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What could cause a prog(A) call that has worked in previous instances to fail to work properly? This is code I have used in several reflash routines, but in my latest implementation it is writing to memory location 0x00 (although it still seems to successfully erase the flash). Here's a piece of the code: flash_erase: ; Reserve a word on the stack SP += #-1 A = #8555h nop nop nop *SP(0) = #0AAh prog(A) = *SP(0) repeat(#WRITE_DELAY) nop I added the nops to see if there was a pipeline problem, but even with them I am seeing the 0x00AA show up in my IMR register! I can't think of any DSP settings that could cause this, but maybe I'm missing something (I must be, it has worked before). This is on a C5416 processor. Thanks, Brian -- ----------------- Brian C. Lane (W7BCL) Programmer www.shinemicro.com RF, DSP & Microcontroller Design |
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prog(A) not working right?
Started by ●December 2, 2003
Reply by ●December 3, 20032003-12-03
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Brian C. Lane wrote: > > flash_erase: > ; Reserve a word on the stack > SP += #-1 > > A = #8555h > nop > nop > nop > *SP(0) = #0AAh > prog(A) = *SP(0) > > repeat(#WRITE_DELAY) > nop For the record, things like this happen when CPL = 0 and you are trying to use the stack. They also happen because the C54xx is a PITA to debug with its pipeline -- if I had added nops after the *SP(0) and noticed that IMR changed after the attempted stack write, not after the prog(A) I would have caught it sooner. Oh, and the other code ran with interrupts disabled, so even though its a nasty bug, it didn't effect it. Brian -- ----------------- Brian C. Lane (W7BCL) Programmer www.shinemicro.com RF, DSP & Microcontroller Design |
