stmpe812a STMicroelectronics, stmpe812a Datasheet - Page 36

• Manufacturer Part Number: stmpe812a
• Description: S-touch? Enhanced 4-wire Resistive Touchscreen Controller With Pwm And Dedicated Reset Pin
• Manufacturer: STMicroelectronics

Touchscreen controller
TSC sampling rate
Address:
Type:
Reset:
Description:
TSC_data
Address:
Type:
Reset:
Description:
Note:
36/52
TSC_DATA_7 TSC_DATA_6 TSC_DATA_5 TSC_DATA_4 TSC_DATA_3
7
0
7
0
In order to preserve the integrity of the data, it is mandatory to ensure the following:
- System host to read exactly the number of bytes according to the programmed operating
mode
- I2C host to insert a STOP condition after each data read command
Data pointer in this 1-level buffer could be reset by:
-User issued ACQ in user initiated acquisition mode. In mode ‘10’, every time sampling is
completed, it overwrites the buffer, and reset the data pointer
[7:0] Sampling[7:0]
[7:0] TSC_DATA_x: Data byte from touchscreen controller.
6
0
6
0
0x43
R/W
0x0A
Touchscreen controller sampling rate control register.
Sets the sampling rate of touchscreen controller.
Sampling Time = (sampling[7:0]+1) in ms
Clock cycle = 1 µs (1 MHz RC OSC)
Sampling time = 1 ms – 256 ms
NOTE:
This is used as “TSC regular initiator signal’. As long as there remains a valid touch, every
interval of this timing, the touchscreen controller executes a complete drive/settling/multi-
sample/MAV/data calculation. It is the user’s responsibility to choose a sampling time that is
enough, based on ADC_FREQ, settling time and filter.
0x42
R/W
0xB0
The data format of the touchscreen controller data register depends on the setting of
“OpMode” field in the touchscreen detection configuration 2 register. The samples
acquired are accessed in “packed samples”. The size of each “packed sample”
depends on which mode the touchscreen controller is operating in.
5
0
5
0
4
0
4
0
Doc ID 18225 Rev 2
SAMPLING
3
1
3
0
TSC_DATA_2
2
0
2
0
TSC sampling rate register
Touchscreen data register
TSC_DATA_1
1
1
1
0
STMPE812A
TSC_DATA_0
0
0
0
0