Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER

DS41393B-page 20 Preliminary  2009-2012 Microchip Technology Inc.

4.8 Touch Report Protocol

Touch coordinates, when available, are provided to the

master by the AR1021 in the following protocol (See

Figure 4-3).

FIGURE 4-3: I

C TOUCH REPORT PROTOCOL

Note that the IRQ signal shown above occurs on the

SDO pin of the AR1021.

4.9 Command Protocol

The master issues supported commands to the

AR1021 in the following protocol.

Below is an example of the ENABLE_TOUCH command

(see Figure 4-4).

FIGURE 4-4: I

C COMMAND PROTOCOL

Note that the IRQ shown above occurs on the SDO pin.

• 0x9A AR1021 Device ID address

• 0x00 Protocol command byte (send 0x00 for

the protocol command register)

• 0x55 Header

• 0x01 Data size

• 0x12 Command

4.10 Sleep State

Pending communications are not maintained through a

sleep/wake cycle.

If the SDO pin is asserted for a pending touch report or

command response, and the AR1021 enters a Sleep

state, prior to the master performing a read on the data,

then the data is lost.