 ) handheld device low - power (e.g. android) normal ultra high resolution 16 2 4 t standby = 62.5 ms 10.0 0.92 handheld device dynamic (e.g. android) normal standard resolution 4 1 16 t standby = 0.5 ms 83.3 1.75 weather monitoring (lowest power) forced ultra low power 1 1 off 1/min 1/60 full elevator / floor change detection normal standard resolution 4 1 4 t standby = 125 ms 7.3 0.67 drop detection normal low power 2 1 off t standby = 0.5 ms 125 full indoor navigation normal ultra high resolution 16 2 16 t standby = 0.5 ms 26.3 0.55 3.9 data readout to read out data after a conversion, it is strongly recommended to use a burst read and not address every register individually. this will prevent a possible mix - up of bytes belonging to different measurements and reduce interface traffic. data readout is done by starting a burst read from 0xf7 to 0xfc. the data are read out in an unsigned 20 - bit format both for pressure and for temperature. it is strongly recommended to use the BMP280 api, available from bosch sensortec, for readout and compensation. for d etails on memory map and interfaces, please consult chapters 3.12 and 5 respectively.
datasheet BMP280 digital pressure sensor page 20 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. the timing for data readout in forced mode should be done so that the maximum measurement times (see chapter 3.8.1 ) are respected. in normal mode, readout can be done at a speed similar to the expected data output rate (see cha pter 3.8.2 ). after the values of ut and up have been read, the actual pressure and temperature need to be calculated using the compensation parameters stored in the device. the procedure is elaborated in chapter 3.11 . 3.10 data register shadowing in normal mode, measurement timing is not necessarily synchronized to readout. this means that new measurement results may become available while the user is reading the results from the previous measurement. in this case, shadowing is performed in order to guarantee data consist en cy. shad owing will only work if all data registers are read in a single burst read. therefore, the user must use burst reads if he does not synchronize data readout with the measurement cycle. using several independent read commands may result in inconsistent data . if a new measurement is finished and the data registers are still being read, the new measurement results are transferred into shadow data registers. the content of shadow registers is transferred into data registers as soon as the user ends the burst read, even if not all data registers were read. reading across several data registers can therefore only be guaranteed to be consistent with in one measurement cycle if a single burst read command is used. the end of the burst read is marked by the rising e dge of csb pin in spi case or by the recognition of a stop condition in i2c case. after the end of the burst read, all user data registers are updated at once. 3.11 output compensation the BMP280 output consists of the adc output values. however, each sensing element behaves differently , and actual pressure and temperature must be calculated using a set of calibration parameters . the recommended calculation in chapter 3.11.3 uses fixed point arithmetic. in high - level languages like matlab? or labview? , fixed - point code may not be well supported. in this case the floating - point code in appendix 8.1 can be used as an alternative. for 8 - bit micro controllers, the variable size may be limited. in this case a simplified 32 bit integer code with reduced accuracy is given in appendix 8.2 . 3.11.1 computational requirements t he table below shows the number of clock cycles needed for compensation calculations on a 32 bit cortex - m3 micro controller with gcc optimization level - o2 . this controller does not contain a floating point unit, so all floating - point calculations are emulated. floating point is only recommended for pc application s where an fpu is present . table 16 : computational requirements for compensat ion formulas compensation of number of clock cycles ( arm cortex - m3 ) 32 bit integer 64 bit integer double precision temperature ~ 46 C ~ 2400 9 pressure ~ 112 10 ~ 1400 ~ 5400 9 9 use only recommended for high - l evel programming languages like matlab? or labview? 10 use only recommended for 8 - bit micro controllers
datasheet BMP280 digital pressure sensor page 21 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 3.11.2 trimming parameter readout the trimming parameters are programmed into the devices non - volatile memory (nvm) during production and cannot be altered by the customer. each compensation word is a 16 - bit signed or unsigned integer value stored in twos complement. as the memory is org anized into 8 - bit words, two words must always be combined in order to represent the compensation word. the 8 - bit registers are named calib00calib25 and are stored at memory addresses 0x880xa1. the corresponding compensation words are named dig_t # for te mperature compen sation related values and dig_p# for pressure compensation related values. the mapping is shown in table 17 . table 17 : compensation parameter storage, naming and data type register address lsb / msb register content data type 0x88 / 0x89 dig_t1 unsigned short 0x8a / 0x8b dig_t2 signed short 0x8c / 0x8d dig_t3 signed short 0x8e / 0x8f dig_p1 unsigned short 0x90 / 0x91 dig_p2 signed short 0x92 / 0x93 dig_p3 signed short 0x94 / 0x95 dig_p4 signed short 0x96 / 0x97 dig_p5 signed short 0x98 / 0x99 dig_p6 signed short 0x9a / 0x9b dig_p7 signed short 0x9c / 0x9d dig_p8 signed short 0x9e / 0x9f dig_p9 signed short 0xa0 / 0xa1 reserved reserved 3.11.3 compensation formula please note that it is strongly advised to use the api available from bosch sensortec to perform readout and compensation . if this is not wanted, the code below can be applied at the users risk. both pressure and temperature values are expected to be received in 20 bit format, positive, stored in a 32 bit signed integer. the variable t_ fine (signed 32 bit) carries a fine resolution temperature value over to the pressure compensation formula and could be implemented as a global variable. the data type BMP280_s32_t should define a 32 bit signed integer variable type and can usually be d efined as long signed int. the data type BMP280_u32_t should define a 32 bit unsigned integer variable type and can usually be defined as long unsigned int.
