The OVLY bit makes the internal DARAM visible in program space also- so you can load and execute code from it. When the bit is set, all program space accesses from 0000-3FFF are internal, 4000-FFFF are external. Since your flash is probably at 0000-FFFF, you won't see the first 16K in this mode. If you turn off OVLY, all program accesses 0000-FFFF are external; however you have no internal program memory for fast (0 wait state) execution. I think the best solution is to swizzle the address bits and map your external flash to say 8000-FFFF and 18000-1FFFF for instance so it's all visible while running in OVLY mode. Since the hardware is already fixed though, you could set up manual paging as follows: 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 treating the internal mem as program or data, so after you've copied, it's at the same address. Just your responsibility to know the code entry points and keep your sections straight with linker commands. -George

hi, 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 > To: > 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. > > Thanks, > > JHlucena > > SW. Engineer > > _____________________________________ > Note: If you do a simple "reply" with your email client, only the > author of this message will receive your answer. You need to do > a "reply all" if you want your answer to be distributed to the > entire group. > > _____________________________________ > About this discussion group: > > To Join: Send an email to > > To Post: Send an email to > > To Leave: Send an email to > > Archives: http://www.yahoogroups.com/group/c54x > > Other Groups: http://www.dsprelated.com > ">http://docs.yahoo.com/info/terms/ ________________________________________________________________________ Delivered using the Free Personal Edition of Mailtraq (www.mailtraq.com)

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. Thanks, JHlucena SW. Engineer