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10-point capacitive touch controller GT928 1 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. GT928 10-point capacitive touch controller for large-screen mobile phones rev.08 nov. 14, 2014 ====== disclaimer ====== the information concerning the device in this publication is intended for you only and is subject to change without prior notice. it is your responsibility to ensure its application complies with technical specifications. shenzhen huiding technology co., ltd. (hereafter referred to as ?goodix?) makes no representation or guarantee for this information, either expressed or implied, written or verbal, statutory or otherwise including but not limited to representation or guarantee for its application, quality, performance, merchantability or fitness for a particular purpose. goodix shall assume no responsibility for this information and relevant consequences arising out of the use of such information. without written consent of goodix, it is prohibited to use goodix products as critical components in any life support system. this document conveys no licenses, implicitly or otherwise, to any intellectual property rights belonging to goodix. _linu(
10-point capacitive touch controller GT928 2 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. contents 1. overview ............................................................................................................................... ....................... 5 2. features ............................................................................................................................... ........................ 5 3. block diagram ............................................................................................................................... .............. 6 4. pin configurations ............................................................................................................................... ....... 7 5. sensor design ............................................................................................................................... ............. 8 5.1 layout of rx channels .................................................................................................................. 8 5.2 layout of tx channels ................................................................................................................... 8 5.3 sensor design specifications ....................................................................................................... 9 5.4 touch key design ........................................................................................................................... 9 6. i 2 c communication ............................................................................................................................... ... 10 6.1 i 2 c timing ............................................................................................................................... ....... 10 a) data transmission .................................................................................................................... 12 b) writing data to GT928 ............................................................................................................. 12 c) reading data from GT928 ...................................................................................................... 13 7. hotknot mode ............................................................................................................................... ............ 14 7.1 start hotknot ................................................................................................................................ 14 7.2 data transmission between tps ............................................................................................... 14 7.3 host receives data from GT928 ............................................................................................... 14 8. description on functions ......................................................................................................................... 15 8.1 operating modes .......................................................................................................................... 15 a) normal mode ............................................................................................................................. 15 b) green mode ............................................................................................................................... 16 c) gesture mode ........................................................................................................................... 16 _linu(