datasheet BMP280 digital pressure sensor page 22 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. for best possible calculation accuracy, 64 bit integer support is needed. if this is not possible on your platform, please see appendix 8.2 for a 32 bit alternative. t he data type BMP280_s64_t should define a 64 bit signed integer variable type, whi ch on most supporting platforms can be defined as long long signed int. the revision of the code is rev.1.1. // returns temperature in degc, resolution is 0.01 degc. output value of 5123 equals 51.23 degc. // t_fine carries fine temperature as global value BMP280_s32_t t_fine; BMP280_s32_t BMP280_compensate_t_int32( BMP280_s32_t adc_t) { BMP280_s32_t var1, var2, t; var1 = ((((adc_t>>3) C (( BMP280_s32_t )dig_t1<<1))) * (( BMP280_s32_t )dig_t2)) >> 11; var2 = (((((adc_t>>4) C (( BMP280_s32_t )dig_t1)) * ((adc_t>>4) C (( BMP280_s32_t )dig_t1))) >> 12) * (( BMP280_s32_t )dig_t3)) >> 14; t_fine = var1 + var2; t = (t_fine * 5 + 128) >> 8; return t; } C // returns pressure in pa as unsigned 32 bit integer in q24.8 format (24 integer bits and 8 fractional bits). // output value of 24674867 represents 24674867/256 = 96386.2 pa = 963.862 hpa BMP280_u32_t BMP280_compensate_p_int64( BMP280_s32_t adc_p) { BMP280_s64_t var1, var2, p; var1 = (( BMP280_s64_t )t_fine) C 128000; var2 = var1 * var1 * ( BMP280_s64_t )dig_p6; var2 = var2 + ((var1*( BMP280_s64_t )dig_p5)<<17); var2 = var2 + ((( BMP280_s64_t )dig_p4)<<35); var1 = ((var1 * var1 * ( BMP280_s64_t )dig_p3)>>8) + ((var1 * ( BMP280_s64_t )dig_p2)<<12); var1 = ((((( BMP280_s64_t )1)<<47)+var1))*(( BMP280_s64_t )dig_p1)>>33; if (var1 == 0) { return 0; // avoid exception caused by division by zero } p = 1048576 - adc_p; p = (((p<<31) - var2)*3125)/var1; var1 = ((( BMP280_s64_t )dig_p9) * (p>>13) * (p>>13)) >> 25; var2 = ((( BMP280_s64_t )dig_p8) * p) >> 19; p = ((p + var1 + var2) >> 8) + ((( BMP280_s64_t )dig_p7)<<4); return ( BMP280_u32_t )p; 3.12 calculating pressure and temperature the following figure shows the detailed algorithm for pressure and temperature measurement. this algorithm is available to c ustomers as reference c source code ( bmp28 x _ api) from bosch sensortec and via its sales and distribution partners. please contact your bosch sensortec representative for details.
datasheet BMP280 digital pressure sensor page 23 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication.
datasheet BMP280 digital pressure sensor page 24 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 4. global memory map and register description 4.1 general remarks all c ommuni cation with the device is performed by reading from and writing to registers. r egisters have a width of 8 bits . t here are several registers which are reserved ; they should not be written to and no specific value is guaranteed when they are read. for details on the interface, consult chapter 5 . 4.2 memory map the memory map is given in table 18 below. reserved registers are not shown. table 18 : memory map 4.3 register description 4.3.1 register 0x d 0 id the id register contains the chip identification number chip_id[7:0] , which is 0x 5 8 . this number can be read as soon as the device finished the power - on - reset . 4.3.2 register 0x e 0 reset the reset register contains the soft reset word reset[7:0]. if the value 0xb6 is written to the register, the device is reset using the complete power - on - reset procedure. writing other values than 0xb6 has no effect. the readout value is always 0x00. register name address bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 reset state temp_xlsb 0xfc 0 0 0 0 0x00 temp_lsb 0xfb 0x00 temp_msb 0xfa 0x80 press_xlsb 0xf9 0 0 0 0 0x00 press_lsb 0xf8 0x00 press_msb 0xf7 0x80 config 0xf5 spi3w_en[0] 0x00 ctrl_meas 0xf4 0x00 status 0xf3 measuring[0] im_update[0] 0x00 reset 0xe0 0x00 id 0xd0 0x58 calib25...calib00 0xa10x88 individual registers:? reserved registers calibration data control registers data registers status registers revision reset type:? do not write read only read / write read only read only read only write only press_lsb<7:0> press_msb<7:0> mode[1:0] t_sb[2:0] filter[2:0] osrs_p[2:0] calibration data press_xlsb<7:4> temp_xlsb<7:4> temp_lsb<7:0> temp_msb<7:0> chip_id[7:0] osrs_t[2:0] reset[7:0]
