Is it possible to use the OVLY bit in the PMST register to do
swapping of memory pages between the internal memory of a C5410 and a
flash chip?? The board that I am working with has a flash chip mapped
to the same areas as the C5410 memory and I don't have a clue yet on
how to divide and use all the memory appropiately. Please any help on
this issue will be greatly appreciated.
OVLY and Memory Paging
no, normally you don't use ovly for that.
there must be another trick to swap the flash/memory?
is it e specturm evm?
> -----Original Message-----
> From: jhlucena [mailto:]
> Sent: dinsdag 8 januari 2002 20:54
> Subject: [c54x] OVLY and Memory Paging > Hello,
> Is it possible to use the OVLY bit in the PMST register to do
> swapping of memory pages between the internal memory of a C5410 and a
> flash chip?? The board that I am working with has a flash chip mapped
> to the same areas as the C5410 memory and I don't have a clue yet on
> how to divide and use all the memory appropiately. Please any help on
> this issue will be greatly appreciated.
> SW. Engineer >
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The OVLY bit makes the internal DARAM visible in program space also- so you
execute code from it. When the bit is set, all program space accesses from
internal, 4000-FFFF are external. Since your flash is probably at 0000-FFFF,
see the first 16K in this mode. If you turn off OVLY, all program accesses
external; however you have no internal program memory for fast (0 wait state)
I think the best solution is to swizzle the address bits and map your external
say 8000-FFFF and 18000-1FFFF for instance so it's all visible while running in
Since the hardware is already fixed though, you could set up manual paging as
turn off OVLY
MVPD to copy code block from ext Program flash to int Data space
turn on OVLY (int data space becomes int program/data space)
call code using appropriate entry point; runs from internal Program space
The key here is that the 54x doesn't really care whether the software is
internal mem as program or data, so after you've copied, it's at the same
your responsibility to know the code entry points and keep your sections