When in standby you can (in theory) control the LED, it has 2 modes when the display power is off:

- Pulsing (default)
- Controlled by host

In theory, if you set up interrupts and timers you could make it do anything; however this requires disabling of the LCD controller on the StrongARM and it's sometimes hard (been a while since I tried though...) to get everything to sync correctly when it comes up again.

Hugo