datasheet BMP280 digital pressure sensor page 25 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 4.3.3 register 0x f3 status the status register contains two bits which indicate the status of the device . table 19 : register 0xf3 status register 0x f 3 status name description bit 3 m easuring[0] automatically s et to 1 whenever a conversion is running and back to 0 when the results have been transferred to the data registers. bit 0 i m_update[0] automatically s et to 1 when the nvm data are being copied to image registers and back to 0 when the copying is done. the data are copied at power - on - reset and before every conversion. 4.3.4 register 0x f4 ctrl_meas the ctrl_meas register sets the data acquisition options of the device. table 20 : register 0xf4 ctrl_meas register 0x f4 ctrl_meas name description bit 7, 6, 5 osrs_t[2:0] controls oversampling of temperature data. see chapter 3.3.2 for details. bit 4, 3, 2 osrs_p[2: 0] controls oversampling of pressure data. see chapter 3.3.1 for details. bit 1, 0 mode[1:0] controls the power mode of the device. see chapter 3.6 for details. table 21 : register settings osrs_p osrs_p [2:0] pressure oversampling 000 skipped (output set to 0x80000) 001 oversampling 1 010 oversampling 2 011 oversampling 4 100 oversampling 8 101, others oversampling 16
datasheet BMP280 digital pressure sensor page 26 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. table 22 : register settings osrs_t osrs_t [2:0] temperature oversampling 000 skipped (output set to 0x80000) 001 oversampling 1 010 oversampling 2 011 oversampling 4 100 oversampling 8 101, 110, 111 oversampling 16 4.3.5 register 0x f5 config the config register sets the rate, filter and interface options of the device. writes to the config register in normal mode may be ignored . in sleep mode writes are not ignored. table 23 : register 0xf 5 config register 0xf5 config name description bit 7, 6, 5 t_sb[2:0] controls inactive duration t standby in normal mode. see chapter 3.6.3 for details. bit 4, 3, 2 filter[2:0] controls the time constant of the iir filter. see chapter 3.3.3 for details. bit 0 spi3w_en[0] enables 3 - wire spi interface when set to 1. see chapter 5.3 for details. 4.3.6 register 0x f70xf9 press (_msb, _lsb, _xlsb) the press register contains the raw pressure measurement output data up[19:0]. for details on how to read out the pressure and temperature information from the device, please consult chapter 3.9 . table 24 : register 0xf 7 0xf9 press register 0xf7 - 0xf9 press name description 0xf7 press_msb[7:0] contains the msb part up[19:12] of the raw pressure measurement output data. 0xf8 press_lsb[7:0] contains the lsb part up[11:4] of the raw pressure measurement output data. 0xf9 (bit 7, 6, 5, 4 ) press_x l sb[3:0] contains the xlsb part up[3:0] of the raw pressure measurement output data. contents depend on temperature resolution, see table 5 .
datasheet BMP280 digital pressure sensor page 27 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 4.3.7 register 0xfa0xfc temp (_msb, _lsb, _xlsb) the temp register contains the raw temperature measurement output data ut[19:0]. for details on how to read out the pressure and temperature information from the device, please consult chapter 3.9 . table 25 : register 0xf a 0xfc temp register 0xf7 - 0xf9 press name description 0xfa temp_msb[7:0] contains the msb part ut[19:12] of the raw temperature measurement output data. 0xfb temp_lsb[7:0] contains the lsb part ut[11:4] of the raw temperature measurement output data. 0xfc (bit 7, 6, 5, 4 ) temp_x l sb[3:0] contains the xlsb part ut[3:0] of the raw temperature measurement output data. contents depend on pressure resolution, see table 4 .
