ColdFire/68K Microcontrollers and ProcessorsのトピックRe: Problem with the frame buffer of MCF5329

Problem with the frame buffer of MCF5329

Dome — Tue, 14 Oct 2008 22:56:02 GMT

Hi,

when I use the MCF5329 with a resolution of 800x480, I have the follow problem:
if the frame buffer is black (ex.: "cat /dev/zero > /dev/fb0") the throughput over ethernet is about zero, it's diffucult to ping the board. Instead if the frame buffer is colored or white better the throughput is ok, we arrived about to 10 Mbit/s.
Why there is this difference?

Thanks
Bye
Dome

Re: Problem with the frame buffer of MCF5329

obidon — Mon, 10 Nov 2008 23:24:39 GMT

You might check your crossbar switch module priorities XBS_PRS1. I know with a 640 x 480 LCD running 18bpp it is necessary to boost the LCD controller priority to prevent steaks on the display. This slows everything else. For our current project we are using 8bpp with a lower priority on the LCD controller.