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mpr083 rev 4, 10/2008 freescale semiconductor technical data preliminary ? freescale semiconductor, inc., 2007, 2008. all rights reserved. this document contains a product under development. freescale semiconducto r reserves the right to change or discontinue this product without notice. product preview proximity capacitive touch sensor controller mpr083 overview the mpr083 is an inter-integrated circuit communication (i 2 c) driven capacitive touch sensor controller, optimized to manage an 8-position rotary shaped capacitive array. the device can accommodate a wide range of implementations throug h 3 output mechanisms, and many configurable options. features ? 1.8 v to 3.6 v operation ? 41 a average supply current with 1 s response time ? 2 a standby current ? variable low power mode response time (32 ms ? 4 s) ? rejects unwanted multi-key detections from emi events such as pa bursts or user handling ? ongoing pad analysis and detection is not reset by emi events ? data is buffered in a fifo for shortest access time ?irq output advises when fifo has data ? system can set interrupt behavior as immediate after event, or program a minimum time bet ween successive interrupts ? current rotary position is always available on demand for polling- based systems ? sounder output can be enabled to generate key-click sound when rotary is touched ? two hardware selectable i 2 c addresses allowing two devices on a single i 2 c bus ? configurable real-t ime auto calibration ? 5 mm x 5 mm x 1 mm 16 lead qfn package ? -40c to +85c operating temperature range implementations ? control panels ? switch replacements ? rotary and linear sliders typical applications ? appliances ? pc peripherals ? access controls ? mp3 players ? remote controls ? mobile phones ordering information device name temperature range case number rotary slider mpr083q -40 c to +85 c 1679 (16-lead qfn) 8-positions MPR083EJ 948f (16-lead tssop) e1 e2 e3 e4 e5 e6 e7 e8 vdd vss scl sda ad0 sounder attn irq mpr083 3 4 1 2 10 9 12 11 78 56 14 13 16 15 mpr083 capacitive touch sensor controller 16-lead tssop case 948f top view figure 1. pin connections bottom view 16-lead qfn case 1679 e1 e2 e3 e4 e5 e6 e7 e8 vdd vss scl sda ad0 sounder attn irq mpr083 1 4 3 2 5 8 7 6 16 13 14 15 12 9 10 11
mpr083 sensors 2 freescale semiconductor preliminary 1 device overview 1.1 introduction freescale semiconductor?s mpr083 proximity capacitive touch sensor controller is one of a family of products designed to detect the state of capacitive touch pads. the mpr 083 offers designers a cost-efficient alter native to mechanical rotary switches for control panel applications. the mpr083 uses an i 2 c interface to communicate with t he host which configures the operation and an interrupt to advise the host of status changes. the mpr083 includes a piezo sounder driv e which provides audible feedback to simulate mechanical key clicks. the mpr08x family has several implementations to use in your design including control panels and switch replacements. the mpr083 controls rotary and linear sliders. other members of the mpr08x family are well suited for other application interface situations such as individual touch pads or rotary/touch pad combinations. freescale offers a broad portfolio of proximity sensors for pr oducts ranging from appliance control panels to portable electron ics. target markets include consumer, appliance, industrial, medical and computer peripherals. 1.1.1 devices in the mpr08x series the mpr08x series of proximity capaci tive touch sensor controllers allows for a wide range of applications and implementations. each of the products in table 1 perform a different application specific task and are optimized for this specific functionality. 1.1.2 internal block diagram the mpr083 consists of primary functional blocks; interrupt controller, i 2 c serial interface, sounder controller, configuration and status registers, rotary position decoder, magnitude co mparator and recalibrator, emi burst/noise rejection filter, capacitance measurement analog front end. each of these bloc ks will be described in detail in their respective sections. figure 2. functional block diagram table 1. mpr08x family overview product bus sounder rotary/slider touch pad array mpr083 i 2 c yes 8-positions ? mpr084 i 2 c yes ? 8 keys configuration and status registers magnitude comparator and recalibrator emi burst/noise reject filter capacitance measurement a.f.e. 8 8 8 rotary position rotary position irq sda scl i 2 c serial interface interrupt controller masks set rate attn ad0 sounder sounder driver controller 8 position rotary 1 4 3 2 8 7 6 5 clear
mpr083 sensors freescale semiconductor 3 preliminary 1.1.3 terminology the following terms are used to describe front panel interface an d capacitive touch sensor technology throughout this document. table 2. terminology term definition touch sensor a touch sensor is the combination of a to uch sensor controller and a connected conductive area referred to as an electrode. touch sensor controller a touch sensor controller is the intell igent part of a touch sensor which measures capacitance and differentiates between touc hed and untouched pads. key a key or switch is a mechanical device that makes an electrical connection only when pressed. touch pad a touch pad is a type of capacitive sensor that is used for direct replacement of a key. a capacitive touch sensor determines touch state by differ entiating between high and low capacitances. when there is a change in the state this can be in terpreted in the same way as a mechanical key. encoder an encoder is a group of touch pads arranged in a circular shape where th e state of each touch pad is used to determine the directi on of rotation around the touch pads. rotary a rotary is a group of touch pads arranged in a circular shape where the state of each touch pad is interpreted as an angle along the touch pads. slider a slider is a group of touch pads arranged in a row where the state of each touch pad is used to determine the position along th e length of the touch pads. solid pad a solid or full pad is a type of touch pad where exactly one electrode is used split pad a split pad is a type of touch pad where more than one electrode is used. split pads are used to increase the total number of possib le touch pads without increasing th e electrical connections to the touch sensor controller. n-key lockout n-key lockout refers to the logic that determines how many keys can be simultaneously touched in a system. for example, 1-key lockout would only allow a single key to be touched before ignoring all future touches. n-key rollover n-key rollover refers to the logic that determines how many keys ca n be pressed in succession without releasing prev ious keys. for example, a system with 1-key lockout and 2-key rollover would allow 2-keys to be pressed in succession but would only report the second key once the first key was released. i 2 c inter-integrated circuit communication
