DS41393A-Page 10

© 2009 Microchip Technology, Inc.

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.