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[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 1 - 1. general description ak09918 is 3 - axis electronic compass ic with high sensitive hall sensor technology. small package of ak09918 incorporates magnetic sensors for detecting terrestrial magnetism in the x - axis, y - axis, and z - axis, a sensor driving circuit, signal amplifier chain, and an arithmetic circuit for processing th e signal from each sensor. self - test function is also incorpo rated. from its compact foot print and thin package feature, it is suitable for map heading up pu rpose in smart phone to realize pedestrian navigation function. 2. features ? functions: ? 3 - axis magnetometer device suitable for compass application ? built - in a to d converter for magnetometer data out ? 1 6 - bit data out for each 3 - axis magnetic component ? sensitivity: 0. 15 t/lsb ( typ .) ? serial interface ? i 2 c bus interface standard and fast mode s compliant with philips i 2 c specification ver.2.1 ? operation mode ? power - down, single measurement, continuous measurement and self - test ? drdy function for measurement data ready ? magnetic sensor overflow monitor function ? built - in oscillator for internal clock source ? power on reset circuit ? self - test function with internal magnetic source ? built - in magnetic sensitivity adjustment circuit ? operating temperatures: ? - 30 ?c to +85 ?c ? operating supply voltage: ? + 1. 65 v to + 1.95 v ? current consumption: ? power - down: 1 a (typ.) ? measurement: ? avera ge current consumption at 100 hz repetition rate: 1. 1 ma (typ.) ? package: ? ak09918 c 4 - pin wl - csp (bga): 0.8 mm ? 0.8 mm ? 0. 5 mm ak09918 3 - axis electronic compass
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 2 - 3. table of contents 1. general description ................................ ................................ ................................ .................. 1 2. features ................................ ................................ ................................ ................................ ..... 1 3. table of contents ................................ ................................ ................................ ...................... 2 4. block diagram and functions ................................ ................................ ................................ ... 3 5. pin configurations and functions ................................ ................................ ............................. 4 6. absolute maximum ratings ................................ ................................ ................................ ...... 4 7. recommended operating conditions ................................ ................................ ....................... 4 8. electrical characteristics ................................ ................................ ................................ ........... 5 8.1. dc characteristics ................................ ................................ ................................ .............. 5 8.2. ac characteristics ................................ ................................ ................................ .............. 6 8.3. a nalog circuit characteristics ................................ ................................ ............................ 6 8.4. i 2 c bus interface ................................ ................................ ................................ ................ 7 9. function descriptions ................................ ................................ ................................ ............... 8 9.1. power states ................................ ................................ ................................ ....................... 8 9.2. reset functions ................................ ................................ ................................ .................. 8 9.3. operation modes ................................ ................................ ................................ ................ 9 9.4. des cription of each operation mode ................................ ................................ ............... 10 power - down mode ................................ ................................ ................................ .... 10 9.4.1. single measurement mode ................................ ................................ ........................ 10 9.4.2. continuous measurement mode 1, 2, 3 and 4 ................................ ........................... 11 9.4.3. self - test mode ................................ ................................ ................................ ............ 15 9.4.4. 10. serial interface ................................ ................................ ................................ ...................... 16 10.1. i 2 c bus interface ................................ ................................ ................................ ............ 16 data transfer ................................ ................................ ................................ ........... 16 10.1.1. write instruction ................................ ................................ ................................ .. 18 10.1.2. read instruction ................................ ................................ ................................ .... 19 10 .1.3. 11. registers ................................ ................................ ................................ ................................ 20 11.1. description of registers ................................ ................................ ................................ . 20 11.2. register map ................................ ................................ ................................ .................. 21 11.3. detailed description of register ................................ ................................ .................... 22 wia: who i am ................................ ................................ ................................ ...... 22 11.3.1. rsv: reserved register ................................ ................................ ............................ 22 11.3.2. st1: status 1 ................................ ................................ ................................ ............ 22 11.3.3. hxl to hzh: measurement data ................................ ................................ ............ 23 11.3.4. tmps: dummy register ................................ ................................ ........................... 23 11.3.5. st2: status 2 ................................ ................................ ................................ ............ 24 11.3.6. cntl1: dummy register ................................ ................................ ......................... 24 11.3.7. cntl2: control 2 ................................ ................................ ................................ .... 24 11.3.8. cntl3: control 3 ................................ ................................ ................................ .... 25 11.3.9. ts1, ts2: test register ................................ ................................ ........................... 25 11.3.10. 12. example of recommended external connection ................................ ................................ . 26 13. package ................................ ................................ ................................ ................................ . 27 13.1. marking ................................ ................................ ................................ .......................... 27 13.2. pin assignment ................................ ................................ ................................ ............... 27 13.3. outline dimensions ................................ ................................ ................................ ........ 28 13.4 . recommended foot print pattern ................................ ................................ ................... 28 14. relationship between the magnetic field and output code ................................ ................. 29 important notice ................................ ................................ ................................ .............. 30
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 3 - 4. block dia gram and f unctions block function 3 - axis hall sensor monolithic hall elements. mux multiplexer for selecting hall elements. chopper sw performs chopping. he - drive magnetic sensor drive circuit. pre - amp fixed - gain differential amplifier used to amplify the magnetic sensor signal. integrator & adc integrates and amplifies p re - amp output and performs analog - to - digital conversion. osc generates an operating clock for sensor measurement. por power on reset circuit. generates reset signal on rising edge of vdd. vref generates reference voltage and current. interface logic & register exchanges data with an external cpu. i 2 c bus interface using two pins, namely, scl and sda. standard and fast mode s are supported. timing control generates a timing signal required for internal operation from a clock generated by the osc. magnetic source generates magnetic field for s elf - test of magnetic sensor. 3 - axis hall sensor mux sda chopper sw he - drive pre - amp integrator adc interface logic & register scl vdd vref timing control osc magnetic source vss por
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 4 - 5. pin configurations and function s pin no. pin name i/o type function a1 vss - - ground pin. a 2 scl i cmos control data clock input pin. input: schmidt trigger b1 vdd - power positive power supply pin. b 2 s da i /o cmos control data input/output pin. input: schmidt trigger, output: open - drain 6. absolute maximum ratings vss = 0v parameter symbol min . max . unit power supply voltage v dd - 0.3 + 2.5 v input voltage (except for power supply pin) v in - 0.3 + 2.5 v input current (except for power supply pin) i in - 10 ma storage temperature t st - 40 +125 ?c if the device is used in conditions exceeding these values, the device may be destroyed. normal operations are not guaranteed in such exceeding conditions. 7. recommended operating conditions vss = 0v parameter symbol min. typ. max. unit operating temperature ta - 30 +85 ?c power supply voltage vdd 1. 65 1.8 1.95 v
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 5 - 8. electrical characteristics the following conditions apply unless otherwise noted: vdd = 1. 65 v to 1.95 v, temperature range = - 30 ?c to + 85 ?c . 8.1. dc characteristics parameter symbol pin condition min. typ. max. unit high level input voltage vih scl sda 70%v d d v low level input voltage vil scl sda - 0.3 30%v d d v input current iin scl sda v in = vss or v d d - 10 +10 a hysteresis input voltage (note 1) vhs scl sda 10%vdd v low level output voltage (note 2) vol sda iol +3ma 20%vdd v current consumption (note 3) idd1 vdd power - down mode vdd = 1.95v 1 3 a idd2 when magnetic sensor is driven 1 . 5 3 ma idd3 self - test mode 2.5 4 ma (note 1) schmitt trigger input (reference value for design) (note 2) output is o pen - drain. connect a pull - up resistor externally . maximum capacitive load: 400pf (capacitive load of each bus line for i 2 c bus interface). (note 3) without any resistance load . it does not include the current consumed by external loads (pull - down resister, etc.). s da = scl = vdd or 0v.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 6 - 8.2. ac characteristics parameter symbol pin condition min. typ. max. unit power supply rise time (note 4) psup vdd period of time that vdd changes from 0.2v to vdd. 50 ms por completion time (note 4) port period of time after psup to power - down mode (note 5) 100 s power supply turn off voltage (note 4) sdv vdd turn off voltage to enable por to restart (note 5) 0.2 v power supply turn on interval (note 4) psint vdd period of time that voltage lower than sdv needed to be kept to enable por to restart (note 5) 100 s wait time before mode setting twa i t 100 s (note 4) reference value for design . (note 5) when por circuit detects the rise of vdd voltage, it resets internal circuits and initializes the registers. after reset, ak09918 transits to power - down mode. 8.3. analog circuit characteristics parameter symbol condition min. typ. max. unit measurement data output bit dbit - 1 6 - b it time for measurement tsm single measurement mode 7.2 8. 2 ms magnetic sensor sensitivity bse t a = 25 ?c 0. 1425 0. 15 0. 1575 t/lsb magnetic sensor measurement range (note 6) brg t a = 25 ?c 4 670 4912 5160 t magnetic sensor initial offset (note 7) bio t a = 25 ?c - 20 00 + 20 00 lsb (note 6) reference value for desig n (note 7) value of measurement data register on shipment test without applying magnetic field on purp ose. 0v psint psup port power - down mode sdv vdd powe r - down mode