mpr083 sensors 4 freescale semiconductor preliminary 2 external signal description 2.1 device pin assignment table 3 shows the pin assignment for the mpr083. for a more detailed description of the functionality of each pin, refer to the appropriate chapter. the two packages available for the mpr083 are a 5x5mm 16 pin qfn and a 4x5mm 16 pin tssop. both of the packages and their respective pinouts are shown in figure 3 . figure 3. package pinouts 2.2 recommended system connections the mpr083 capacitive touch sensor controller requires ten external passive components. when connecting the mpr083 in a touch sensor system, the electrode lines must have pull- up resistors. the recommended value for these pull-ups is 780k . some electrode arrays will require higher or lower values depending on the application. in addition to the 8 re sistors, a bypass capacitor of 1f should alwa ys be used between the vd d and vss lines and a 4.7 k pull-up resistor should be included on the irq . table 3. device pin assignment pin name function 1attn attention pin. input, active low when a sserted sets the confi guration register?s dce bit high allowing communication with the part. 2irq interrupt request pin. output, active-low, open -drain interrupt request signaling new events. 3 vdd positive supply voltage 4 vss ground 5scl i 2 c serial clock 6sda i 2 c serial data 7 ad0 address input. low = slave address 0x4c. high = slave address 0x4d. 8 sounder sounder driver output. connect a piezo sounder from this output to gr ound. output is push-pull 9 - 16 e1, e2, e3, e4, e5, e6, e7, e8 rotary electrode connections. pad exposed pad exposed pad on package undersi de (qfn only). connect to vss. e1 e2 e3 e4 e5 e6 e7 e8 vdd vss scl sda ad0 sounder attn irq 3 4 1 2 10 9 12 11 78 56 14 13 16 15 e1 e2 e3 e4 e5 e6 e7 e8 vdd vss scl sda ad0 sounder attn irq 1 4 3 2 5 8 7 6 16 13 14 15 12 9 10 11 qfn tssop
mpr083 sensors freescale semiconductor 5 preliminary the remaining 5 connections are scl, sda, irq , attn , and sounder. depending on the spec ific application, each of these control lines can be used by connecting them to a host syste m. in the most minimal system, the scl and sda must be connected to a master i 2 c interface to communicate with the mpr083. all of the connections fo r the mpr083 are shown by the schematic in figure 4 . figure 4. recommended system connections schematic note that in this configuration the ad0 address line is tied hi gh thus the slave address of the mpr083 0x4d. alternatively the address line can be pulled low if the host system needs the mpr083 to be on a ddress 0x4c. this functionality can also be used to incorporate tw o mpr083 devices in the same system. 2.3 serial interface the mpr083 uses an i 2 c serial interface. the i 2 c protocol implementation and the spec ifics of communicating with the touch sensor controller are detailed in the following sections. 2.3.1 serial-addressing the mpr083 operates as a slave that sends and receives data through an i 2 c 2-wire interface. the interface uses a serial data line (sda) and a serial clock line (scl) to achieve bi-directi onal communication between master(s) and slave(s). a master (typically a microcontroller) initiates all data transfers to and from the mpr083, and generates the scl clock that synchronize s the data transfer. the mpr083 sda line operates as both an input and an open-drain output. a pull-up resistor, typically 4.7k , is required on sda. the mpr083 scl line operates only as an input. a pull-up resistor, typically 4.7k , is required on scl if there are multiple masters on the 2-wire interface, or if the master in a single-master system has an open-drain scl output. each transmission consists of a start condition ( figure 5 ) sent by a master, followed by the mpr083?s 7-bit slave address plus r/w bit, a register address byte, one or more data bytes, and finally a stop condition. figure 5. wire serial interface timing details e1 e2 e3 e4 e5 e6 e7 e8 vdd vss scl sda ad0 sounder attn irq 1 4 3 2 5 8 7 6 16 13 14 15 12 9 10 11 780k 1 4 3 2 5 8 7 6 e1 e2 e3 e4 e5 e6 e7 e8 9 gnd gnd mpr083 scl sda sounder attn irq 8-position rotary electrode array 780k 780k 780k 780k 780k 780k 780k gnd 1 f v dd 4.7k v dd v dd scl sda t low t high t f t r t hd sta t hd dat t hd sta t su dat t su sta t buf t su sto start condit ion stop condit ion repeated start condit ion start condit ion
mpr083 sensors 6 freescale semiconductor preliminary 2.3.2 start and stop conditions both scl and sda remain high when the interface is not busy. a master signals the beginning of a transmission with a start (s) condition by transitioning sda from high to low while scl is high . when the master has finished communicating with the slave, it issues a stop (p) condition by transitioning sda from low to high while scl is high. the bus is then free for another transmission. figure 6. start and stop conditions 2.3.3 bit transfer one data bit is transferred during each clock pulse ( figure 7 ). the data on sda must remain stable while scl is high. figure 7. bit transfer 2.3.4 acknowledge the acknowledge bit is a clocked 9 th bit ( figure 8 ) which the recipient uses to handshake receipt of each byte of data. thus each byte transferred effectively requires 9 bits. the master generates the 9 th clock pulse, and the recipient pulls down sda during the acknowledge clock pulse, such that the sda line is stable low during the high period of the clock pulse. when the master is transmitting to the mpr083, the mpr083 generates the acknowledge bit because the mpr083 is the recipient. when the mpr083 is transmitting to the master, the master generates the acknowledge bit because the master is the recipient. figure 8. acknowledge data line stable data valid change of data allowed sda scl start condition sda scl stop condition p s start condition sda by transmitter s 12 89 clock pulse for acknowledgement sda by receiver scl