10-point capacitive touch controller GT928 3 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. d) sleep mode ............................................................................................................................... 16 e) approach mode ......................................................................................................................... 16 f) receive mode ........................................................................................................................... 17 g) send mode ............................................................................................................................... .17 8.2 interrupt triggering mechanism .................................................................................................. 17 8.3 sleep mode ............................................................................................................................... .... 17 8.4 stationary configuration .............................................................................................................. 17 8.5 self-calibration ............................................................................................................................. 18 a) self-calibration during initialization ........................................................................................ 18 b) automatic drift compensation ................................................................................................ 18 8.6 finger touch and stylus touch transition ................................................................................ 18 a) finger touch .............................................................................................................................. 18 b) stylus touch ............................................................................................................................... 18 9. sample schematic ............................................................................................................................... .... 19 10. electrical characteristics ................................................................................................................. 20 10.1 absolute maximum ratings ........................................................................................................ 20 10.2 recommended operating conditions ....................................................................................... 20 10.3 ac electrical characteristics ...................................................................................................... 20 10.4 dc electrical characteristics ...................................................................................................... 21 11. package ............................................................................................................................... .............. 22 12. revision history ............................................................................................................................... .23 13. contact information .......................................................................................................................... 24 _linu(
10-point capacitive touch controller GT928 4 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 1.overview GT928, a new-generation 10-point capacitive touch sol ution designed for 7? to 10.1? portable devices, consists of up to 32 transmitter electrodes and 24 receiver electrodes to achieve higher accuracy and resolution. GT928 supports up to 10 concurrent touches with real -time tracking of accurate position and motion trajectory as well as touch area. furthermore, i t is able to report such information to the host as required. 2.features ? built-in capacitive sensing cir cuit and high-performance mpu ? report rate: 100hz ? outputs touch coordinates in real time ? unified software applicable to capacit ive touch screens of various sizes ? single power supply, internal 1.8v ldo ? flash embedded; in-system reprogrammable ? hotknot integrated ? capacitive touch screen sensor ? channels: 32(tx channels)*24(rx channels) ? supports capacitive touch screen sizes: 7? to 10.1? (diagonal) ? supports touch key design on fpc ? supports ito glass and ito film ? cover lens thickness supported: 0.7mm 0 glass 0 2mm 0.5mm 0 acrylic 0 1.2mm ? adaptive frequency hopping ? supports ogs full lamination ? hotknot ? transmission rate ? 7.0kbps (max) ? data frame maximum capacity ? 128 bytes ? applicable sensor types: ogs/conventional, gff/gg/ gf ? environmental adaptability ? self-calibration during initialization ? automatic drift compensation ? operating temperature: -40 to +85 ; humidity: 095%rh ? storage temperature: -60 to +125 ; humidity: 095%rh ? host interface ? standard i 2 c interface _linu(
10-point capacitive touch controller GT928 5 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. ? works in slave mode ? supports 1.8v to 3.3v host interface voltage ? response time ? green mode: <48ms ? sleep mode: <200ms ? initialization: <200ms ? power supply voltage: ? single supply: 2.8v to 3.3v ? power supply ripple: ? vpp 050mv ? package: 68 pins, 8mm*8mm qfn_0.4p ? tools provided to support application development: ? tp module parameter detector and generator ? integrated tool for tp module performance test ? tool for quality inspection during module mass-production ? reference driver code and documentary guide for host software development 3.block diagram _linu(
