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Different results from EDMA (reposted from DaVinci 64 forum)

Anonymous
Anonymous

Hi,

 

I would like to ask a question on EDMA on DM6437. (This question is also posted in DaVinci 64x forum)

 

TI Wiki page Programming EDMA without EDMA3LLD package gave an example of configuring EDMA in the "hard manner" by modifying registers directly and I adapted the code into my DM6437 program:

 

Example code:

 

 

In my code,

 

 

However, when executing these code turns out to have no effect, and the content of srcBuff  was not copied into dstBuff at all.

 

I have triple-checked register address and all of them are correct.

 

If instead of copying to dstBuff, I configure DMA destination to a fixed memory location, say, 0x82000000, then sometimes 0x8E would be copied to the destination array, but only for the first 4 entries; the remaining 512-4=508 entries remain unchanged. (1 )Changing 0x8E to other value, or (2) Changing destination to other fixed location, say, 0x83000000, resulted in the same that only first 4 out of 512 bytes are copied.

 

 

I would like to ask about:

1.    Why for fixed location destination only 4 bytes are copied?

2.    Why no copy occur when destination is set to dstBuff?

3.    Did I miss any initialization register? Since I copied the Wiki example line for line, if I missed any register(s), does it mean the Wiki article also missed the same register(s)?

 

 

 

Thanks,

Zheng