mpr083 sensors freescale semiconductor 7 preliminary 2.3.5 the slave address the mpr083 has a 7-bit long slave address ( figure 9 ). the bit following the 7-bit slave address (bit eight) is the r/w bit, which is low for a write command and high for a read command. figure 9. slave address the mpr083 monitors the bus continuously, waiting for a start condition followed by its slave address. when a mpr083 recognizes its slave address, it acknowledges a nd is then ready for continued communication. 2.3.6 message format for writing the mpr083 a write to the mpr083 comprises the transmission of the mpr083?s keyscan slave address with the r/w bit set to 0, followed by at least one byte of information. the first byte of information is the command byte. the command byte determines which register of the mpr083 is to be written by the next byte, if re ceived. if a stop condition is detected after the command byte i s received, then the mpr083 takes no further action ( figure 10 ) beyond storing the command byte. any bytes received after the command byte are data bytes. figure 10. command byte received any bytes received after the command byte are data bytes. the fi rst data byte goes into the inte rnal register of the mpr083 selected by the command byte ( figure 11 ). figure 11. command and single data byte received if multiple data bytes are transmitted before a stop condition is detected, these bytes are ge nerally stored in subsequent mpr083 internal registers because the command byte address generally auto-increments ( section 2.4 ). 2.3.7 message format for reading the mpr083 the mpr083 is read using the mpr083?s internally stored comm and byte as address pointer, the same way the stored command byte is used as address pointer for a write. the pointer genera lly auto-increments after each data byte is read using the same rules as for a write ( section 6.4.1 ). thus, a read is initiated by first configuring the mpr083?s command byte by performing a write ( figure 12 ). the master can now read ?n? consecut ive bytes from the mpr083, with the first data byte being read from the register addressed by the initialized command byte. sda 1 r/w ack msb scl 01 0100 saap 0 slave address command byte acknowledge from mpr083 r/w acknowledge from mpr083 d7 d6 d5 d4 d3 d2 d1 d0 commandbyteisstoredonreceiptofstopcondition sa aap 0 sl ave address command byt e data byt e acknowledge from mpr083 r/w 1byte auto-i ncrement memory word address d15 d14 d13 d12 d11 d10 d9 d8 d1 d0 d3 d2 d5 d4 d7 d6 how command byte and data byte map into mpr083's registers acknowledge from mpr083 acknowledge from mpr083
mpr083 sensors 8 freescale semiconductor preliminary when performing read-after-write verifica tion, remember to re-set the command by te?s address because the stored command byte address will generally have been auto-incremented after the write ( section 2.4 ). figure 12. ?n? data bytes received 2.3.8 operation with multiple master the application should use repeated starts to a ddress the mpr083 to avoid bus confusion between i 2 c masters.on a i 2 c bus, once a master issues a start/repeated start condition, that master owns the bus until a stop condition occu rs. if a master that does not own the bus attempts to take control of that bus, then improper addressing may occur. an address may always be rewritten to fix this problem. follow i 2 c protocol for multiple master configurations. 2.3.9 device reset the rst is an active-low software reset. this is implemente d in the configuration regi ster by activating the rst bit. when asserted, the device clears any transaction to or from the mpr083 on the serial interf ace and configures the internal registers to the same state as a power-up reset ( ta b l e 4 ). the mpr083 then waits for a start condition on the serial interface. the sensor controller is capable of operating down to 1.8 v, ho wever, in order for the sensor controller to exit reset and star tup correctly the host system must initiall y provide 2.0 v to 3.6 v input to v dd and then follow the process in figure 13 . this process is required in applications that require r egulated operation in the 1.8 v to 2.0 v ra nge. in the case that the application uses an unregulated battery, then the battery must initially provide at le ast 2.0 v to correctly power-up the sensor controller which l imits battery selection to the 2.0 v to 3.6 v range. figure 13. low voltage (1.8 v - 2.0 v) power-up sequence saaap 1 slave address command byte data byt e acknowledge from mpr083 r/w nbytes auto-i ncrement memory word address d15 d14 d13 d12 d11 d10 d9 d8 d1 d0 d3 d2 d5 d4 d7 d6 how command byte and data byte map into mpr083's registers acknowledge from mpr083 acknowledge from mpr083 established comms with sensor controller? i.e. read from fifo is data valid? (0 x 40) idle delay loop apply 2.0v to v dd max to sensor controller lower v dd to the desired operating voltage 1.8 v to 2.0 v false tr u e
mpr083 sensors freescale semiconductor 9 preliminary 2.4 register address map the mpr083 is a peripheral that is controlled and monitored though a small array of internal registers which are accessed through the i 2 c bus. when communicating with the mpr083 each of the registers in ta b l e 4 are used for specific tasks. the functionality of each specific register is detailed in the following sections. table 4. register address map register register address burst mode auto-increment address fifo register 0x00 0x00 fault register 0x01 0x02 rotary status register 0x02 0x00 rotary configuration register 0x03 0x04 sensitivity threshold register 0x04 0x05 master tick period register 0x05 0x06 touch acquisition sample period register 0x06 0x07 sounder configuration register 0x07 0x08 low power configuration register 0x08 0x09 stuck key timeout register 0x09 0x0a configuration register 0x0a 0x00 sensor information register 0x0b 0x0b
mpr083 sensors 10 freescale semiconductor preliminary 3 touch detection 3.1 introduction when using a capacitive touch s ensor system the raw data must be filtered and interpreted. th is process can be done many different ways but the method used in the mpr083 is explained in this chapter. 3.2 understanding the basics the rotary interface has to distinguish touch status through vary ing user conditions (different fi nger sizes in bare hands or g loves) and environmental conditions (electrical and rf noise, sensor contamination with dirt or moisture). the rotary circuitry reports touch status as one of the following two conditions: 1. rotary untouched 2. rotary touched in one of eight positions. the rotary is only touched in one position, ideally near the midd le of one of the eight pads. if a touch occurs between pads, untouched will be reported. 3.3 conditional output scenarios since it is unlikely that in a real world case a single in dependent touch will occur two specific multi-touch response cases ar e outlined. methods for changing the sensitiv ity of the device will be discussed in anothe r chapter, but the important part is th at the sensitivity is determined by the strength of an input signal. if more than one inpu t signal is above the selected sensitivity t hen the touch sensor controller interprets this in a specific way. this functionality is broken down into two different cases. 