10-point capacitive touch controller GT928 6 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 4.pin configurations pin no. name function description remarks 1~17 sens7~sens23 receiver electrodes output drive signal while hotknot function is on 18 avdd28 analog power 2.2uf filter capacitor to gnd 19 avdd18 2.2uf filter capacitor to gnd 20 dvdd12 2.2uf filter capacitor to gnd 21 dgnd digital signal ground 22 int interrupt signal 23 sensor_opt1 module id pin 24 sensor_opt2 module id pin external pull-down resistor required 25 i2c_sda i 2 c data signal 26 i2c_scl i 2 c clock signal 27 vddio supply voltage of gpio 2.2uf filter capacitor to gnd floating: 1.8v connect to avdd: avdd 28 rstb reset pin external 10k pull-up resistor required, active-low reset 29~60 drv31~drv0 transmitter electrodes 61 agnd analog signal ground 62~68 sen0~sen6 receiver electrodes output drive signal while hotknot function is on _linu(
10-point capacitive touch controller GT928 7 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 5.sensor design 5.1 layout of rx channels sens0 to sens23 are 24 rx channels on the chip directly connected to 24 ito rx channels on the sensor either in sequence or re verse sequence. please refer to GT928 series channel selector for channel selection when there are less ito rx c hannels on the sensor than rx channels on the chip. sample layout: the ito rx channels on the sensor are connected to the rx channels on the chip in sequence from sens0 to sens23: 5.2 layout of tx channels drv0 to drv31 are 32 tx channels on the chip di rectly connected to 32 ito tx channels on the sensor. please refer to gt9 series channel selector for drv line channel selection and assignment. after the layout of the tx channels is determined, re levant registers of GT928 shall be configured to ensure logic positions of tx channels are consistent with their physica l positions, so that the reported coordinates match the physical coordinates. for details of sensor design, pl ease refer to layout guidelines. _linu(
10-point capacitive touch controller GT928 8 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 5.3 sensor design specifications GT928 dito sito tx routing trace impedance Q3k ? Q3k ? tx channel impedance Q10k ? Q10k ? rx routing trace impedance Q10k ? Q10k ? rx channel impedance Q40k ? Q10k ? node capacitance Q4pf Q4pf to ensure data consistency and uniformity on the entire screen, it i s necessary to ensure the sensor design complies with the above requirements. fo r detailed requirements, please refer to sensor design guidelines of goodix. in addition, when tx channel/trace and rx channel /trace are adjacent and parallel to each other, separate the channels/traces with a ground tra ce. for ground trace width, please refer to sensor design guidelines. note that ground trace width should be no less than 0.2mm. 5.4 touch key design GT928 supports at most 4 separated touch keys in the following two ways: 1) touch key design on sensor : take one tx channel as a common port for the touch keys and connect the tx channel to four rx channels to enable four touch keys. the touch keys must not share their tx channel with the touch screen. however, rx channels have to be shared. 2) touch key design on fpc: connect one separate tx channel to four rx channels to enable four touch keys. the touch keys have to share their rx channels with the touch screen. touch key pattern on fpc should be designed independently. _linu(
10-point capacitive touch controller GT928 9 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 6.i 2 c communication 6.1 i 2 ctiming GT928 provides a standard i2c interface for scl and sda to communicate with the host. GT928 always serves as slave device in the system with all communication being initialized by the host. it is strongly recommended that transmission rate be kept at or below 400kbps. the i 2 ctimingis shown below: sda scl t f t hd1 t f t lo t r t hi t hd2 t r t r t st2 t st1 t st3 t r t buf test condition 1: 1.8v host interface voltage, 400kbps transmission rate, 2k pull-up resistor parameter symbol min. max. unit scl low period t lo 1.3 - us scl high period t hi 0.6 - us scl setup time for start condition t st1 0.6 - us scl setup time for stop condition t st3 0.6 - us scl hold time for start condition t hd1 0.6 - us sda setup time t st2 0.1 - us sda hold time t hd2 0-us test condition 2: 3.3v host interface voltage, 400kbps transmission rate, 2k pull-up resistor parameter symbol min. max. unit scl low period t lo 1.3 - us scl high period t hi 0.6 - us scl setup time for start condition t st1 0.6 - us scl setup time for stop condition t st3 0.6 - us scl hold time for start condition t hd1 0.6 - us sda setup time t st2 0.1 - us sda hold time t hd2 0- us GT928 supports two i 2 c slave addresses: 0xba/0xbb and 0x28/0x29. the host can select the address by changing the status of reset and int pins during the power-on initialization phase. see the diagram below for detailed timings: _linu(
10-point capacitive touch controller GT928 10 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. power-on timing: timing for host resetting GT928: timing for setting slave address to 0x28/0x29: _linu(