datasheet BMP280 digital pressure sensor page 28 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 5. digital interfaces the BMP280 supports the i2c and spi digital interfaces ; it acts as a slave for both protocols . the i2c interface supports the standard, fast and high speed modes. the spi int erface supports both spi mode 0 0 ( cpol = cpha = 0 ) and mode 11 ( c pol = cpha = 1 ) in 4 - wire and 3 - wire configuration. the following transactions are supported: ? single byte write ? multiple byte write (using pairs of register addresses and register data) ? single byte read ? multiple byte read (using a single register addr ess which is auto - incremented) 5.1 interface selection interface selection is done automatically based on csb (chip select) status. if csb is connected to v ddio , the i2c interface is active. if csb is pulled down, the spi interface is activated. after csb has been pulled down once (regardless of whether any clock cycle occurred), the i2c interface is disabled until the next power - on - reset. this is done in order t o avoid inadvertently decoding spi traffic to another slave as i2c data. since power - on - reset is only executed when both v dd and v ddio are established, there is no risk of incorrect protocol detection due to power - up sequence used. however, if i2c is to be used and csb is not directly connected to v ddio but rather through a programmable pin, it must be ensured that this pin already outputs the v ddio level during power - on - reset of the device. if this is not the case, the device will be locked in spi mode and not respond to i2c commands. 5.2 i2c interface the i 2 c slave interface is compatible with philips i 2 c specification version 2.1. f or detailed timings refer to table 27 . all modes (standard, fast, high speed) are supported. sda and scl are not pure open - drain. both pads contain esd protection diodes to vddio and gnd. as the devices does not perform clock str etching, the scl structure is a high - z input without drain capability . figure 6 : sdi/sck esd drawing the 7 - bit device address is 111011 x . the 6 msb bits are fixed . the last bit is changeable by sdo va lue and can be changed during operation . connecting sdo to gnd results in slave address 1110110 (0x76) ; connection it to v ddio re sults in slave address 1110111 (0x77) , which g n d v d d i o o u t p u t d r i v e r ( o n l y f o r s d i ) s d i / s c l h i g h - z l e v e l s h i f t e r g n d
datasheet BMP280 digital pressure sensor page 29 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. is the same as bmp180 s i2c address . the sdo pin cannot be left floating; if left floating, the i2c address will be undefined. the i2c interface uses the following pins: ? sck: s erial c lock (scl ) ? sdi : data ( sda ) ? sdo: slave address lsb (gnd = 0, v ddio = 1) csb must be connected to v ddio to select i2c interface . sdi is bi - dir ectional with open drain to gnd : it must be externally connected to v ddio via a pull up resistor. refer to chapter 6 for connection instructions. the following ab breviations will be used in the i2c protocol figures : ? s start ? p stop ? acks acknowledge by slave ? ackm acknowledge by master ? nackm not acknowledge by master 5.2.1 i2c write writing is done by sending the slave address in write mode (rw = 0) , resulting in slave address 111011 x 0 ( x is determined by state of sdo pin . then the master sends pairs of register address es and register data. the transaction is ended by a stop condition. this is depicted in figure 7 . figure 7 : i2c multiple byte write (not auto - incremented) 5.2.2 i2c read to be able to read regi s ters , first the register address must be sen t i n write mode (slave address 111011x0). then either a stop or a repeated start condition must be generated. after this the slave is addressed in read mode (rw = 1) at address 111011x1, after which the slave sends out data from auto - incremented register ad dresses until a noackm and stop condition occurs. this is depicted in figure 8 , where two bytes are read from register 0xf6 and 0xf7. start rw acks acks acks 1 1 1 0 1 1 x 0 1 0 1 0 0 0 0 0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 acks acks stop 1 0 1 0 0 0 0 1 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 register data - address a0h register address (a0h) register address (a1h) s slave address control byte data byte control byte data byte p register data - address a1h
datasheet BMP280 digital pressure sensor page 30 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. figure 8 : i2c multiple byte read 5.3 spi interface the spi interface is compatible with spi mode 00 (cpol = cpha = 0) and mode 11 (cpol = cpha = 1) . the automatic selection between mode 00 and 11 is determined by the value of sck after the csb falling edge. the spi interface has two modes : 4 - wire and 3 - wire. the protocol is the same for both. the 3 - wire mode is selected by setting 1 to the register spi 3w_en. the pad sdi is used as a data pad in 3 - wire mode. start rw acks acks 1 1 1 0 1 1 x 0 1 1 1 1 0 1 1 0 start rw acks ackm noackm stop 1 1 1 0 1 1 x 1 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 control byte data byte data byte register address (f6h) s slave address p s slave address register data - address f7h register data - address f6h
