CRTOUCH Datasheet, PDF (27/68 Pages) Freescale Semiconductor, Inc – Capacitive and Resistive Touch Sensing Application Specific IC.

Serial Communications
Table 6. UART communication responses to a write command
Byte Value
0xC2
0xE0
0xE1
0xE2
0xE3
0xE5
Information
Positive Acknowledge. The last command data was valid and has been properly
written into CRTouch.
Sampling rate out of range. A value between 5 and 100 (ms) is expected.
Invalid write transaction. Register written does not have write attributes
Data size out of range. A value between 1 and tes sent in the write command
Register Address out of range. See memory map section for more information
Parity Error was generated. Parity is odd parity for each byte.
3.2.4 Registers Write through UART
To write one to n CRTouch registers, the communication must start with a SOF, followed by a register address with the most
significant bit value of ‘1’ indicating the amount of registers to be written, followed by the data bytes and ending with an EOF.
The CRTouch will reply either with an acknowledge byte or an error code.
Figure 24. Register write through UART communication
The following table shows a list of possible responses to a write commands from a host. Response to any write command is the
only communication where the communication protocol is not strictly followed to reduce the amount of traffic generated for a
simple acknowledgement.
Table 7. UART communication responses to a write command
Byte Value
Information
0xC2
0xE0
0xE1
0xE2
0xE3
0xE5
Positive Acknowledge. The last command data was valid and has been properly written into CRTouch.
Sampling rate out of range. A value between 5 and 100 (ms) is expected.
Invalid write transaction. Register written does not have write attributes
Data size out of range. A value between 1 and test sent in write command
Register Address out of range. See memory map section for more information
Parity Error was generated. Parity is odd parity for each byte.
CRTouch Data Sheet, Rev. 3
Freescale Semiconductor
27