3.3.1 simultaneous touches any time two touches are detected at the same time the touch sensor controller recognizes this case and accounts for it. any time more than one key is pressed the t ouches are ignored. thus the t ouch sensor controller will show the rotary as untouched. in most cases one of the two electrodes will receive a stronger signal than the other. if the difference in capacitance is stat istically significant between the pad with the stronger signal will be reported. this functionality is some times called 1-key lockout. 3.3.2 sequential touches another case is when one rotary pad is touched and held and a se cond rotary pad is then touched and held. for this situation the second touch will be ignored and the first touch will continue to be reported. if the second touch is released before th e first touch then the second touch will be completely ignored. but, if the first touc h is released before the second then the system will report that the firs t key is released and that the second key is now touched. t his functionality is sometimes called 2-key rollover. 3.4 rotary configuration register the rotary configuration register configures a variety of the mpr083 features. each of these features is described in following sections. the i 2 c slave address of the rotary co nfiguration register is 0x03. figure 14. rotary configuration register 7 6 543210 r rse 00 ace rrbe rtbe 0 re w reset:1 0 000001 = unimplemented
mpr083 sensors freescale semiconductor 11 preliminary 3.5 touch acquisition sa mple period register the touch acquisition sample period register is used to determine the elec trode scan period of the system. the i 2 c slave address of the touch acquisition sample period register is 0x06. figure 15. touch acquisition sample period register table 5. rotary configuration register field descriptions field description 7 rse rotary sounder enable ? the rotary sounder enable bit controls if data is sent to the sounder. 0 disable ? click feedback off 1 enable ? click feedback on 4 ace auto calibration enable ? the auto calibration enable bit enables or disables the auto calibration function. 0 disable 1 enable 3 rrbe rotary release buffer enable ? the rotary release buffer enable bit determines whether or not data is logged in the fifo when the rotary transitions from a touched to untouched state. 0 disable ? no release data logged 1 enable ? release data logged 2 rtbe rotary touch buffer enable ? the rotary touch buffer enable bit determines whether or not data is logged in the fifo any time a button is pressed. 0 disable ? touches are not logged 1 enable ? touches are logged 0 re rotary enable ? the rotary enable bit enables or disables the touch sensor. when disabled, no touches are detected. 0 disable ? touches not detected 1 enable ? touches detected 7 6 543210 r tasp w reset:0 0 000001 = unimplemented table 6. touch acquisition sample register field description field description 7:0 tasp touch acquisition sample period ? the touch acquisition sample period field selects or reports the multiplication factor that is used to determine how often electrodes are scanned. the resulting factor must be in the range 1 to 32. if the value is outside of this range the tasp will be set to 00011111. 00000000 encoding 0 ? sets the t asp multiplication factor to 1 ~ 00011111 encoding 31 ? sets the tasp multiplication factor to 32.
mpr083 sensors 12 freescale semiconductor preliminary 4 modes of operation 4.1 introduction the operating modes of the mpr083 are described in this section. implementation and functionality of each mode are described. the modes of operation of the mpr083 combine to form a suite of quick resp onse and low power consumptio n functionality. this is achieved through 2 run modes and 2 stop modes. the two mo des are enabled by toggling the configuration register?s dce and rune bits as shown in ta b l e 7 . note that while in a run mode, the only register that can be written to is the configuration register. thus, when changes to registers are needed, enter stop1 mode, write to the registers and change the mode to ?run?. 4.2 initial power up on power-up, the interrupt output irq is reset, and irq will go high. the registers are reset to the values shown in table 8 . table 7. mode enable register bits mode rune dce run1 1 1 run2 1 0 stop1 0 1 stop2 0 0 table 8. power-up register configurations register function power-up cond ition register address hex value fifo register fifo is empty 0x00 0x40 fault register no faults 0x01 0x00 rotary status register rotary is untouched 0x02 0x00 rotary configuration register rotary is enabled, without interrupts, with sounder enabled and auto-cal disabled 0x03 0x81 sensitivity threshold register maximum sensitivity 0x04 0x00 master tick period register master clock period is 10ms 0x05 0x05 touch acquisition sample period register tasp is 1 master tick period 0x06 0x01 sounder configuration register sounder is globally enabled, 10ms of 1khz 0x07 0x01 low power configuration register low power mode is disabled 0x08 0x00 stuck key timeout register stuck key detector disabled 0x09 0x00 configuration register stop1 mode. irq is disabled 0x0a 0x14 sensor information register fixed sensorinfo based on revision 0x0b 0xff
mpr083 sensors freescale semiconductor 13 preliminary 4.3 run1 mode when in run1 mode the sensor controller wi ll run continuously. during run1 all the mo dules are synchronized by the master tick period. this value can be set by using the master tick period register as outlined in the following section. while in this mode all functionality of the mp r083 is enabled; touch detection will occur, and i 2 c communication will be available. this mode is enabled by setting the configuration register?s rune and dce bits high. 4.3.1 master tick period register the master tick period register is used to set the master tick of this system. all parts of the system are synchronized to this counter. this register is overridden in all modes except for ru n1. when not in run1 mode, the value of this register is ignored and 8ms is used for the primary clock. the i 2 c slave address of the master tick period register is 0x05. figure 16. master tick period register 4.4 run2 mode when in run2 mode the sensor controller will continue to sc an the electrodes but a low pow er state will be enabled between each cycle. because of this, any i 2 c communication that occurs, may or may not respond while the sensor is in this mode. if dce is enabled the sensor controller transit ions between low power and active states. during the active part of the cycle communication with the sensor controller is possible; however, freescale always requires users to issue an attn signal prior to initiating communicati ons. accessing the i 2 c interface while dce mode is enabled without sending an attn signal first is likely to produce invalid data. this mode is enabled by setting the configuration register?s rune bit high and dce bit low. the only way to exit this mode is to toggle the attention pin, refer to section 4.7 . 