datasheet BMP280 digital pressure sensor page 31 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. the spi i nterface uses the following pins: ? csb : chip select, active low ? sck : serial clock ? sdi : serial data input; data input/output in 3 - wire mode ? sdo : serial data output; h i - z in 3 - wire mode refer to chapter 6 for connection instructions. csb is active low and has an integrated pull - up resistor. data on sdi is latched by the device at sck rising edge and sdo is changed at sck falling edge. communication starts when csb goes to low and stops when csb goes to high; during these transitions on csb, sck must be stable. the spi protocol is shown in figure 9 . for timing details, please rev iew table 28 . figure 9 : spi protocol (shown for mode 11 in 4 - wire configuration) in spi mode, only 7 bits of the register addresses are used; the msb of register address is not used and replaced by a read/write bit (rw = 0 for write and rw = 1 for read). example: address 0x f7 is accessed by using spi register address 0x 77. for write acce ss, the byte 0x77 is transferred, for read access, the byte 0xf7 is transferred. 5.3.1 spi write writing is done by lowering csb and sending pairs control bytes and register data. the control bytes consist of the spi register address (= full register address wi thout bit 7) and the write command ( bit7 = rw = 0) . several pairs can be written without raising csb. the transaction is ended by a raising csb . the spi write protocol is depicted in figure 10 . figure 10 : spi multiple byte write (not auto - incremented) 5.3.2 spi read reading is done by lowering csb and first sending one control byte. the control bytes consist of the spi register address (= full register address without bit 7) and the read command (bit 7 = rw = 1). after writing the control byte, data is sent out of the sdo pin (sdi in 3 - wire mode); the register address is automatically i ncremented. the spi read protocol is shown in figure 11 . csb sck sdi rw ad 6 ad 5 ad 4 ad 3 ad 2 ad1 ad0 di5 di4 di3 di2 di1 di0 di7 di6 sdo do5 do4 do3 do2 do1 do0 do7 do6 tri - state start rw rw stop 0 1 1 1 0 1 0 0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 0 1 1 1 0 1 0 1 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 control byte csb = 1 data byte register address (f5h) data register - adress f5h register address (f4h) csb = 0 control byte data byte data register - address f4h
datasheet BMP280 digital pressure sensor page 32 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. figure 11 : spi multiple byte read 5.4 interface parameter specification 5.4.1 general interface parameters the general interface parameters are given in table 26 below . table 26 : interface p arameters parameter symbol condition min typ max units input C low level vil_si v ddio =1.2v to 3.6v 0.2 * v ddio v input C high level vih_si v ddio =1.2v to 3.6v 0.8 * v ddio v output C low level for i2c vol_sdi v ddio =1.62v, iol=3 ma 0.2 * v ddio v output C low level for i2c vol_sdi _1.2 v ddio =1.20v, iol=3 ma 0.2 3 * v ddio v output C low level vol_sd o v ddio =1.62v, iol=1 ma 0.2 * v ddio v output C low level vol_sd o_1.2 v ddio =1.20v, iol=1 ma 0.23 * v ddio v output C high level voh v ddio =1.62v, ioh=1 ma (sdo, sdi) 0.8 * v ddio v output C high level voh_1.2 v ddio =1.2v, ioh=1 ma (sdo, sdi) 0.6 * v ddio v pull - up resistor rpull internal pull - up resistance to v ddio 70 120 190 k i 2 c bus load capacitor cb on sdi and sck 400 pf 5.4.2 i2c timing s for i2c timings, the following abbreviations are used: ? s&f mode = standard and fast mode ? hs mode = high speed mode ? cb = bus capacitance on sda line all other n aming refers to i 2 c spec ification 2.1 (january 2000). the i2c timing diagram is shown in figure 12 . the corresponding values are given in table 27 . start rw stop 1 1 1 1 0 1 1 0 bit15 bit14 bit13 bit12 bit11 bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 csb = 1 data byte data register - address f7h register address (f6h) csb = 0 control byte data byte data register - address f6h
datasheet BMP280 digital pressure sensor page 33 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. figure 12 : i2c timing diagram table 27 : i2c timings parameter symbol condition min typ max units sdi setup time t su;dat s&f mode hs mode 160 30 ns ns sdi hold time t hd;dat s&f mode, cb100 pf s&f mode, cb400 pf hs mode, cb100 pf hs mode, cb400 pf 80 90 18 24 115 150 ns ns ns ns sck low pulse t low hs mode, cb100 pf v ddio = 1.62 v 160 ns sck low pulse t low hs mode, cb100 pf v ddio = 1.2 v 210 ns the above - mentioned i2c specific timings correspond to the following internal added delays: ? input d elay between sdi and sck inputs: sdi is more delayed than sck by typically 100 ns in standard and fast modes and by typically 20 ns in high speed mode. ? output delay from sck falling edge to sdi output propagation is typically 140 ns in standard and fast modes and typically 70 ns in high speed mode. 5.4.3 spi timings the spi timing diagram is in figure 13 , while the corresponding values are given in table 28 . all timings apply both to 4 - and 3 - wire spi. t hddat t f t buf sd i sck sd i t low t hdsta t r t susta t high t sudat t susto
datasheet BMP280 digital pressure sensor page 34 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. figure 13 : spi timing diagram table 28 : spi timings parameter symbol condition min typ max units spi clock input frequency f_spi 0 10 mhz sck low pulse t _low_sck 20 ns sck high pulse t _ high_sck 20 ns sdi setup time t _ setup_sdi 20 ns sdi hold time t _ hold_sdi 20 ns sdo output delay t _ delay_sdo 25pf load, v ddio =1.6v min 30 ns sdo output delay t _ delay_sdo 25pf load, v ddio =1.2v min 40 ns csb setup time t _ setup_csb 20 ns csb hold time t _ hold_csb 20 ns csb sck t_setup_csb t_ low _ sck t_ high _ sck t_hold _csb sdi t_setup_ sdi t_hold _ sdi sdo t_delay _ sdo