10-point capacitive touch controller GT928 11 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. timing for setting slave address to 0xba/0xbb: a) data transmission (for example slave address is 0xba/0xbb) communication is always initiated by the host. va lid start condition is signaled by pulling sda line from high to low when scl line is high. data flow or address is transmitted after the start condition. all slave devices connected to i 2 c bus should detect the 8-bit addres s issued after start condition and send the correct ack. after receiving matching address, GT928 acknowledges by configuring sda line as output port and pulling sda line low during the ninth scl cycle. when receiving unmatched address, namely, not 0xba or 0xbb, GT928 will stay in an idle state. for data bytes on sda, each of 9 serial bits will be sent on nine scl cycles. each data byte consists of 8 valid data bits and one ack or nack bit sent by the recipient. the data transmission is valid when scl line is high. when communication is completed, the host will issu e the stop condition which implies the transition of sda line from low to high when scl line is high. b) writing data to GT928 (for example slave address is 0xba/0xbb) timing for write operation the diagram above displays the timing sequence of th e host writing data onto GT928. first, the host issues a start condition. then, the host sends 0xba ( address bits and r/w bit; r/w bit as 0 indicates write operation) to the slave device. after receiving ack, the host sends the 16-bit register address (where writing starts) and the 8-bit data bytes (to be written onto the register). the location of the register address pointer will automatically add 1 after every write operation. therefore, when the host needs to perform writ e operations on a group of registers of continuous addresses, it is able to write continuously. the writ e operation is terminated when the host issues the stop condition. _linu(
10-point capacitive touch controller GT928 12 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. c) reading data from GT928 (for example slave address is 0xba/0xbb) timing for read operation the diagram above is the timing sequence of the hos t reading data from GT928. first, the host issues a start condition and sends 0xba (address bits and r/w bit; r/w bit as 0 indicates write operation) to the slave device. after receiving ack, the host sends the 16-bit register address (where reading starts) to the slave device. then the host sets register addresses which need to be read. also after receiving ack, the host issues the s tart condition once again and sends 0xbb (read operation). after receiving ack, the host starts to read data. GT928 also supports continuous read operation and, by default, reads data continuously. whenever receiving a byte of data, the host sends an ack signal i ndicating successful rec eption. after receiving the last byte of data, the host sends a nack signal followed by a stop condition which terminates communication. _linu(
10-point capacitive touch controller GT928 13 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 7.hotknot mode 7.1 start hotknot when data needs to be sent, the host sends co mmand 0x21 to GT928, enabling GT928 to enter " master approach mode" and work as a transmittin g terminal. GT928 will then be able to detect the receiving terminal communicating with it. when GT928 succeeds in detecting the receiving terminal, it will notify the the host to shut off lcd using a n interrupt signal and then transmit data to the receiveing terminal. 7.2 data transmission between tps after GT928 and another hotknot terminal successfully detect one another, the host sends the hotknot transmission firmware to both terminals. while the transmission firmware runs, the two terminals are ready for data transmission, entering receive mode by default. when the GT928 transmit buffer is flushed correctly, GT928 works as the transmitting terminal and immediately transmits data to the other hotknot terminal, which works as a receiving terminal detecting data sent by GT928. 7.3 host receives data from GT928 following recieval or transmission of a data frame , GT928 inverts int to notify the host to process data. after receiving a data frame, the the host reads the va lue of the hotknot status register. if the value of the receive-status register indicates a successf ul reception, the host will read the data from the receive buffer via 12c. after reading the recieved data, the host writes 0xaa to the designated address and notifies GT928 t hat data reading is complete. after GT928 transmits a data frame, the host reads th e value of the hotknot status register. if the value of the transmit-status register indicates a successful transmission, the host will read the data from the transmit buffer via i 2 c. after reading this data, the host writes 0xaa to the designated address and notifies GT928 that data reading is compl ete. GT928 will automatically switch to receive mode and will not start transmitting until transmit buffer is flushed again. _linu(
10-point capacitive touch controller GT928 14 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 8.description on functions 8.1 operating modes d) normal mode when GT928 is operating in normal mode, its coordinate refresh period is configurable (5ms to 20ms valid, one step is 1ms). when no touch is detected for a certain period (0s to 14s, subject to configuration; one step is 1s) in normal mode, GT928 will automatically switch to green mode to reduce power consumption. _linu(