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 7 - 8.4. i 2 c bus interface i 2 c bus interface is compliant with standard mode and fast mode. standard/fast mode is selected automatically by fscl. ? standard mode fscl 100khz symbol parameter min. typ. max. unit fscl scl clock frequency 100 khz thigh scl clock high time 4.0 ? s tlow scl clock low time 4.7 ? s tr sda and scl rise time 1.0 ? s tf sda and scl fall time 0.3 ? s thd:sta start condition hold time 4.0 ? s tsu:sta start condition setup time 4.7 ? s thd:dat sda hold time (vs. scl falling edge) 0 ? s tsu:dat sda setup time (vs. scl rising edge) 250 ns tsu:sto stop condition setup time 4.0 ? s tbuf bus free time 4.7 ? s ? fast mode 100 k hz fscl 400khz symbol parameter min. typ. max. unit fscl scl clock frequency 400 khz thigh scl clock high time 0.6 ? s tlow scl clock low time 1.3 ? s tr sda and scl rise time 0.3 ? s tf sda and scl fall time 0.3 ? s thd:sta start condition hold time 0.6 ? s tsu:sta start condition setup time 0.6 ? s thd:dat sda hold time (vs. scl falling edge) 0 ? s tsu:dat sda setup time (vs. scl rising edge) 100 ns tsu:sto stop condition setup time 0.6 ? s tbuf bus free time 1.3 ? s tsp noise suppression pulse width 50 ns [i 2 c bus interface timing] scl vih vil 1/fscl thigh scl s da v ih tlow tbuf thd:sta tr tf thd:dat tsu:dat tsu:sta stop start start stop tsu:sto v il v ih v il tsp
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 8 - 9. function descriptions 9.1. power states when vdd is turned on from vdd = off (0v), all registers in ak09918 are initialized by por circuit and ak09918 transits to power - down mode. table 9.1. p ower state state vdd power state 1 off (0v) off it doesnt affect external interface. 2 1. 65 v to 1.95 v on 9.2. reset functions power on r eset (por) works until vdd reaches to the operation effective voltage (about 1.1v: reference value for design) on power - on sequence. after por is completed , all registers are initialized and ak09918 transits to p ower - down mode. when vdd = 1. 65 to 1.95 v, por circuit is active. ak09918 has t wo types of reset; (1) power on r eset (por) when vdd rise is detected, por circuit operates, and ak09918 is reset. (2) soft reset ak09918 is reset by setting srst bit. when ak09918 is reset, all registers are initialized and ak09918 transits to power - down mode.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 9 - 9.3. operation modes ak09918 has following seven operation modes: (1) power - down mode (2) single measurement mode (3) continuous measurement mode 1 (4) continuous measurement mode 2 (5) continuous measurement mode 3 (6) continuous measurement mode 4 (7) self - test mode by setting cntl2 register mode[4:0] bits, the operation set for each mode is started. a transition from one mode to another is sho wn below. figure 9.1. operation mode when power is turned on, ak09918 is in power - down mode. when a specified value is set to mode[4:0] bits , ak09918 transits to the specified mode and starts operation. when user wants to change operation mode, transit to power - down mode first and then transit to other modes. after power - down mode is set, at least 100 ? s (twa i t) is needed before setting another mode mode[ 4 :0] = 00 0 0 1 mode[ 4 :0 ] = 0000 0 transits automatically mode[ 4 :0] = 00 010 mode[ 4 :0] = 00 00 0 mode[ 4 :0] = 0 0100 mode[ 4 :0] = 0 00 00 mode[ 4 :0] = 0 0 11 0 mode[ 4 :0] = 0 0 00 0 mode[ 4 :0] = 0 1 000 mode[ 4 :0] = 0 0000 mode[ 4 :0] = 1 0 000 mode[ 4 :0] = 0 0 000 transits automatically power - down mode continuous measurement mode 2 sensor is measured periodically in 20hz. transits to pow er - down mode by writing mode[ 4 :0] =00 0 00 . self - test mode sensor is self - t ested and the result is output. transits t o power - down mode automatically. single measurement mode sensor is measured for one time and data is output. transits to power - down mode au tomatically after measurement ended. continuous measurement mode 1 sensor is measured periodically in 10hz. transit s to power - down mode by writing mode[ 4 :0] = 0000 0 . continuous measurement mode 3 sensor is measured periodically in 50hz. transit s to power - down mode by writing mode[ 4 :0] = 00 0 00 . continuous measurement mode 4 sensor is measured periodically in 100hz. transits t o power - down mode by writing mode[ 4 :0] = 00 0 00 .
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 10 - 9.4. description of each operation mode power - down mode 9.4.1. power to almost all internal circuits is turned off. all registers are accessible in p ower - down mode. data stored in read/write registers are remained. they can be reset by soft reset. single measurement mode 9.4.2. when s ingle measurement mode (mode[4:0] bits = 00001 ) is set, magnetic sensor measurement is started . a fter magnetic sensor measurement and signal processing is finished, measurement magnetic data is stored to measurement data registers (hxl to hzh), then ak09918 transits to p ower - down mode automatically. on trans ition to p ower - down mode, mode[4 :0] bits turns to 0 0000 . at the same time, drdy bit in st1 register turns to 1 . this is called d ata ready . when any of measu rement data register (hxl to tmps ) or st2 register is read, drdy bit turns to 0 . it remains 1 on transition from power - down mode to another mode. ( figure 9.2. ) when sensor is measuring (measurement period), measurement data registers (hxl to tmps) keep the previous data. therefore, it is possible to read out data even in measurement period. data re ad out in measurement period are previous data. ( figure 9.3. ) figure 9.2. single measurement mode when data is read out of measurement period figure 9.3. singl e measurement mode when data read started during measurement period operation mode: single measuremnet power-down (1) (2) (3) measurement period internal buffer last data measurement data (1) data(2) data(3) measurement data register last data measurement data (1) data(3) drdy data read data(1) data(3) register write mode[4:0]="00001" mode[4:0]="00001" mode[4:0]="00001" operation mode: single measuremnet power-down (1) (2) (3) measurement period internal buffer last data measurement data (1) data(2) data(3) measurement data register last data measurement data (1) drdy data read data(1) register write mode[4:0]="00001" mode[4:0]="00001" mode[4:0]="00001"