datasheet BMP280 digital pressure sensor page 35 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 6. pin - out and connection diagram 6.1 pin - out figure 14 : pin - out top and bottom view table 29 : pin description pin name i/o type description connect to spi 4w spi 3w i2c 1 gnd supply ground gnd 2 csb in chip select csb csb v ddio 3 sdi in/out serial data input sdi sdi/sdo sda 4 sck in serial clock input sck sck scl 5 sdo in/out serial data output sdo dnc gnd for default address 6 v ddio supply digital interface supply v ddio 7 gnd supply ground gnd 8 v dd supply analog supply v dd t o p v i e w ( p a d s n o t v i s i b l e ) 8 v d d 7 g n d 6 v d d i o 5 s d o 1 g n d 2 c s b 3 s d i 4 s c k b o t t o m v i e w ( p a d s v i s i b l e ) 8 v d d 7 g n d 6 v d d i o 5 s d o 1 g n d 2 c s b 3 s d i 4 s c k v e n t h o l e p i n 1 m a r k e r
datasheet BMP280 digital pressure sensor page 36 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 6.2 connection diagram 4 - wire spi figure 15 : 4 - wire spi connection diagram (pin1 marking indicated) note: the recommended value for c 1 , c 2 is 100 nf. t o p v i e w ( p a d s n o t v i s i b l e ) 8 v d d 7 g n d 6 v d d i o 5 s d o 1 g n d 2 c s b 3 s d i 4 s c k s d i c 1 s c k v d d i o v d d c 2 s d o c s b v e n t h o l e
datasheet BMP280 digital pressure sensor page 37 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 6.3 connection diagram 3 - wire spi figure 16 : 3 - wire spi connection diagram (pin1 marking indicated) note: the recommended value for c 1 , c 2 is 100 nf . t o p v i e w ( p a d s n o t v i s i b l e ) 8 v d d 7 g n d 6 v d d i o 5 s d o 1 g n d 2 c s b 3 s d i 4 s c k s d i / s d o c 1 s c k v d d i o v d d c 2 c s b v e n t h o l e
datasheet BMP280 digital pressure sensor page 38 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 6.4 connection diagram i 2 c figure 17 : i2c connection diagram (pin1 marking indicated) note s : ? t he recommended value for c 1 , c 2 is 100 nf. ? a direct connection between csb and v ddio is recommended. if csb is detected as low during start up , the interface will be lock ed into spi mode. see chapter 5.1 . t o p v i e w ( p a d s n o t v i s i b l e ) 8 v d d 7 g n d 6 v d d i o 5 s d o 1 g n d 2 c s b 3 s d i 4 s c k s d a c 1 s c l v d d i o v d d c 2 i 2 c a d d r e s s b i t 0 g n d : ' 0 ' ; v d d i o : ' 1 ' v e n t h o l e
datasheet BMP280 digital pressure sensor page 39 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7. package , reel and environment 7.1 outline dimensions the sensor housing is a n 8 - pin metal - lid lga 2.0 2.5 0.95 mm 3 package. its dimensions are depicted in figure 18 . figure 18 : package outline dimen sions for top , bottom and side view note: general tolerances are 50 m (linear) and 1 m (angular)
datasheet BMP280 digital pressure sensor page 40 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7.2 landing pattern recommendation for the design of the landing pattern, the following dimensioning is recommended : figure 19 : recommended l anding pattern (top view) ; dimensions are in mm note: red areas demark exposed pcb metal pads. ? in case of a solder mask defined (smd) pcb process, the land dimensions should be defined by solder mask openings. the underlying metal pa ds are larger than these openings. ? in case of a non solder mask defined (nsmd) pcb process, the land dimensions should be defined in the metal layer. the mask openings are larger than the these metal pads. 0 . 3 5 2 . 5 0 0 . 6 5 0 . 5 0 . 5 5 2 . 0 8 7 6 5 1 2 3 4 0 . 3 2 5
datasheet BMP280 digital pressure sensor page 41 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7.3 marking 7.3.1 mass production devices table 30 : marking of mass production samples labeling name symbol remark lot counter ccc 3 alphanumeric digits, variable to generate mass production trace - code product number t 1 alphanumeric digit, fixed to identify product type, t = k k is associated with the product BMP280 (part number 0 273 300 354) sub - con id l 1 alphanumeric digit, variable to identify sub - con (l = a or l = u or l = p) orientation marker ? vent hole 7.3.2 engineering samples table 31 : marking of engineering samples labeling name symbol remark eng. s ample id n 1 alphanumeric digit, fixed to identify engineering sample, n = * or e or e sample id xx 2 alphanumeric digits, variable to generate trace - code counter id cc 2 alphanumeric digits, variable to generate trace - code orientation marker ? vent hole xxn cc ? ccc tl ?
datasheet BMP280 digital pressure sensor page 42 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7.4 soldering guidelines the moisture sensitivity level of the bm p280 sensors corresponds to jedec level 1, see also: ? ipc/jedec j - std - 020c joint industry standard: moisture/reflow sensitivity classification for non - hermetic solid state surface mount devices ? ipc/jedec j - std - 033a joint industry standard: handling, packing, shipping and use of moisture/reflow sensitive surface mount devices . the sensor fulfils the lead - free soldering requirements of the above - mentioned ipc/jedec standard, i.e. reflow soldering with a peak temperature up to 260c. the minimum height of the solder after reflow shall be at least 50m. this is required for good mechanical decoupling between the sensor devi ce and the printed circuit board (pcb). figure 20 : soldering profile
datasheet BMP280 digital pressure sensor page 43 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7.5 t ape and reel specific ation 7.5.1 d imensions figure 21 : tape and reel dimensions quantity per reel: 10 kpcs. 7.5.2 orientation within the reel reel direction figure 22 : orientation within tape 1 2 3 4 8 7 6 5 pin
