AR1000 Datasheet, PDF (14/37 Pages) Microchip Technology – Resistive Touch Screen Controller

Figure 12 : SPI Timing Diagram – Touch Report Protocol
Figure 13 : SPI Timing Diagram – Command Protocol
7.7.3 UART
The SDO pin is not used and must be left as a “no connect”. Do NOT tie it directly to VSS or VDD.
UART communication is at a fixed 9600 baud rate.
7.8 Status LED
The LED and associated resistor are optional.
The LED serves as a status indicator that the controller is functioning. It will slow flash when the controller is
running with no touch in progress. It will flicker quickly (mid level On) when a touch is in progress.
If the LED is used with SPI communication, then the LED will be off with no touch and flicker quickly (mid level
On) when a touch is in progress.
If the SIQ pin is not used, it must be left as a no connect and NOT tied to circuit VDD or VSS.
DS41393A-Page 10
© 2009 Microchip Technology, Inc.