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 11 - continuous measurement mode 1, 2, 3 and 4 9.4.3. when c ontinuous measurement mode 1 (mode[4:0] bits = 00010 ), 2 (mode[4:0] bits = 00100 ), 3 (mode[4:0] bits = 0 0110 ) or 4 (mode[4:0] bits = 01000 ) is set, magnetic sensor measurement is start ed periodically at 10 hz, 20 hz, 50 hz or 100 hz respectively. after magnetic sensor measurement and signal processing is finished, measurement magnetic data is stored to m easurement data registers (hxl to hzh) and all circuits except for the minimum circuit required for counting cycle leng t h are turned off (pd). when the next measurement timing comes, ak09918 wakes up automatically from pd and starts measurement again. continuous measurement mode ends when p ower - down mode (mode[4:0] bits = 00000 ) is set. it repeats measurement until p ower - down mode is set. when c ontinuous measurement mode 1 (mode[4:0] bits = 00010 ), 2 (mode[4:0] bits = 00100 ), 3 (mode[4:0] bits = 00110 ) or 4 (mode[4:0] bits = 01000 ) is set again while ak09918 is already in c ontinuous measurement mode, a new measurement starts. st1, st2 and measurement data registers (hxl to t mps ) will not be initialized by this. figure 9.4. continuous measurement mode 9.4.3.1. data ready when measurement data is stored and ready to be read, drdy bit in st1 register turns to 1 . this is called data ready . when measuremen t is performed correctly , ak09918 becomes data ready on transition to pd after measurement. (n-1)th nth (n+1)th pd measurement pd measurement pd 10hz,20hz,50hz or 100hz
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 12 - 9.4.3.2. normal read sequence (1) check data ready or not by p olling drdy bit of st1 register ? drdy: shows data ready or not. not when 0 , data ready when 1 . ? dor: shows if any data has been skipped before the current data or not. there are no skipped data when 0 , there are skipped data when 1 . (2) read measurement data when any of meas urement data register (hxl to tmps) or st2 register is read, ak09918 judges t hat data reading is started. when data reading is started, drdy bit and dor bit turns to 0 . (3) read st2 register (required) ? hofl: shows if magnetic sensor is overflowed or not. 0 means not overflo w ed, 1 means overflowed. when st2 register is read, ak09918 judges that data reading is finished. stored measurement data is protected during data reading and data is not updated. by reading st2 register, this protection is released. it is required to read st2 register after data reading. figure 9.5. normal read sequence 9.4.3.3. data read start d uring measurement when sensor is measuring (measurement period), measurement data registers (hxl to tmps) keep the previous data. therefore, it is possible to read out data even in measurement period. if data is started to be read during measurement period, previous data is read. figure 9.6. data read start during measurement (n-1)th nth (n+1)th pd measurement pd measurement pd internal buffer (n-1)th nth (n+1)th measurement data register (n-1)th nth (n+1)th drdy data read st1 data(n) st2 st1 data(n+1) st2 (n-1)th nth (n+1)th pd measurement pd measurement pd internal buffer (n-1)th nth (n+1)th measurement data register (n-1)th nth drdy changes to "1" because read-out becomes possible. drdy data read st1 data(n) st2 st1 data(n) st2
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 13 - 9.4.3.4. data skip when nth data was not read before (n+1)th measurement ends, data ready remains until data is read. in this case, a set of measurement data is skipped so that dor bit turns to 1 . when data reading started after nth measurement ended and did not finish rea ding before (n+1)th measurement ended, nth measurement data is protected to keep correct data. in this case, a set of measurement data is skipped and not stored so that dor bit turns to 1 . in both case, dor bit turns to 0 at the next start of data read ing. figure 9.7. data skip: when data is not read figure 9.8. data skip: when data read has not been finished before the next measurement end (n-1)th nth (n+1)th pd measurement pd measurement pd internal buffer (n-1)th nth (n+1)th measurement data register (n-1)th (n+1)th drdy dor data read st1 data(n+1) st2 (n-1)th nth (n+1)th (n+2)th pd measurement pd measurement pd measurement pd internal buffer (n-1)th nth (n+1)th (n+2)th measurement data register (n-1)th nth (n+2)th data register is protected because data is being read drdy changes to "1" because read-out becomes possible. drdy (n+1)th data is skipped dor data read st1 data(n) st2 st1 data(n+2)
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 14 - although nth data is read out when it is performed during (n+1)th measurement period, (n+1)th data is obtained by reading out again before completion of (n+2)th measurement. f i gure 9.9. read - out is performed before completion of the next measurement after data protection. 9.4.3.5. end operation set p ower - down mode (mode[4:0] bits = 00000 ) to end c ontinuous measurement mode. 9.4.3.6. magnetic sensor overflow ak09918 has the limitation for measurement range that the sum of absolute values of each axis should be smaller than 4912 t . (note 8) |x|+|y|+|z| < 4912 t when the magnetic field exceeded this limitation, data stored at measurement data are not correct. this is called magnetic sensor overflow. when magnetic sensor over f low occurs, hofl bit turns to 1 . when measurement data register (hxl to hzh) is updated, h ofl bit is updated. (note 8) brg: 0.15 t /lsb (n-1)th nth (n+1)th (n+2)th pd measurement pd measurement pd measurement pd internal buffer (n-1)th nth (n+1)th (n+2)th measurement data register (n-1)th nth (n+1)th data register is protected because data is being read drdy changes to "1" because read-out becomes possible. drdy dor data read st1 data(n) st2 st1 data(n+1)