10-point capacitive touch controller GT928 15 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. e) green mode in green mode, the scanning period for GT928 is about 40ms. it automatically enters normal mode if any touch is detected. f) gesture mode after the host enables GT928 to enter gesture m ode by sending i2c command 8 to 0x8046 and then to 0x8040, wake-up can be achieved by swipe, double-tap, or writing of specified letters on tp. in gesture mode, when GT928 detects any finger swipe f or a sufficiently long distance, double-tap or writing of specified letters on tp, int will output a pulse for longer than 250us or output a high level. after receiving such pulse or level, the host wakes up and turns on the screen. g) sleep mode GT928 enters sleep mode if it receives the corresponding i 2 c command from the host (require int output low before the command). GT928 exits s leep mode and enters normal mode when host outputs a high level to int pin for 2ms to 5ms. the interval between sending screen-off command and wake-up should be longer than 58ms. h) approach mode when hotknot proximity detection is enabled, GT928 is operating in approach mode by default. if GT928 exit approach mode, the host can send command 0x20 or 0x21 to enable GT928 to enter approach mode again. in this mode, touc h detection and hotknot proximit y detection alternate. if the host sends 0x21 to GT928, GT928 will work as a trans mitting terminal and transmit signals with a specified pattern and frequency via tx and rx channels. then, GT928 detects whether there are feedback signals with the same specified pattern and frequency from the receiving terminal. this helps to determine whether any receiving termi nal exists. if the host sends 0x20 to GT928, GT928 will work as a receiving terminal and detect signals with a specifie d pattern and frequency from the transmitting terminal. if such a s ignal is detected, GT928 responds u sing signals with the specified pattern and frequency to the transmitting terminal . in approach mode, when detecting any hotknot- compatible terminal within the near-field range, GT928 will notify the host via int to capture status. to _linu(
10-point capacitive touch controller GT928 16 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. ensure reliable detection between th e transmitting terminal and the receiving terminal, it is required to keep detecting for a minimum of 150ms after the tw o terminals have detected each other. then the host sends hotknot transmission firmwar e to enable GT928 to enter receive mode. i) receive mode in approach mode, after notified that GT928 has succ essfully detected anothe r hotknot-compatible terminal, the host sends hotknot transmission fir mware to enable GT928 to enter receive mode. in receive mode, GT928 continues to detect frame st art signal, once the signal is detected, GT928 begins to detect and receive data. when the receivi ng process is complete, GT928 verifies the data. if GT928 finds erroneous data, the receiving proc ess begins again. if the data is found to be correct, GT928 notifies the host via int to read data in the receive buffer. j) send mode when GT928 works in receive mode, the host s ends outgoing data to the transmit buffer. when detecting that the transmit buffer is flushed and there is data to be sent, GT928 automatically switches from receive mode to send mode. in send mode, GT928 sends a frame start signal. if it detects ack fed back from the receiving terminal, i t continues to send the data signal. after sending a data chunk, GT928 begins to detect ack. if it does not detect any ack or if it detects an erroneous ack, GT928 will resend the data chunk. if this resend ing fails over 5 times, it will resend the current data frame another time to the receiving terminal until the host enables GT928 to exit send mode due to timeout. if GT928 detects ack and sends the dat a successfully, it will automatically switch to receive mode after the host completes the data processing or due to timeout. 8.2 interrupt triggering mechanism when touched, GT928 sends a pulse via int pin in e very scanning cycle to notify the host to read coordinates. host will then set a tri ggering mechanism via relevant regist er ?int? bit. int as ?0? indicates rising edge-triggered, which means GT928 will notify the host by driving int output from low to high when operated by user; int as ?1? indicates falling edge-triggered, which means GT928 will notify the host by driving int output from high to low when operated by user . 8.3 sleep mode when the touch screen is off or there are no running operations on the tp, the host sends i 2 c command to enable GT928 to enter sleep mode, whic h reduces power consumption. when GT928 needs to operate, the host outputs a high level to int pi n for a certain period to awake it. for detailed timings of host enabling GT928 to enter and exit sleep mode, please refer to section 8.1. 8.4 stationary configuration GT928 supports stationary configuration. after receiving configuration parameters from the host, GT928 will fix parameters to the latest versi on. once these parameters are fixed, GT928 will _linu(