4.5 stop1 mode when in stop1 mode the sensor controller will not scan the electrodes. while capaci tance sensing is disabled i 2 c communications will still be accepted and the sensor controller wil l maintain instantaneous response to all register requests. this is the only mode in which register values can be set. this mode is enabled by setting the configuration register?s rune bit low and dce bit high. 4.6 stop2 mode when in stop2 mode the sensor controlle r will not scan the electrodes or accept i 2 c communication. the mpr083 is off during this mode. this mode is enabled by setting the co nfiguration register?s rune bit low and dce bit low. the only way to exit this mode is to toggle the attention pin, refer to section 4.7 . 7 6 543210 r mtp w reset:0 0 000101 = unimplemented table 9. master tick period register field descriptions field description 7:0 mtp master tick period ? the master tick period selects or reports the current value of the touch sensor controller?s primary clock multiplier. the resulting period must be in the range 5ms to 31ms. if the value is outside of this range the mtp will be set to 00011010. 00000000 encoding 0 ? sets the primary clock multiplier to 5 ~ 00011010 encoding 26 - sets the primary clock multiplier to 31
mpr083 sensors 14 freescale semiconductor preliminary 4.7 configuration register the configuration register allows a user to reset the part, adjust interr upt settings, and change the mode. the i 2 c slave address of the configuration register is 0x0a. figure 17. configuration register 4.8 attention pin the attention (attn ) pin allows a user to externally set the configuration register?s dce bit high. this is latched on a high to low transition. since the current mode of the device is enabled through the dce this will cause duty cycli ng to be disabled and change the current mode from run2 to run1, or st op2 to stop1 (depending on the previous state). when in run2 or stop2 modes this is the only way to enable the i 2 c communication. 7 6 543210 r rst 0 dce irqen rune w reset:0 0 010100 = unimplemented table 10. configuration register field descriptions field description 7:5 irqr interrupt rate ? the interrupt rate field selects the amount to multiply the mtp by to determine the minimum delay between sequential interrupts. 000 encoding 0 ? sets the irqr multiplication factor to 1 ~ 111 encoding 7 ? sets the irqr multiplication factor to 8 4 rst reset ? asserts a global reset of the sensor controller. 0 reset asserted 1 reset not asserted 2 dce duty cycle enable ? the duty cycle enable bit enables or disables duty cycling on the mpr083. this bit is active low. 0 duty cycle enabled (2 modes) 1 duty cycle disabled (1 modes) 1 irqen interrupt enable ? the interrupt enable bit enables or disables the irq functionality. 0 irq disabled 1 irq enabled 0 rune run mode enable ? the run mode enable bit enables or disables scanning of the electrodes for touch detection. this bit is active high. 0 electrode scanning disabled (stop modes) 1 electrode scanning enabled (run modes)
mpr083 sensors freescale semiconductor 15 preliminary 5 low power configuration 5.1 introduction the mpr083 features a low power mode that can reduce the powe r consumption into the microamps range. this feature can be used to both adjust the response time of the system, and change the conditions on which low power would be enabled. 5.2 operation this low power configuration is only active when the sensor controller is in run2 mode. the low power mode decreases current consumption by increasing the response time of the mp r083. this increase is cont rolled through two factors. during normal run2 operation of the sensor controller the max re sponse time (mrt) is calculated by taking the product of the tasp and the primary clock. from chapter 4 the primary clock is the (mtp + 5) ms. sinc e the sensor controller is in run2, the primary clock is also multiplied by a factor of 8. the debounce ra te of the mpr083 is 4 times the sample rate thus the mrt is represented by the following equation. equation 1 first, the idle interface timeout (iit) represents the total time the touch inte rface should remain idle before going into low power mode. this value can be calculated by taking the product of the it p, tasp and primary clock (8ms) with a factor of 64. thus the iit is represented as follows: equation 2 second, the max response time (mrt) represents the total time the touch interface should remain inactive before scanning the electrodes. this value can be calculated by taking the product of the scd, tasp and primary clock (8ms) with a factor of 5. thu s the mrt is represented as follows: equation 3 when in run2 mode, the sensor controller will init ially scan the electrodes at the rate of mrt 1 . when scanning at mrt 1 and the touch interface remains idle for the iit period then the scan period will change to mrt 2 . when scanning at mrt 2 and a touch is detected the scan rate will transition back to mrt 1 . figure 18. low power scan period transition diagram mrt 1 mtp 5 + 8 ------------ --------- - 1 + ?? ?? tasp 48 ms = mrt 2 mtp 5 + 8 ------------ --------- - 1 + ?? ?? tasp scd 48 ms = itt mtp 5 + 8 ----------- ---------- - 1 + ?? ?? tasp itp 68 ms = lp disabled itt period run2 set touch detected mrt 1 mrt 2
mpr083 sensors 16 freescale semiconductor preliminary 5.3 configuration low power configuration is achieved through setting two values ; the idle timeout period and the sleep cycle duration. this functionality is described in the following section. 5.3.1 low power configuration register the low power configuration register is used to set both the id le timeout period and sleep cycle duration multiplication factor s. the i 2 c slave address of the low power configuration register is 0x08. figure 19. low power configuration register 7 6 543210 r itp scd w reset:0 0 000000 = unimplemented table 11. low power configuration register field descriptions field description 7:5 itp idle timeout period ? the idle timeout period selects the amount to multiply the tasp (touch acquisition sample period) by to determine the idle interface timeout (iit) period of the sensor controller. 000 encoding 0 ? disables low power mode 001 encoding 1 ? sets the itp multiplication factor to 1 ~ 111 encoding 7 ? sets the itp multiplication factor to 7 4:0 scd sleep cycle duration ? the sleep cycle duration field selects the amount to multiply the tasp (touch acquisition sample period) by to determine the sleep period of the sensor controller. 00000 encoding 0 ? disables low power mode 00001 encoding 1 ? sets the scd multiplication factor to 1 ~ 11111 encoding 31 ? sets the scd multiplication factor to 31
