Problem with MPC823 LCD driver

[Richard Hendricks]

That could be it.  One obvious indicator is that without LCD and
the caches disabled, everything works fine.  If it breaks with the
caches turned on, check your UPM burst tables.  This is where most
mistakes occur.  Also, be sure to bring all the UPM signals back
high at the end of your transactions.

Dan Malek wrote:
>
> Kim Jørgensen wrote:
>
> > I got a custom MPC823E board, and I want to use a LCD display with Linux.
>
> Get the logic analyzer on the bus.......
>
> > Can anyone tell me what is wrong, and how to solve this?
>
> I can make a few guesses.  This has nothing to do with Math Emulation,
> and everything to do with fetching the proper instructions into the
> core.  The LCD controller is a heavy-duty DMA controller that has
> priority over everything to ensure it can keep the display updated
> from system memory.  Since the controller performs large burst mode
> operations, this is a classic example of memory controller or memory
> interface problems.  I suspect the memory timing isn't correct and the
> instructions are just bad memory cycles that can't be properly
> decoded.
>
>         -- Dan
>

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MPC823 Applications Engineering Development

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