10-point capacitive touch controller GT928 17 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. communicate with the host solely via i2c bus and will not receive any parameters of previous versions from the host. 8.5 self-calibration k) self-calibration during initialization fluctuations in temperature, humidity and envir onment may affect the baseline of the capacitive sensor in idle state. GT928 will update detection baseline according to environmental conditions within the first 200ms of initialization. then, GT928 will finish the initialization of the tp test. l) automatic drift compensation gradual changes in environmental factors such as te mperature, humidity, or dust may also affect the baseline of the capacitive sensor in idle stat e. GT928 will detect real-time changes in data and perform statistic analysis of historic data to revise baseline and thus reduce the impact that environmental changes have on the tp test. 8.6 finger touch and stylus touch transition m) finger touch in finger touch state, software narrows the touch signal to locate the touch position, which reduces noise. n) stylus touch GT928 detects the touch signal in every cycle. when valid stylus touch signal is detected, GT928 enters stylus touch state. in this state, GT928 locates the touch position with the sampled touch signal and finger touch signal and other touch signals will be suppressed. only the valid stylus touch will be reported. _linu(
10-point capacitive touch controller GT928 18 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 9.sample schematic the v oltage vddio sets the logic lev el. when vddio is connected to avdd directly , the logic lev el is avdd, otherwise, logic lev el is 1.8v. sensor_opt1 and sensor_opt2 are sensor id pins. six dif f erent kinds of connection method can distinguish among 6 module manuf acturers. sensor id numbers 0-5 indicate 6 module manuf acturers respectiv ely . sensor_opt2 cannot be lef t f loating. /rst c6 1nf r7 680 int int_a /rst avdd to enable "gesture wake-up" f unction, this circuit should be connected to int pin. drv0 drv1 drv3 drv2 drv8 drv6 drv5 drv4 drv7 drv9 drv12 drv13 drv11 drv10 drv15 drv14 drv17 drv18 drv16 drv21 drv20 drv19 drv22 drv23 drv28 drv26 drv25 drv24 drv27 avdd18 avdd dvdd12 sens6 sens5 sens16 sens17 sens19 sens18 sens0 sens1 sens21 sens20 sens3 sens2 sens23 sens22 sens5 sens4 sens7 sens6 sens9 sens8 sens11 sens10 sens8 sens12 sens9 sens10 sens_key 3 sens14 sens11 sens13 sens_key 4 drv_key sens15 sens_key 2 sens_key 1 key 1 1 2 key 2 1 2 key 3 1 2 key 4 1 2 sensor id connection methods f or cob sensor id connection methods f or cof s_opt2 gnd vddio nc gnd gnd gnd nc nc nc vddio s_opt1 nc gnd gnd s_opt2 gnd nc vddio opt1 300k gnd gnd 300k 300k gnd nc vddio 1 s_opt1 module ? id 2 sensor ? id 5 0 3 1 sensor ? id 4 2 0 5 4 3 module1 module4 module3 module2 module ? id module6 module5 module2 module1 module5 module4 module3 module6 drv29 opt2 sens15 sens12 sens13 sens14 j1 sens interf ace 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 drv31 drv30 j2 drv interf ace 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 u1 GT928 avdd28 18 avdd18 19 dvdd12 20 dgnd 21 int 22 sensor_opt1 23 sensor_opt2 24 i2c_sda 25 i2c_scl 26 vddio 27 rstb 28 drv0 60 drv1 59 drv2 58 drv3 57 drv4 56 drv5 55 drv6 54 drv7 53 drv8 52 drv9 51 drv10 50 drv11 49 drv12 48 drv13 47 drv14 46 drv15 45 drv16 44 drv17 43 drv18 42 drv19 41 drv20 40 drv21 39 drv22 38 drv23 37 drv24 36 drv25 35 drv26 34 drv27 33 drv28 32 drv29 31 ep 69 agnd 61 sens0 62 sens1 63 sens2 64 sens3 65 sens4 66 sens7 1 sens8 2 sens9 3 sens10 4 sens11 5 sens12 6 sens13 7 sens14 8 sens15 9 sens16 10 sens17 11 sens18 12 sens19 13 sens20 14 sens21 15 sens22 16 sens23 17 sens5 67 sens6 68 drv30 30 drv31 29 q f n 8 x 8 - 6 8 l - 0 . 4 p r2 10k vddio drv30 drv31 avdd18 avdd c1 2.2uf c4 2.2uf vddio c3 2.2uf dvdd12 c5 10nf c2 2.2uf sens16 sens17 sens18 sens20 sens19 sens22 sens21 sens23 j3 host interf ace 1 2 3 4 5 6 channel selector. key design rules: 1.support at most f our touch key s.select a maximum of 4 sensing channels as sens_key and select one separate driv ing channel as drv_key . 2.the sensing channels used by key s must be shared with the touch panel. 3. for drv_key selection, please ref er to tool opt1 unused sens or drv pins can be lef t f loating. for channel selection, please ref er to tool channel selector. drv0 drv1 drv3 drv2 drv5 drv4 drv6 drv7 drv9 drv8 drv10 drv11 drv12 drv25 drv20 drv23 drv22 drv24 drv16 drv18 drv19 drv21 drv13 drv14 drv15 drv17 interf ace sequence (f or ref erence only ) opt2 connection methods for cof. pay attention to sensor id list on the right. opt2 pins cannot be left floating. module opt 2 connect ion met hods for cob. t he 300k ? resistor connected to opt2 should be placed on the main board, in case the opt2 node is left floating when it is not connected to the touch panel. main board drv29 drv27 drv26 drv28 s_opt2 2 1 3 300k opt2 s_opt2 2 1 3 r6 300k opt2 sens7 sens4 sens3 sens1 sens0 sens2 if there are pull-up resistors on the host i2c bus, these two pull-up resistors on the module should be remov ed. size project name rev date: sheet of shenzhen huiding technology co.,ltd. GT928 2.2 custom 11 tuesday , nov ember 11, 2014 vddio s_opt1 avdd jump1 2 1 3 vddio r5 2k r4 2k /rst i2c_scl i2c_sda int_a int i2c_scl i2c_sda vddio GT928 sample schematic note: z this schematic only represents bas ic application. adjustments may be required to fit in with actual situations and app lication environments. z it is recommended that the capacitor be ceramic x7r. _linu(