mpr083 sensors freescale semiconductor 17 preliminary 6 output mechanisms 6.1 introduction the mpr083 has three primary methods for reporting data in addition to an irq output that is described in chapter 7. the three output systems are descri bed in this section. 6.2 instantaneous the instantaneous output shows the current st atus of the user interface. this informa tion is displayed in terms of the current rotary position that is touched. only one touch can be shown at a time. 6.2.1 rotary status register the rotary status register is a read only register for determining the current status of the rotary. the i 2 c slave address of the rotary status register is 0x02. figure 20. rotary status register 6.3 buffered the buffered output is done through a fifo . the fifo will buffer every t ouch that occurs up to 30 values before the buffer overflows and data is lost. any time data is read from the fifo it is pulled from the buffer and the next item becomes availabl e. the buffer can be cleared (ndf goes high) by either readi ng the last entry or attempti ng to write to the register. the buffer settings are configured in the rota ry configuration register as described in section 3.4 . 6.3.1 fifo register the fifo register is a read only register for determining the curr ent status of the rotary. any time a write is issued to this register the buffer will be cleared. the i 2 c slave address of the fifo register is 0x00. figure 21. fifo register 7 6 543210 r0 0 0 sf cp w reset:0 0 000000 = unimplemented table 12. rotary status register field descriptions field description 4 sf status flag ? the status flag shows when t he rotary is currently detecting a touch. 0 rotary is not currently detecting a touch 1 rotary is currently detecting a touch 3:0 cp current position ? the current position represents the electrode that is currently being touched. 0000 encoding 0 ? electrode 1 is currently touched ~ 0111 encoding 7 ? electrode 8 is currently touched 7 6 543210 r mdf ndf of trf bp w reset:0 1 000000 = unimplemented
mpr083 sensors 18 freescale semiconductor preliminary 6.4 error the mpr083 can generate a fault under two conditions; an electrode is shor ted to vdd, or an electrode is shorted to vss. once a fault is asserted the sensor electrodes will no longer be scann ed until the fault is cleared. in the event of multiple faults occurring at the same time, the se nsor controller will report the first faul t that is detected during scanning. 6.4.1 fault register the fault register is a read only register that shows the faul t number under the current sensor conditions. any write to the fa ult register will clear the register, when in stop mode. the fault r egister cannot be cleared when the part is in a run mode. the i 2 c slave address of the fault register is 0x01. figure 22. fault register table 13. fifo register field descriptions field description 7 mdf more data flag ? the more data flag shows whether or not data will remain in the buffer after the current read. 0 no data remaining 1 data remaining 6 ndf no data flag ? the no data flag shows whether or not there is currently data in the buffer. 0 buffer currently has data 1 buffer does not currently have data 5 of overflow flag ? the overflow flag shows whether or not an overflow has occurred. if this flag is high then the most current data was lost. 0 no overflow has occurred 1 overflow has occurred 4 trf touch release flag ? the touch release flag shows if the current buffer entry is a touch or release of a pad. 0 pad is released 1 pad is touched 3:0 bp buffered position ? the buffered position represents the electr ode number that is currently being displayed by the buffer. 0000 encoding 0 ? buffered touch of electrode 1 ~ 0111 encoding 7 ? buffered touch of electrode 8 7 6 543210 r0 0 0 0 0 0 fault w reset:0 0 000000 = unimplemented table 14. fault register field descriptions field description 1:0 fault fault ? the fault code represents t he currently asserted fault condition. 00 encoding 0 ? no fault detected 01 encoding 1 ? short to vss detected 10 encoding 2 ? short to vdd detected
mpr083 sensors freescale semiconductor 19 preliminary 7 interrupts 7.1 introduction the mpr083 has one interrupt output that is configured by registers and alerts the ap plication when a touch or fault is detecte d. when running in run2 or stop2 mode where i 2 c communication is not available this feature alerts the user to sensor touches. 7.2 condition for interrupt there are two cases that latch the interrupt buffered data available or fault detected. 7.2.1 buffered data available the interrupt for buffered data available will only trigger when the ndf (no data flag) transitions from high to low. this sign ifies that there is new data available in the buffer. the interrupt is deasserted on the first read/writ e of the fifo register and ca nnot be reasserted for buffered data until the fifo is empty (e ither by reading all the data, or clearing the buffer). 7.2.2 fault detected the interrupt for a fault detected condition is triggered any time the fault condition in the fault register transitions from z ero to non-zero. the interrupt is deasserted when the fault re gister is cleared (by writing to the fault register). 7.3 settings interrupts are configured through i 2 c using the configuration register ( section 4.7 ). two of the settings in this register will affect the interrupt functionality. the interrupt enable (irqen) must be set high for the irq to be enabled. when low, all interrupts will be ignored, and the irq pin will never latch. the interrupt rate (irqr) sets the minimum delay between seque ntial triggered interrupts. the minimum interrupt period can be calculated by taking the product of the (mtp + 5) and irqr wit h a factor of 4. thus, for the minimum setting an interrupt would be triggered no more often than 4 times the master clock. equation 4 if the mpr083 is using run2, the minimum interrupt period would be represented by the following equation. equation 5 7.4 irq pin the irq pin is an open-drain, latching interrupt output which require s an external pull-up resistor. the pin will latch down based on the conditions in section 6.2 . the pin will reset when an i 2 c transmission reads/writes the appropriate register displaying information about the source of the interrupt. thus if the sour ce is buffered data available then a fifo buffer read/write will clear the irq pin. if the source is a faul t detected then a write of the f ault register will clear the pin. mininterruptperiod ms () mtp 5 + () irqr 4 = mininterruptperiod ms () mtp 5 + 8 --------------------- - 1 + ?? ?? 8 i rqr 4 =
