c6713 access SDRAM

firephenix405

I have a 8MB 32-bit-wide SDRAM linked to ce0 of c6713. Logically, I can only read/write the space from 0x80000000~0x80800000, right? but strangely, I can access the space beyond this range, say ,up 0x81000000, or even 0x8FFFFFFF. I check my configuration on EMIF, and wonder where I computed incorrectly. Thanks!

over 14 years ago

0 RandyP over 14 years ago

TI__Guru* 84110 points

This is probably a mirror image at 0x80800000 of the physical memory at 0x80000000. Write a value to 0x80000000 and see if it shows up at 0x80800000.

Regards,
RandyP

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0 firephenix405 over 14 years ago in reply to RandyP

Prodigy 100 points

I think there is probably an error in mirror image, but I do not know how it happens.

0 RandyP over 14 years ago in reply to firephenix405

TI__Guru* 84110 points

Please explain.

0 firephenix405 over 14 years ago in reply to RandyP

Prodigy 100 points

I am not sure if there is an error. In addition, I wrote a value into the address 0x80800004, and viewed that values at this address indeed changed. Thus I really do not know why it is.

0 RandyP over 14 years ago in reply to firephenix405

TI__Guru* 84110 points

Without information, I cannot help you. I have said the mirror effect is probably what you observe. But this will not affect your project so it can be ignored.

Since you have designed for 8MB and have implemented a system with 8MB, do not make any accesses at or above the address 0x80800000. Ignore this higher range and please continue with your project.

Regards,
RandyP

If you need more help, please reply back. If this answers the question, please click Verify Answer , below.

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c6713 access SDRAM