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 15 - self - test mode 9.4.4. self - test mode is used to check if the magnetic sensor is working normally. when s elf - test mode (mode[4:0] bits = 10000 ) is set, magnetic field is generated by the internal magnetic source and magnetic sensor is measured. measurement data is stored to measurement data registers (hxl to hzh), then ak09918 transits to p ower - down mode automatically. data read sequence and fun ctions of read - only registers in s elf - test mode is the same as s ingle measurement mode. 9.4.4.1. self - test s equence (1) set power - down mode. (mode[4:0] bits = 00000 ) (2) set self - test m ode. (mode[4:0] bits = 10000 ) (3) check data ready or not by p olling drdy bit of st1 register . when data ready, proceed to the next step. (4) read measurement data . (hxl to hzh) 9.4.4.2. self - test judgment when measurement data read by the above sequence is in the range of following table, ak09918 is working normally. hx[15:0] bits hy[15:0] bits hz[15:0] bits criteria - 200 hx 200 - 200 h y 200 - 1000 h z - 150
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 16 - 10. serial interface 10.1. i 2 c bus interface the i 2 c bus interface of ak09918 supports the s tandard mode (100 khz max.) and the f ast mode (400 khz max.) . data transfer 10.1.1. to access ak09918 on the bus, generate a start condition first. next, transmit a one - byte slave address including a device address. at this time, ak09918 compares the slave address with its own address. if these addresses match, ak09918 generates an acknow ledgement, and then executes read or write instruction. at the end of instruction execution, generate a stop condition. 10.1.1.1. change of data a change of data on the sda line must be made during low period of the clock on the scl line. when the clock signal on the scl line is high , the state of the sda line must be stable. (data on the sda line can be changed only when the clock signal on the scl line is low .) during the scl line is high , the state of data on the sda line is changed only when a start cond ition or a stop condition is generated. figure 10.1. data change 10.1.1.2. start/stop condition if the sda line is driven to low from high when the scl line is high , a start condition is generated. every instruction starts with a start condition. if the sda line is dri ven to high from low when the scl line is high , a stop condition is generated. every instruction stops with a stop condition. figure 10.2. start and stop condit i on scl sda stop condition start condition scl sda data line stable : data valid change of data allowed
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 17 - 10.1.1.3. acknowledge the ic that is transmitting data releases the sda line (in the high state) after sending 1 - byte data. the ic that receives the data drives the sda line to low on the next clock pulse. this operation is referred as acknowledge. with this operation, whether data has been transferred successfully can be checked. ak09918 generates an acknowledge after reception of a start condition and slave address. when a write instruction is executed, ak09918 generates an acknowledge after every byte is received. when a read instruction is executed, ak09918 generates an acknowledge then transfers the data stored at the specified address. next, ak09918 releases the s da line then monitors the sda line. if a master ic generates an acknowledge instead of a stop condition, ak09918 transmits the 8bit data stored at the next address. if no acknowledge is generated, ak09918 stops data transmission. figure 10.3. generatio n of acknowledge 10.1.1.4. slave address the slave address of ak09918 is 0ch. msb lsb 0 0 0 1 1 0 0 r/w figure 10.4. slave address the first byte including a slave address is transmitted after a start condition, and an ic to be accessed is selected from the ics on the bus according to the slave address. when a slave address is transferred, the ic whose device address matches the transferred slave address generates an acknowledge then executes an i nstruction. the 8th bit (least significant bit) of the first byte is a r/w bit. when the r/w bit is set to 1 , read instruction is executed. when the r/w bit is set to 0 , write instruction is executed. scl from master acknowledge data output by transmitter data output by receiver 1 9 8 start condition clock pulse for acknowledge not acknowledge
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 18 - write instruction 10.1.2. when the r/w bit is set to 0 , ak09918 performs write operation. in write operation, ak09918 generates an acknowledge after receiving a start condition and the first byte (slave address) then receives the second byte. the second byte is used to specify the address of an internal control register and is based on the msb - first configuration. msb lsb a7 a6 a5 a4 a3 a2 a1 a0 figure 10.5. register address after receiving the second byte (register address), ak09918 generates an acknowledge then receives the third byte. the third and the following bytes represent control data. control data consists of 8 bits and is based on the msb - first configuration. ak09918 generates an acknowledge after every byte is received. data transfer al ways stops with a stop condition generated by the master. msb lsb d7 d6 d5 d4 d3 d2 d1 d0 figure 10.6. control data ak09918 can write multiple bytes of data at a time. after reception of the third byte (control data), ak09918 generates an acknowledge then receives the next data. if additional data is received instead of a stop condition after receiving one byte of data, the address counter inside the lsi chip is automati cally incremented and the data is written at the next address. the address is incremented from 00 h to 18 h , from 30 h to 3 2 h . when the address is 00 h to 18 h , the address is incremented 00 h ? 01 h ? 02 h ? 03 h ? 10 h ? 11 h ? ... ? 18 h ,and the address goes back to 00 h after 18h. when the address is 30 h to 32 h , the address goes back to 30 h after 32 h . actual data is written only to read/write registers ( table 11.2. ) . figure 10.7. write instruction sda s t a r t a c k a c k s slave address a c k register address(n) data(n) p s t o p data(n+x) a c k data(n+1) a c k a c k r/w= " 0 "