mpr083 sensors 20 freescale semiconductor preliminary 7.4.1 irq pin timing the mininterruptperiod is im plemented as a hold off of irq latching per figure 23 and figure 24 . in the first case the mininterruptperiod is longer than the interval between sequential interrupt source events, thus it delays the irq from latching until the mininterrupt period has elapsed. figure 23. irq timing diagram - case 1 in the second case the mininterruptperiod is shorter than the interval between sequent ial interrupt source events, thus the irq latches as it normally would without additional delay. figure 24. irq timing diagram - case 2 initial interrupt event mininterruptperiod second interrupt event irq initial interrupt event mininterruptperiod second interrupt event irq
mpr083 sensors freescale semiconductor 21 preliminary 8calibration 8.1 introduction the mpr083 is self-calibrating. this is done both at initial start-up of the device and during run time. 8.2 initial start-up conditions initial calibration of the mpr083 occurs every time the device resets. the fi rst key detection cycle is used as a baseline capacitance value for all remaining calculations. thus, a touch is detected by taking the differ ence between this baseline valu e and the current capacitance on the electrode. 8.3 auto-calibration the mpr083 has an auto-calibration feat ure. this is enabled through the rotary configuration register ( section 3.4 ), by setting the ace bit high. auto calibration is done by two mechanisms. the basic auto-calibration will recalculate the baseline value af ter 6 sample periods. thus the auto calibrate period can be calculate by multiplying the master clock period (in milliseconds) and the touch acquisition sample period with a factor of 64. equation 6 if a touch is currently being detected the auto-calibration will not engage and calibration will be ignored. the device can als o be calibrated when a key is being touched, th is is controlled by stuck key detection. 8.4 stuck key detection the stuck key detection system allows the application to specif y the maximum amount of time a touch should be detected before it is calibrated into the baseline and the touch is ignored. this is controlled by setting the stuck key timeout multiplication factor (skt). the timeout period can be calculated by multiplying the skt, master clock period (in ms) and touch acquisition sample period with a factor of 64. equation 7 when stuck key detection is off a touched key will remain touc hed indefinitely and never be calibrated into the baseline value. 8.4.1 stuck key timeout register the stuck key timeout register is used to dete rmine the electrode scan per iod of the system. the i 2 c slave address of the stuck key timeout register is 0x09. figure 25. stuck key timeout register 7 6 543210 r skt w reset:0 0 000000 = unimplemented table 15. stuck key timeout register field descriptions field description 7:0 skt stuck key timeout ? the stuck key timeout field selects or reports the multiplication factor that is used to de termine how often electrodes are calibrated while a touch is being detected. 00000000 encoding 0 ? turns off stuck key detection 00000001 encoding 1 ? sets the skt multiplication factor to 2 ~ 11111111 encoding 255 ? sets the skt multiplication factor to 256 autocalibrationperiod ms () mcp tasp 64 = autocalibrationperiod ms () mcptaspskt 64 =
mpr083 sensors 22 freescale semiconductor preliminary 9 sensitivity 9.1 introduction the mpr083 can operate in a variety of envir onments with a variety of different electro de patterns. because of this it is neces sary to adjust the relative sensitivity of th e sensor controller. usually this requires fine tuning in any final application. there are many factors that must be taken into account, but much of the time th is value is relative to the capacitance changes generated by a touch. since capacitance is di rectly proportional to the di electric constant of the material and the area of the pad, while inversely proportional to the distance between pads these are the primary factors. equation 8 as the relative capacitance rises the sens itivity setting of the mpr083 should be adjusted accordingly. thus a very high sensit ivity value represents a large a and a small d. 9.2 adjusting the sensitivity the sensitivity of the mpr083 is adjusted by varying the s ensitivity threshold register. 9.2.1 sensitivity threshold register the sensitivity register allows t he sensitivity of the mpr083 to be adjusted for any situation. the i 2 c slave address of the sensitivity threshold register is 0x04. figure 26. sensitivity threshold register 7 6 543210 r sl w reset:0 0 000000 = unimplemented table 16. sensitivity threshol d register field descriptions field description 7:0 st sensitivity threshold ? the s ensitivity threshold selects or reports the sensitivity setting of the sensor contro ller. the resulting value must be in the range 1 to 64 units. if the value is outside of this range the st will be set to 00111111. 00000000 encoding 0 ? sets t he sensitivity to level 1 ~ 00111111 encoding 63 ? sets the sensitivity to level 64 c ke 0 a d ----------- - =
mpr083 sensors freescale semiconductor 23 preliminary 10 additional features 10.1 key click sound generator the key click sound generator allows the mpr083 to generate audible feedback, independent of the i 2 c communication status. the sounder is used to drive a piezo buzzer. this output is conf igured by using the sounder register, shown in the following section. 10.1.1 sounder configuration register the i 2 c slave address of the sounder configuration register is 0x07. figure 27. sounder configuration register 10.2 sensor information the sensor information register is a read only register that displays a descriptor which contains static information about the mpr083 version. 10.2.1 sensor information register the i 2 c slave address of the sensor information register is 0x0b. figure 28. sensor information register 7 6 543210 r0 0 000 cp freq sen w reset:0 0 000001 = unimplemented table 17. sounder configuration register field descriptions field description 2 cp click period ? the click period bit controls the length of the sounder click. 0 sounder click period is 10ms 1 sounder click period is 20ms 1 freq frequency ? the frequency bit controls the frequency of the driven output. 0 sounder frequency is 1khz 1 sounder frequency is 2khz 0 sen sounder enable ? the sounder enable bit enables or disables the sounder output. 0 disable 1 enable 7 6 543210 r sensorinfo w reset:0 1 000110 = unimplemented table 18. sensor information register field descriptions field description 7-0 sensorinfo sensorinfo ? the sensor information register describes the version information for the part. burst reads will display ascii data in the following format: vendor_label",pn:"product_label", qual:"build_type_label",ver:" build_version_major"_"build_ver sion_minor"_"build_number"\0"
