CRTOUCH Datasheet, PDF (28/68 Pages) Freescale Semiconductor, Inc – Capacitive and Resistive Touch Sensing Application Specific IC.

Memory Map and Registers Description
4 Memory Map and Registers Description
The CRTouch product has status and configuration registers for the resistive touchscreen driver and the capacitive keys support.
All the status registers are read-only registers. The configuration registers have read and write attributes. All configuration
registers are stored in non-volatile memory when changed, the device therefore does not require reconfiguration after power
loss or reset. Only specific bits in certain registers are not restored and this is indicated in the corresponding bit description.
When writing a configuration value into a register, it may take one sampling period, resistive or capacitive, for it to take effect
and to be read.
4.1 Device memory map
The CRTouch memory map is designed to allow a consecutive bytes reading. Each register has a value for its incremental
address, which is the value that the internal read address pointer holds after reading that specific location. For example, if the
X coordinate is read, the initial transaction starts with address 0x03 and automatically auto-increment to 0x04, 0x05, and 0x06.
When the pressure is disabled, after reading the Y coordinate LSB in address 0x06, the internal address pointer returns to value
0x03 to allow reading again of X and Y coordinates without further write operations.
Name
Resistive Touch Error
Register
Table 8. Resistive touch sense status register map
Register Incremental
address Address
0x00
0x01
Default Value
0x00
Valid Range
—
Resistive Touch Status
Register 1
Resistive Touch Status
Register 2
X coordinate MSB
X coordinate LSB
Y coordinate MSB
Y coordinate LSB
0x01
0x02
0x03
0x04
0x05
0x06
Pressure value MSB 0x07
Pressure value LSB
0x08
Resistive Touch FIFO
Status
0x09
FIFO X coordinate MSB 0x0A
FIFO X coordinate LSB 0x0B
FIFO Y coordinate MSB 0x0C
FIFO Y coordinate LSB 0x0D
FIFO Pressure value
coordinate MSB
0x0E
0x02
0x03
0x04
0x05
0x06
0x03¹
0x07²
0x08
0x03
0x0A
0x0B
0x0C
0x0D
0x0A¹
0x0E²
0x0F
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
—
—
0x00 – 0x1F
0x00 – 0xFF
0x00 – 0x1F
0x00 — 0xFF
0x00 — 0xFF
0x00 — 0xFF
—
0x00 — 0x1F
0x00 — 0xFF
0x00 — 0x1F
0x00 — 0xFF
0x00 — 0xFF
Comment
Used to report Serial
Protocol communication
errors
Register used to report
general information
Register used to report
general information
X coordinate MSB
X coordinate LSB
Y coordinate MSB
Y coordinate LSB
Pressure value MSB
Pressure value LSB
FIFO Status information
FIFO X coordinate MSB
FIFO X coordinate LSB
FIFO Y coordinate MSB
FIFO Y coordinate LSB
FIFO Pressure value
coordinate MSB
CRTouch Data Sheet, Rev. 3
28
Freescale Semiconductor