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 19 - read instruction 10.1.3. when the r/w bit is set to 1 , ak09918 performs read operation. if a master ic generates an acknowledge instead of a stop condition after ak09918 transfers the data at a specified address, the data at the next address can be read. address can be 00 h to 18 h , 30 h to 32 h . when the address is 00 h to 18 h , the address is incremented 00 h ? 01 h ? 02 h ? 03 h ? 10 h ? 11 h ? ... ? 18 h , and the address goes back to 00 h after 18 h . when the address is 3 0 h to 32 h , the address goes back to 30 h after 32 h . ak09918 supports current address read and random address read. 10.1.3.1. current address read ak09918 has an address counter inside the lsi chip. in current address read operation, the data at an address specified by this counter is read. the internal address counter holds the next address of the most recently accessed address. for example, if the address most recently accessed (for read instruction) is address n , and a current address read operation is attempted, the data at address n+1 is read. in current address read operation, ak09918 generates an acknowledge after receiving a slave address for the read instruction (r/w bit = 1 ). next, ak09918 transfers the data specified by the internal address counter starting with the next clock pulse, then increments the internal counter by one. if the master ic generates a stop condition instead of an acknowl edge after ak09918 transmits one byte of data, the read operation stops. figure 10.8. current address read 10.1.3.2. random address read by random address read operation, data at an arbitrary address can be read. the random address read operation requires to execute write instruction as dummy before a slave address for the read instruction (r/w bit = 1 ) is transmitted. in random read operation, a start condition is first generated then a slave address for the write instruction (r/ w bit = 0 ) and a read address are transmitted sequentially. after ak09918 generates an acknowledge in response to this address transmission, a start condition and a slave address for the read instruction (r/w bit = 1 ) are generated again. ak09918 generates an acknowledge in response to this slave address transmission. next, ak09918 transfers the data at the specified address then increments the internal address counter by one. if the master ic generates a stop condition instead of an acknowledge a fter data is transferred, the read operation stops. figure 10.9. random address read sda s t a r t a c k a c k s slave address a c k data(n +1 ) d ata(n+2 ) p s t o p data(n+x) a c k d ata(n+3 ) a c k r/w= " 1 " sda s t a r t a c k a c k s slave address a c k register address(n) data(n) p s t o p data(n+x) a c k data(n+1) a c k r/w= " 0 " s t a r t a c k s slave address r/w= " 1 "
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 20 - 11. registers 11.1. description of registers ak09918 has registers of 1 8 addresses as indicated in table 11.1. . every address consists of 8 bits data. data is transferred to or received from the external cpu via the serial interface described previously. table 11.1. register table name address read/ write description bit width remarks wia 1 00 h read c o mpany id 8 wia2 01 h read device id 8 rsv 1 02 h read reserved 1 8 rsv 2 03 h read reserved 2 8 st1 10 h read status 1 8 data status hxl 11 h read measur e ment magnetic data 8 x - axis data hxh 12 h read 8 hyl 13 h read 8 y - axis data hyh 14 h read 8 hzl 15 h read 8 z - axis data hzh 16 h read 8 tmps 17 h read dummy 8 dummy st2 18 h read status 2 8 data status cntl1 30 h read/ write dummy 8 dummy cntl2 31 h read/ write control 2 8 control settings cntl3 32 h read/ write control 3 8 control settings ts1 33 h read/ write test 8 do not access ts2 34h read/ write test 8 do not access addresses 00 h to 18 h , 30 h to 32 h are compliant with automatic increment function of serial interface respectively. in other modes, read data is not correct . w hen the address is in 00 h to 18 h , the address is incremented 00 h ? 01 h ? 02 h ? 03 h ? 10 h ? 11 h ? ... ? 18 h , and the address goes ba ck to 00 h after 18 h . when the address is in 30 h to 32 h , the address goes back to 30 h after 32 h .
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 21 - 11.2. register map table 11.2. register map addr. register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 00 h wia1 0 1 0 0 1 0 0 0 01 h wia2 0 0 0 0 1 1 0 0 02 h rsv 1 rsv 1 7 rsv 1 6 rsv 1 5 rsv 1 4 rsv 1 3 rsv 1 2 rsv 1 1 rsv 1 0 03 h rsv 2 rsv 2 7 rsv 2 6 rsv 2 5 rsv 2 4 rsv 2 3 rsv 2 2 rsv 2 1 rsv 2 0 10 h st1 0 0 0 0 0 0 dor drdy 11 h hxl hx7 hx6 hx5 hx4 hx3 hx2 hx1 hx0 12 h hxh hx15 hx14 hx13 hx12 hx11 hx10 hx9 hx8 13 h hyl hy7 hy6 hy5 hy4 hy3 hy2 hy1 hy0 14 h hyh hy15 hy14 hy13 hy12 hy11 hy10 hy9 hy8 15 h hzl hz7 hz6 hz5 hz4 hz3 hz2 hz1 hz0 16 h hzh hz15 hz14 hz13 hz12 hz11 hz10 hz9 hz8 17 h tmps 0 0 0 0 0 0 0 0 18 h st2 0 rsv3 1 rsv 30 rsv2 9 hofl rsv28 0 0 read/writ e register 30 h cntl1 0 0 0 0 0 0 0 0 31 h cntl2 0 0 0 mode4 mode3 mode2 mode1 mode0 32 h cntl3 0 0 0 0 0 0 0 srst 33 h ts1 - - - - - - - - 34h ts2 - - - - - - - - when vdd is turned on, por function works and all registers of ak09918 are initialized. ts1 and ts2 are test register s for shipment test. do not access these register s .