10-point capacitive touch controller GT928 19 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 10. electrical characteristics 10.1 absolute maximum ratings (ambient temperature: 25 ) parameter min. max. unit analog power avdd28 (please refer to agnd) 2.66 3.47 v vddio (please refer to dgnd) 1.7 3.47 v voltage acceptable to digital i/o -0.3 3.47 v voltage acceptable to analog i/o -0.3 3.47 v range of operating temperature -40 85 range of storage temperature -60 125 welding temperature (10s) 300 esd protection voltage (hb model) 2 kv 10.2 recommended operating conditions parameter min. typ. max. unit avdd28 2.8 - 3.3 v vddio 1.8 - 3.3 v operating temperature -20 25 85 10.3 ac electrical characteristics (ambient temperature:25 , avdd=2.8v, vddio=1.8v) parameter min. typ. max. unit osc oscillation frequency 59 60 61 mhz i/o output rise time, low to high -1 4 -n s i/o output fall time, high to low -1 4 -n s _linu(
10-point capacitive touch controller GT928 20 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 10.4 dc electrical characteristics (ambient temperature:25 , avdd=2.8v) parameter min. typ. max. unit normal mode operating current - 13 ma green mode operating current - 4.5 - ma sleep mode operating current 70 120 ua doze mode operating current 1.2 ma input low voltage/vil -0.3 0.25*vddio v input high voltage/vih 0.75*vddio vddio+0.3 v output low voltage/vol 0.15*vddio v output high voltage/voh 0.85*vddio v _linu(
10-point capacitive touch controller GT928 21 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 11. package symbol dimensions in millimeters min. normal max. a 0.70 0.75 0.80 a1 0.00 0.035 0.05 b 0.40bsc d 8.00bsc d1 5.40 5.50 5.60 e 8.00bsc e1 5.40 5.50 5.60 e 0.15 0.20 0.25 l 0.30 0.40 0.50 k 0.203bsc _linu(
10-point capacitive touch controller GT928 22 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 12. revision history revision date description rev.00 2012-09-13 preliminary release rev.01 2012-09-20 modified the power-o n timing and dc characteristics rev.02 2012-10-26 modified register map; modified description on stat ionary configuration function; modified dc characteristics; updated sample schematic. rev.03 2012-12-08 modified operating and storage temperatures; modified power consumption of different modes; rev.04 2013-04-01 modified the typical value of green mode operating current rev.05 2013-09-12 modified the sensor design parameters modified iic communication parameters modified power-on timing modified frequency hopping and passive stylus configuration modified operating mode switchover chart modified description on sleep mode and wakeup timing added description on passive stylus updated sample schematic modified absolute maximum ratings rev.06 2014-07-18 updated power-on and reset timings rev.07 2014-10-13 added hotknot to product features modified pin definitions updated iic address selection timing deleted register map modified operating modes switchover chart added description on gesture mode and hotknot modified dc characteristics rev.08 2014-11-14 updated sample schematic modified electrical characteristics _linu(
10-point capacitive touch controller GT928 23 goodix confidential reproduction and/or distribution of this document in whole or in part is strictly prohibited without written consent of goodix. 13. contact information shenzhen huiding technology co., ltd. floor 13, phase b, tengfei industrial building, futian free trade zone shenzhen 518000 tel+86-755-33338828 fax+86-755-33338828 www.goodix.com _linu(
our company network supports you worldwide with offices in germany, great britain, italy, turkey and the usa. for more information please contact: distec gmbh augsburger str. 2b 82110 germering germany phone: +49 (0)89 / 89 43 63 - 0 fax : +49 (0)89 / 89 43 63 - 131 e - mail: info@datadisplay - group.de internet: www.datadisplay - group .de display technology ltd. 5 the oaks business village revenge road, lordswood chatham , kent, me5 8lf united kingdom phone: + 44 (0)1634 / 67 27 55 fax: + 44 (0)1634 / 67 27 54 e - mail: info@ data display - group .co.uk internet: www.datadisplay - group.co.uk apollo display technologies, corp. 87 raynor avenue, unit 1ronkonkoma, ny 11779 united states of america phone: +1 631 / 580 - 43 60 fax: +1 631 / 580 - 43 70 e - mail: in fo@datadisplay - group.com internet: www. data display - group .com sales partner: sales partner: rem italy s.a.s. di michieletto flavio & c. via obbia bassa, 10 i - 35010 trebaseleg he (pd) ital y phone: +39 335 521 37 89 e - mail: info@remitaly.com internet: www.remitaly.com data display b?l???m teknoloj?ler? ?? ve di? t?caret l?m?ted ??rket? barbaros mh . ak zamabak sk . a blok d:143 34376 ata?ehir / i stanbul t urkey phone: +90 (0)21 6 / 688 04 68 fax: +90 (0)21 6 / 688 04 6 9 e - mail: info@ data - display .com.tr internet:www. data - display .com.tr

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