Pixels problem

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by DT1 on Fri Jan 31 14:56:54 MST 2014

I currently using the MCB4357 dev board. I have a custom application using emWin. When I try to draw something on the screen, some pixels don't behave correctly. The pixels are always the same, but their behavior is not constant.

For example, let's say I have those pixels that are problematic:
- Pixel 1 (located at some x and some y)
- Pixel 2 (located at some x and some y)
- Pixel 3 (located at some x and some y)
- Pixel 4 (located at some x and some y)

- Execute action 1 (redrawn the whole screen)
- Pixels are ok
- Execute action 2 (draw a small bitmap image somewhere in the screen)
- Pixel 2 is black instead of white, others are ok.
- Execute action 3 (draw a small bitmap image at another place in the screen)
- Pixel 2 is ok
- Pixel 1, 3 and 4 are black instead of white.

If I redo the above, the same pixels will behave wrongly, but not necessarily in the same order. What I have in mind is a problem with the SDRAM or maybe one of the RGB trace, but my dev board is brand new and I have this problem on another MCB4357 too.

Any suggestion on where to look?