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 22 - 11.3. detailed description of register wia: who i am 11.3.1. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 00 h wia 1 0 1 0 0 1 0 0 0 01 h wia2 0 0 0 0 1 1 0 0 wia1 [7:0] bits : company id of akm. it is described in one byte and fixed value. 48 h : fixed wia2 [7:0] bits : device id of ak09918 . it is described in one byte and fixed value. 0 c h : fixed rsv : reserved 11.3.2. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 02 h rsv 1 rsv 1 7 rsv 1 6 rsv 1 5 rsv 1 4 rsv 1 3 rsv 1 2 rsv 1 1 rsv 1 0 03 h rsv 2 rsv 2 7 rsv 2 6 rsv 2 5 rsv 2 4 rsv 2 3 rsv 2 2 rsv 2 1 rsv 2 0 rsv 1[7:0] bits / rsv 2[7:0] bits : reserved register for akm. st1: status 1 11.3.3. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 10 h st1 0 0 0 0 0 0 dor drdy reset 0 0 0 0 0 0 0 0 drdy: data ready 0 : normal 1 : data is ready drdy bit turns to 1 when data is ready in s ingle measurement mode, c ontinuous measurement mode 1, 2, 3, 4 or s elf - test mode. it returns to 0 when any one of st2 register or measurement data register (hxl to tmps ) is read. dor: data overrun 0 : normal 1 : data overrun dor bit turns to 1 when data has been skipped in c ontinuous measurement mode 1, 2, 3, 4. it returns to 0 when any one of st2 register or measurement data register (hxl to tmps) is read.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 23 - hxl to hzh: measurement magnetic data 11.3.4. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 11 h hxl hx7 hx6 hx5 hx4 hx3 hx2 hx1 hx0 12 h hxh hx15 hx14 hx13 hx12 hx11 hx10 hx9 hx8 13 h hyl hy7 hy6 hy5 hy4 hy3 hy2 hy1 hy0 14 h hyh hy15 hy14 hy13 hy12 hy11 hy10 hy9 hy8 15 h hzl hz7 hz6 hz5 hz4 hz3 hz2 hz1 hz0 16 h hzh hz15 hz14 hz13 hz12 hz11 hz10 hz9 hz8 reset 0 0 0 0 0 0 0 0 measurement data of magnetic sensor x - axis/y - axis/z - axis hxl[7:0] bits : x - axis measurement data lower 8 - bit hxh[15:8] bits : x - axis measurement data higher 8 - bit hyl[7:0] bits : y - axis measurement data lower 8 - bit hyh[15:8] bits : y - axis measurement data higher 8 - bit hzl[7:0 ] bits : z - axis measurement data lower 8 - bit hzh[15:8] bits : z - axis measurement data higher 8 - bit measurem e nt data is stored in twos complement and little endian format. measuremen t range of each axis is - 32752 to 32752 in 16 - bit output . table 11.3. measurement magnetic data format measurement data (each axis) [15:0] bits magnetic flux density [ ] twos complement hex decimal 0 11 1 1111 1111 000 0 7 ff 0 32752 4912(max.) | | | | 0000 0000 0000 0001 0001 1 0. 15 0000 0000 0000 0000 0000 0 0 1111 1111 1111 1111 ffff - 1 - 0. 15 | | | | 1 00 0 0000 000 1 0 0 0 0 8010 - 32752 - 4912(min.) tmps: dummy 11.3.5. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 17 h tmps 0 0 0 0 0 0 0 0 reset 0 0 0 0 0 0 0 0 tmps[7:0] bits: dummy register.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 24 - st2: status 2 11.3.6. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read - only register 18 h st2 0 rsv3 1 rsv 30 rsv2 9 hofl rsv28 0 0 reset 0 0 0 0 0 1 0 0 st 2[ 6 : 4 ] bits: reserved register for akm. hofl: magnetic sensor overflow 0 : normal 1 : magnetic sensor overflow occurred in s ingle measurement mode, c ontinuous measurement mode 1, 2, 3, 4, and s elf - test mode, magnetic sensor may overflow even though measurement data register is not saturated. in this case, measurement data is not correct and hofl bit turns to 1 . when measurement data register is updated, hofl bit is updated. refer to 9.4.3.6 for detailed information. st2 register has a role as data reading end register, also. when any of measurement data register (hxl to tmps) is read in c ontinuous measurement mode 1, 2, 3, 4, it means data reading start and taken as data reading until st2 register is read. therefore, when any of measurement data is read, be sure to read st2 register at the end. cntl1: dummy 11.3.7. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read /write register 30 h cntl1 0 0 0 0 0 0 0 0 reset 0 0 0 0 0 0 0 0 cntl1[7:0] bits: dummy register. cntl2: control 2 11.3.8. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read/write register 31 h cntl2 0 0 0 mode4 mode3 mode2 mode1 mode0 reset 0 0 0 0 0 0 0 0 mode[4:0] bits : operation mode setting 00000 : power - down mode 00001 : single measurement mode 00010 : continuous measurement mode 1 00100 : continuous measurement mode 2 00110 : continuous measurement mode 3 01000 : continuous measurement mode 4 10000 : self - test mode other code settings are prohibited . when each mode is set, ak09918 transits to the set mode. refer to 9.3 for detailed information.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 25 - cntl3: control 3 11.3.9. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read/write register 32 h cntl3 0 0 0 0 0 0 0 srst reset 0 0 0 0 0 0 0 0 srst: soft reset 0 : normal 1 : reset when 1 is set, all registers are initialized. after reset, srst bit turns to 0 automatically. ts1 , ts2 : test 11.3.10. addr . register name d7 d6 d5 d4 d3 d2 d1 d0 read/write register 33 h ts1 - - - - - - - - 34h ts2 - - - - - - - - reset 0 0 0 0 0 0 0 0 ts1 and ts2 register s are akm internal test register. do not access these register s .
