GOODIX CONFIDENTIAL
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2.2 Timing for Read Operation
First, set register address from which Read Operation starts based on the aforesaid Wirte Operation timing
sequence. Then, resend start condition to perform Read addressing and read register data.
Address_R: Slave device address with Read control bit.
NACK: Host issues NACK after reading the last byte.
After setting read operation register addresses, the host can read one or more than one byte at a time. GT911
will automatically increase register address and send subsequent data in sequence.
The stop condition (the first E signal as shown in the above diagram) after setting read operation register
address is optional. However, the start condition to restart I
2
C communication has to be resent.
3. Register Map
3.1 Real-time command (Write only)
Addr
Name
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
0x8040
Command
0: Read coordinates status; 1: Read diff data or raw data; 2: Read diff data or raw data;
3: Reference capacitance update (Internal test); 4: Reference capacitance calibration
(Internal test); 5: Screen off;
6: Enter Charge mode; 7: Exit Charge mode
8 : Gesture mode.
0x20: Enter HotKnot Slave Approach mode
0x21
：
Enter HotKnot Master Approach mode
0x22
：
Enter Receive mode
0x28
：
Exit Slave Approach mode
0x29
：
Exit Master Approach mode
0x2A
：
Exit Receive mode
0xAA: ESD protection mechanism enabled; driver writes 0xAA to 0x8040 and reads
and checks the value of 0x8040 regularly; other values are invalid.
0x8041
ESD_Check
ESD protection mechanism enabled; reset to 0 upon initialization; after that, driver
writes 0xAA to 0x8040 and reads and checks the value of 0x8040 regularly.
0x8046
Command_Check
For commands greater than 0x07, it is required to write the command to 0x8046 before
writing to 0x8040, to improve anti-ESD capability.
