USB FIle download ->''Snow'' on LCD

Johanan1 · ‎2015-02-14

Posted on February 14, 2015 at 16:33

Using USB and FATFS, I am downloading a large file from USB to external flash (approx 2 MB), during download, I can see small random ''snow'' white pixels on LCD screen.

The file download is a separate FreeRTOS task, with no GUI interface whatsoever.

What could be the problem? do I need to make some synchronization between USB activity and LCD controller? (It could be due to bus issue as the frame buffer and flash are external memories)

Johanan

AvaTar · ‎2015-02-16

Posted on February 16, 2015 at 13:22

I'd guess either power issues (with supply voltage drops), or interrupt load issues, if you clock the display directly from a MCU peripheral.