mpr083 sensors 24 freescale semiconductor preliminary appendix a electrical characteristics a.1 introduction this section contains electric al and timing specifications. a.2 absolute maximum ratings absolute maximum ratings are stress ratings only, and functional ope ration at the maxima is not guaranteed. stress beyond the limits specified in table a-1 may affect device reliability or cause permanent damage to the dev ice. for functional operating conditions, refer to the remaining tables in this section. this device contains circuitry protecting against damage due to high static voltage or electrical fields; however, it is advised that norma l precautions be taken to avoid application of any voltages high er than maximum-rated voltages to this high-impedance circuit. a.3 esd and latch-up prot ection characteristics normal handling precautions should be used to avoid exposure to static discharge. qualification tests are performed to ensure that these devices can withstand exposur e to reasonable levels of static without suffering any permanent damage. during the device qualificatio n esd stresses were performed for the human body model (hbm), the machine model (mm) and the charge device model (cdm). a device is defined as a failure if after exposure to esd pulse s the device no longer meets the device specification. complete dc parametric and functional testing is performed per the applicab le device specification at room temperature followed by hot temperature, unless specified other wise in the device specification. table 19. absolute maxi mum ratings - voltage (with respect to vss) rating symbol value unit supply voltage v dd -0.3 to +3.8 v input voltage scl, sda, ad0, irq , attn , sounder v in vss - 0.3 to vdd + 0.3 v operating temperature range tsg -40 to +85 c storage temperature range t sg -55 to +150 c table 20. esd and latch-up test conditions rating symbol value unit human body model (hbm) v esd 2000 v machine model (mm) v esd 200 v charge device model (cdm) v esd 500 v latch-up current at t a = 85c i latch 100 ma
mpr083 sensors freescale semiconductor 25 preliminary a.4 dc characteristics this section includes information about power supply requirements and i/o pin characteristics. *the mpr083 requires a specific start-up sequence for v dd < 2.0 v. refer to section 2.3.9 . a.5 i 2 c ac characteristics this section includes information about i 2 c ac characteristics. table 21. dc characteristics (temperature range = ?40c to 85c ambient) (typical operating circuit, v dd = 1.8 v* to 3.6 v, t a = t min to t max , unless otherwise noted. typical current values are at v dd = 3.3 v, t a = +25c.) parameter symbol conditions min typ max units operating supply voltage v dd 1.8* 3.6 v run1 mode current i run1 v dd = 1.8 v 1.62 ma run2 mode current i run2 v dd = 1.8 v 41 a stop1 mode current i stop1 v dd = 1.8 v 1.47 ma stop2 mode current i stop2 v dd = 1.8 v 2 a input high voltage sda, scl v ih 0.7 x vdd v input low voltage sda, scl v il 0.35 x vdd v input leakage current sda, scl i ih , i il 0.025 1 a input capacitance sda, scl 7pf output low voltage sda, irq v ol i ol = 6ma 0.5v v table 22. i 2 c ac characteristics (typical operating circuit, v dd = 1.8 v to 3.6 v, t a = t min to t max , unless otherwise noted. typical values are at v dd = 3.3 v, t a = +25c.) parameter symbol conditions min typ max units serial clock frequency (1) 1. clock stretching is required for reliable communications f scl 100 khz capacitive load for each bus line c b 400 pf
mpr083 sensors 26 freescale semiconductor preliminary appendix b brief register descriptions fifo register: 0x00 fault register: 0x01 rotary status register: 0x02 rotary configuration register: 0x03 sensitivity threshold register: 0x04 master tick period register: 0x05 7 6 543210 r mdf ndf of trf bp w reset:0 1 000000 = unimplemented 7 6 543210 r0 0 0 0 0 0 fault w reset:0 0 000000 = unimplemented 7 6 543210 r0 0 0 sf cp w reset:0 0 000000 = unimplemented 7 6 543210 r rse 00 ace rrbe rtbe 0 re w reset:1 0 000001 = unimplemented 7 6 543210 r sl w reset:0 0 000000 = unimplemented 7 6 543210 r mtp w reset:0 0 000101 = unimplemented
mpr083 sensors freescale semiconductor 27 preliminary touch acquisition sample period register: 0x06 sounder configuration register: 0x07 low power configuration register: 0x08 stuck key timeout register: 0x09 configuration register: 0x0a sensor information register: 0x0b 7 6 543210 r tasp w reset:0 0 000001 = unimplemented 7 6 543210 r0 0 000 cp freq sen w reset:0 0 000001 = unimplemented 7 6 543210 r itp scd w reset:0 0 000000 = unimplemented 7 6 543210 r skt w reset:0 0 000000 = unimplemented 7 6 543210 r rst 0 dce irqen rune w reset:0 0 010100 = unimplemented 7 6 543210 r sensorinfo w reset:0 0 000001 = unimplemented
mpr083 sensors 28 freescale semiconductor preliminary appendix c order ing information c.1 ordering information this section contains ordering inform ation for mpr083q and MPR083EJ devices. c.2 device numbering scheme all proximity sensor products have a si milar numbering scheme. the below diagram ex plains what each part number in the family represents. ordering information device name temperature range case number rotary slider mpr083q -40 c to +85 c 1679 (16-lead qfn) 8-positions MPR083EJ 948f (16-lead tssop) m status (m = fully qualified, p = preproduction) pr proximity sensor product ee x p number of electrodes (08 = 8 electrode device) package designator version (q = qfn, ej = tssop)
mpr083 sensors freescale semiconductor 29 preliminary package dimensions page 1 of 3
mpr083 sensors 30 freescale semiconductor preliminary package dimensions page 2 of 3
mpr083 sensors freescale semiconductor 31 preliminary package dimensions page 3 of 3
mpr083 sensors 32 freescale semiconductor preliminary package dimensions page 1 of 3
mpr083 sensors freescale semiconductor 33 preliminary package dimensions page 2 of 3
mpr083 sensors 34 freescale semiconductor preliminary package dimensions package dimensions page 3 of 3
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