datasheet BMP280 digital pressure sensor page 44 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 7.6 mounting and assembly recommendations in addition to handling, soldering & mounting instructions bmp 2 80 , the following recommendations should be taken into consideration when mounting a pressure sensor on a printed - circuit board (pcb): ? the clearance above the metal lid shall be 0.1mm at minimum. ? for the device housing appropriate venting needs to be provided in case the ambient pressure shall be measured. ? liquids shall not come into direct contact with the device. ? during operation the sensor chip is sensitive to light, which can influence the ac curacy of the measurement (photo - current of silicon). the position of the vent hole minimizes the light exposure of the sensor chip. nevertheless, bst recommends to avoid the exposure of BMP280 to strong light sources. ? soldering may not be done using vapo r phase processes since the sensor might be damaged. 7.7 environmental safety 7.7.1 rohs the bm p280 sensor meets the requirements of the ec restriction of hazardous substances (rohs) directive, see also: directive 2002/95/ec of the european parliament and of the co uncil of 8 september 20 11 on the restriction of the use of certain hazardous substances in electrical and electronic equipment. 7.7.2 halogen content the bm p280 is halogen - free. for more details on the analysis results please contact your bosch sensortec represe ntative. 7.7.3 internal package structure within the scope of bosch sensortecs ambition to improve its products and secure the mass product supply, bosch sensortec qualifies additional sources (e.g. 2 nd source) for the lga package of the bm p280 . while bosch sensortec took care that all of the technical packages parameters are described above are 100% identical for all sources, there can be differences in the chemical content and the internal structural between the different package sources. however, as secur ed by the extensive product qualification process of bosch sensortec, this has no impact to the usage or to the quality of the bm p280 product. 8. appendix 1: computation formulae for 32 bit systems 8.1 compensation formula in floating point please note that it is strongly advised to use the api available from bosch sensortec to perform readout and compensation . if this is not wanted, the code below can be applied at the users risk. both pressure and temperature values are expected to be received in 20 bit forma t, positive, stored in a 32 bit signed integer.
datasheet BMP280 digital pressure sensor page 45 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. the variable t_fine (signed 32 bit) carries a fine resolution temperature value over to the pressure compensation formula and could be implemented as a global variable. the data type BMP280_s32_t should define a 32 bit signed integer variable type and could usually be defined as long signed int. the revision of the code is rev.1.1. // returns temperature in degc, double precision. output value of 51.23 equals 51.23 degc. // t_fine carries fine tempe rature as global value BMP280_s32_t t_fine; double BMP280_compensate_t_double( BMP280_s32_t adc_t) { double var1, var2, t; var1 = ((( double )adc_t)/16384.0 C (( double ) dig_t1)/1024.0) * (( double )dig_t2); var2 = (((( double )adc_t)/131072.0 C (( double )dig_t1)/8192.0) * ((( double )adc_t)/131072.0 C (( double ) dig_t1)/8192.0)) * (( double )dig_t3); t_fine = ( BMP280_s32_t )(var1 + var2); t = (var1 + var2) / 5120.0; return t; } // returns pressure in pa as double. output value of 96386.2 equals 96386.2 pa = 963.862 hpa double BMP280_compensate_p_double( BMP280_s32_t adc_p) { double var1, var2, p; var1 = (( double )t_fine/2.0) C 64000.0; var2 = var1 * var1 * (( double )dig_p6) / 32768.0; var2 = var2 + var1 * (( double )dig_p5) * 2.0; var2 = (var2/4.0)+((( double )dig_p4) * 65536.0); var1 = ((( double )dig_p3) * var1 * var1 / 524288.0 + (( double )dig_p2) * var1) / 524288.0; var1 = (1.0 + var1 / 32768.0)*(( double )dig_p1); if (var1 == 0.0) { return 0; // avoid exception caused by division by zero } p = 1048576.0 C ( double )adc_p; p = (p C (var2 / 4096.0)) * 6250.0 / var1; var1 = (( double )dig_p9) * p * p / 2147483648.0; var2 = p * (( double )dig_p8) / 32768.0; p = p + (var1 + var2 + (( double )dig_p7)) / 16.0; return p; } 8.2 compensation formula in 32 bit fixed point please note that it is strongly advised to use the api available from bosch sensortec to perform readout and compensation. if this is not wanted, the code below can be applied at the users risk. both pressure and temperature values are expected to be received in 20 bit format, positive, stored in a 32 bit signed integer. the variable t_fine (signed 32 bit) carries a fine resolution temperature value over to the pressure compensation formula and could be implemented as a global vari able. the data type BMP280_s32_t should define a 32 bit signed integer variable type and can usually be defined as long signed int. the data type BMP280_u32_t should define a 32 bit unsigned integer variable type and can usually be defined as lon g unsigned int. compensating the pressure value with 32 bit integer has an accuracy of typically 1 pa (1 - sigma). at very high filter levels this adds a noticeable amount of noise to the output values and reduces their resolution. // returns temperatur e in degc, resolution is 0.01 degc. output value of 5123 equals 51.23 degc. // t_fine carries fine temperature as global value BMP280_s32_t t_fine; BMP280_s32_t BMP280_compensate_t_int32( BMP280_s32_t adc_t) { BMP280_s32_t var1, var2, t;
