Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
DS41393B-page 36 Preliminary  2009-2012 Microchip Technology Inc.
9.1.3 DISABLE TOUCH BEFORE
SENDING SUBSEQUENT
COMMANDS
The AR1000 does not support full duplex
communications. It cannot send touch reports to the
host simultaneously with receiving commands from the
host.
Disable AR1000 touch reporting prior to sending any
other command(s), then re-enable touch reporting
when complete with executing other commands.
1. Send the DISABLE_TOUCH command.
Check for expected command response.
2. Send a desired command.
Check for expected command response.
3. Repeat at step 2 if another command is to be
sent.
4. Send the ENABLE_TOUCH command.
Check for expected command response.
9.1.4 CONFIRM COMMAND IS SENT
Confirm each command sent to the AR1000, prior to
issuing another command, to ensure it is executed.
This is accomplished by evaluating the AR1000
response to a command that has been sent to it.
Check for each of the following five conditions to be
met (See Tabl e 9-4).
0x<> represents a value that is dependent on the com-
mand.
An error has occurred if no response is received at all
or if any of the above conditions are not met in the
response from the AR1000. If an error condition
occurs, delay for a period of ~50 ms then send the
same command again.
TABLE 9-4: COMMAND RESPONSE ERROR CONDITIONS
Condition Response Byte Description
Header 1 Header 0x55 value is expected
Size 2 Size 0x<> value to match what is expected for command sent
Status 3 Status 0x00 “success” value is expected
ID 4 Command ID 0x<> value to match what is expected (ID of sent command)
Data 5 to end Data byte count to match what is expected for command sent