AR1000_16 Datasheet, PDF (42/61 Pages) Microchip Technology – AR1000 Series Resistive Touch Screen Controller

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
10.2.2
EXECUTION OF FIXED
CALIBRATION VALUE LOADING
Follow error checking practices by checking the
AR1000 responses to issued commands.
1. Send the AR1000 DISABLE_TOUCH command.
2. Use the AR1000 EEPROM_WRITE command
multiple times to write the following to the
AR1000 EEPROM.
a. Block Key 0x55 to address 0x16
b. Data set to addresses 0x17:0x27. See
Section 9.3.4.3 “Calibration Data
Encoded and Stored in EEPROM” and
Section 9.3.12 “EEPROM Map”.
c. Checksum for the data block to address
0x28
d. Mirror image of a, b and c from above to
address 0x3E:0x50
3. Set the CCE bit of the TouchOptions register.
This will enable the controller to use the
calibration data on the next power boot. See
Section 10.2.3 “Configuring the CCE bit to
Use Fixed Calibration Values” for additional
details on the CCE bit.
4. Send the AR1000 ENABLE_TOUCH (0x12)
command.
10.2.3
CONFIGURING THE CCE BIT TO
USE FIXED CALIBRATION VALUES
The CCE bit of the TouchOptions Register (offset
0x0D) must be set to ‘1’ to enable the usage of the
stored calibration values in EEPROM.
This should be completed before re-enabling the
controller via the ENABLE_TOUCH command.
REGISTER 10-1: CCE BIT FORMAT
U-0
U-0
U-0
U-0
U-0
U-0
R/W
—
—
—
—
—
—
48W
bit 7
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
bit 7-2
bit 1
bit 0
Unimplemented: Read as ‘0’
48W: 4-Wire or 8-Wire Sensor Selection bit
1 = Selects 8-wire Sensor Operating mode
0 = Selects 4-wire Sensor Operating mode
CCE: Calibrated Coordinates Enable bit
1 = Enables calibrated coordinates, if the controller has been calibrated
0 = Disables calibrated coordinates
R/W
CCE
bit 0
DS40001393C-page 42
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