lpcware

Tearing on LCD when accesing USB

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by larsjep on Mon Mar 24 05:47:21 MST 2014
Hi,

I'm having a problem with tearing on the LCD display.
The tearing occurs when I transfer data to and from a USB stick.
(On USB0 High-speed mode)

The display resolution is 800x480 16bit
The memory is 2x16MB (32bits bus) SDRAM running at 102Mhz.
The CPU core is running at 204Mhz.

It seems like the USB DMA is disturbing the LCD DMA.

I have tried to lower the DMA burst size of the USB controller with register BURSTSIZE, but I can't change these values. It keep going back to 0x1010 which is default.

Is it possible to lower the DMA priority of the USB controller somehow ?
Any ideas on how to solve this ?


Best regards
  Lars

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