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 26 - 12. example of recommended external connection ak09918 c (top view) host cpu i 2 c i/f power for i/f vdd power 1.65 v to 1.95 v 0.1f 2 1 b a scl sda vss vdd
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 27 - 13. package 13.1. marking date code: x 1 x 2 x 3 x 4 x 5 ? x1 = id ? x2 = year code ? x3 =month code ? x4x5 =lot 13.2. pin assignment 2 1 b sda vdd a scl vss x 1 x 2 x 3 x 4 x 5
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 28 - 13.3. outline dimensions [mm] 13.4. recommended foot print pattern [mm] 0 .03 c 0.583 max. 0.40 0.147 0.4 0.4 +0.03 0.22 - 0.01 2 1 0.76 ? 0.03 0.76 ? 0.03 b a 1 2 c b a 0 . 4 0. 4 0.21 2 1 b a
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 29 - 14. relations h ip between the magnetic field and output code the measurement data increases as the magnetic flux density increases in the arrow directions.
[ ak09918 ] 016014242 - e - 0 0 20 1 6 / 11 - 30 - important notice 0. asahi kasei microdevices corporation (akm) reserves the right to make changes to the information contained in this document without notice. when you consider any use or application of akm product stipulated in this document ( product ) , please make inquiries the sales office of akm or authorized d istributor s as to current status of the products. 1. all information included in this document are provided only to illustrate the operation and application examples of akm products . akm neither makes warranties or representations with respect to the accuracy or completeness of the information contained in this document nor grants any license to any intellectual property rights or any other rights of akm or any third party with respect to the information in this document. you are fully responsible for use of such information contained in this document in your product design or applications . akm assumes no liability for any losses incurred by you or third parties arising from the use of such information in your product design or applications. 2. the product is neither intended nor warranted for use in equipment or systems that require extraordinarily high levels of quality and/or reliability and/or a malfunction or failure of which may c ause loss of human life, bodily injury, serious property damage or serious public impact , including but not limited to, equipment used in nuclear facilities, equipment used in the aerospace industry, medical equipment, equipment used for automobiles, train s, ships and other transportation, traffic signaling equipment, equipment used to control combustions or explosions, safety devices, elevators and escalators, devices related to electric power, and equipment used in finance - related fields. do not use produ ct for the above use unless specifically agreed by akm in writing . 3. though akm works continually to improve the products quality and reliability, you are responsible for complying with safety standards and for providing adequate designs and safeguards f or your hardware, software and systems which minimize risk and avoid situations in which a malfunction or failure of the product could cause loss of human life, bodily injury or damage to property, including data loss or corruption. 4. do not use or otherw ise make available the product or related technology or any information contained in this document for any military purposes, including without limitation, for the design, development, use, stockpiling or manufacturing of nuclear, chemical, or biological w eapons or missile technology products (mass destruction weapons). when exporting the p roducts or related technology or any information contained in this document, you should comply with the applicable export control laws and regulations and follow the proc edures required by such laws and regulations. the p roducts and related technology may not be used for or incorporated into any products or systems whose manufacture, use, or sale is prohibited under any applicable domestic or foreign laws or regulations. 5. please contact akm sales representative for details as to environmental matters such as the rohs compatibility of the product. please use the product in compliance with all applicable laws and regulations that regulate the inclusion or use of controlled substances, including without limitation, the eu rohs directive. akm assumes no liability for damages or losses occurring as a result of noncompliance with applicable laws and regulations. 6. resale of the product with provisions different from the statem ent and/or technical features set forth in this document shall immediately void any warranty granted by akm for the product and shall not create or extend in any manner whatsoever , any liability of akm. 7. this document may not be reproduced or duplicated, in any form, in whole or in part, without prior written consent of akm . rev.1

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