uclinux on a 800x600 TFT

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When I run my programs, there are horizontal lines of garbage on the screen.

This is my system configuration:
   Motorola MC5372C3 board with the ColdFire processor running at 66MHz
   A graphical board with the Epson s1d13806 graphic controller
   Unipac 800*600 TFT touch panel
   uClinux 2.4 with a framebuffer driver for the s1d13806

The s1d13806 clocks I am using just now (I have tested several
combinations) are:
   BUSCLK = 66MHz
   MCLK = CLK1 = 40MHz
   LCDCLK = CLK1 = 40MHz

The s1d13806 technical information talks about screen corruption but
only in stress conditions (affecting internal bandwidth) greater than
mine. Even so, changing the fifo threshold registers and the SDRAM
Control timing registers of the s1d13806 we got only a few lines but
they are still there. If we write only on the non vertical display, the
image are always clean, but the system gets too slow.

I am puzzled nobody gets a problem like this (at last i found no
references on the net), and I see several boards on the net saiyng they
work at such speeds. So, I thinkl I must be missing something trying to
get the s1d13806 to work. But I can not think of anything more to try.

Any idea will be welcome.


Re: uclinux on a 800x600 TFT

Epson asks me to raise the power supply 200mv. We was at 3.29 and
raise it to 3.46. The corruption get worst. Since the supply affected
so much to the chip, we trid with another source of power and ... the
screen went clean at whatever power supply voltage (into the permited

The problenm seems to be at the start. The board supply gets to the
3.28V very fast: 1ms. The external source goes very slowly: 35 ms.

There is something at the start that affects the s1d13806 behaviour.
And to do a system reset does not resolve the problem.

Any idea?

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