On my current project I writing images to a TFT display. When the unit is powered from the battery there is flickering and movement of the screen in the vertical direction. There are test points on the flex cable going to the screen and if I touch the VSYNC (for vertical sync) point with my oscilloscope probe the screen stops bouncing and the looks great!
When I remove the probe the flickering / bouncing continues!
Then if I plug in my A/C adapter to the unit the screen stops flickering and looks great also!
I have tried adding more and more capacitance to the VSYNC line but this doesn't seem to help. All the voltages going to the screen are the same when I have bouncing, touching with the probe, and plugging in the A/C adapter.
Any thoughts no debugging this?
Thanks.
-Mike