datasheet BMP280 digital pressure sensor page 46 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. var1 = ((((adc_t>>3) C (( BMP280_s32_t )dig_t1<<1))) * (( BMP280_s32_t )dig_t2)) >> 11; var2 = (((((adc_t>>4) C (( BMP280_s32_t )dig_t1)) * ((adc_t>>4) C (( BMP280_s32_t )dig_t1))) >> 12) * (( BMP280_s32_t )dig_t3)) >> 14; t_fine = var1 + var2; t = (t_fine * 5 + 128) >> 8; return t; } // returns pressure in pa as unsigned 32 bit integer. output value of 96386 equals 96386 pa = 963.86 hpa BMP280_u32_t BMP280_compensate_p_int32( BMP280_s32_t adc_p) { BMP280_s32_t var1, var2; BMP280_u32_t p; var1 = ((( BMP280_s32_t )t_fine)>>1) C ( BMP280_s32_t )64000; var2 = (((var1>>2) * (var1>>2)) >> 11 ) * (( BMP280_s32_t )dig_p6); var2 = var2 + ((var1*(( BMP280_s32_t )dig_p5))<<1); var2 = (var2>>2)+((( BMP280_s32_t )dig_p4)<<16); var1 = (((dig_p3 * (((var1>>2) * (var1>>2 )) >> 13 )) >> 3) + (((( BMP280_s32_t )dig_p2) * var1)>>1))>>18; var1 =((((32768+var1))*(( BMP280_s32_t )dig_p1))>>15); if (var1 == 0) { return 0; // avoid exception caused by division by zero } p = ((( BMP280_u32_t )((( BMP280_s32_t )1048576) - adc_p) - (var2> >12)))*3125; if (p < 0x80000000) { p = (p << 1) / (( BMP280_u32_t )var1); } else { p = (p / ( BMP280_u32_t )var1) * 2; } var1 = ((( BMP280_s32_t )dig_p9) * (( BMP280_s32_t )(((p>>3) * (p>>3))>>13)))>>12; var2 = ((( BMP280_s32_t )(p>>2)) * (( BMP280_s32_t )dig_p8))>>13; p = ( BMP280_u32_t )(( BMP280_s32_t )p + ((var1 + var2 + dig_p7) >> 4)); return p; }
datasheet BMP280 digital pressure sensor page 47 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 9. legal disclaimer 9.1 engineering samples engineering samples are marked with an asterisk (*) or (e) or (e) . samples may vary from the valid technical specifications of the product series contained in this data sheet. they are therefore not intended or fit for resale to third parties or for use in end products. their sole purpose is internal client testing. the testing of an engineering sample may in no way replace the testing of a product series. bosch sensortec assumes no liability for the use of engineering samples. the purchaser shall indemnify bosch sensortec from all claims arising from the use of engineering samples. 9.2 product use bosch sensortec pr oducts are developed for the consumer goods industry. they are not designed or approved for use in military applications, life - support appliances, safety - critical automotive applications and devices or systems where malfunctions of these products can reaso nably be expected to result in personal injury. they may only be used within the parameters of this product data sheet. the resale and/or use of products are at the purchasers own risk and the purchasers own responsibility. the purchaser shall indemnify bosch sensortec from all third party claims arising from any product use not covered by the parameters of this product data sheet or not approved by bosch sensortec and reimburse bosch sensortec for all costs in connection with such claims. the purchaser accepts the responsibility to monitor the market for the purchased products, particularly with regard to product safety, and inform bosch sensortec without delay of any security relevant incidents . 9.3 application examples and hints with respect to any example s or hints given herein, any typical values stated herein and/or any information regarding the application of the device, bosch sensortec hereby disclaims any and all warranties and liabilities of any kind, including without limitation warranties of non - in fringement of intellectual property rights or copyrights of any third party. the information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. they are provided for illustrative purposes only and no evalu ation regarding infringement of intellectual property rights or copyrights or regarding functionality, performance or error has been made.
datasheet BMP280 digital pressure sensor page 48 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 10. document history and modification rev. no chapter description of modification/changes date 0.1 document creation 201 2 - 0 8 - 06 u pdate of preliminary versions 1.0 9.2 change of product use 2013 - 11 - 26 table 2 update of min/max data (only for restricted version) added comment on the sampling rate 1.1 1, 3.3.1 changed value for resolution, values for osrs_p settings changed 2014 - 02 - 10 5.2 changed sentence and added drawing 2014 - 02 - 18 3.7 added max values for current consumption 2014 - 05 - 08 1.11 4.5.3 modified write in normal mode 2014 - 06 - 25 5.2 modified sdi/sck esd drawing 1.12 1 changed min/max values for standby current for 25 c 2014 - 07 - 12
datasheet BMP280 digital pressure sensor page 49 bst - BMP280 - ds001 - 10 | revision 1.12 | july 20 14 bosch sensortec ? b osch sensortec gmbh reserves all rights even in the event of industrial property rights. we reserve all rights of disposal su ch as copying and passing on to third parties. bosch and the symbol are registered trademarks of robert bosch gmbh, germany. note: specifications within this document are subject to change without notice. not intended for publication. 1.12 1 changed min/max values for standby current , only valid for 25 c 2014 - 07 - 12 bosch sensortec gmbh gerhard - kindler - strasse 8 72770 reutlingen / germany contact@bosch - sensortec.com www.bosch - sensortec.com modifications reserved | printed in germany specifications subject to change without notice document number: bst - BMP280 - ds001 - 10 revision _ 1.12_072014

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