Forum Post: AM3352 GPMC_AD8~15 use problem (low/high changed)

Hi all,

 I want to use the GPMC_AD8~15 as output to driver LED on my own board. when power on the board, found an intresting phenomenon, the LED can blink  automatically. And when i connect the board using CCS ,the LED will be off.The circuit as follows,

Capture the wave on GPMC_AD8 ,  there is an about 2V  signal and cycle is about 3 seconds.

I wonder why the GPMC_AD8 will low/high changed automatically? Is there some "inner code" work?

Any suggestion will be appreciated,thanks!

Stone