Problem on the data transferring using EDMA with DSP/BIOS

beaver

I have studied the example provided in the "C:\Program Files\Texas Instruments\edma3_lld_01_10_00_01\examples\edma3_driver\evm6474_0\". It is about the data transferring using EDMA (low level driver) with DSP/BIOS on C6474 EVM. The example works well when the source buffer and destination buffer are all in the external memory (default setting). However, when I changed the destination buffer to the L2 memory, the data transferring does not work any more. Any further setting is needed to make it work for data transferring between the external mem and L2 mem?

over 15 years ago

0 sergey manuhin over 15 years ago

Intellectual 710 points

Are you sure, that your buffer is in L2? Can you write any data to the destination buffer? How can you place your buffer in L2.

0 beaver over 15 years ago in reply to sergey manuhin

Intellectual 575 points

Yes. I made some modifications based on the example. I create a section in the "L2RAM" and allocate the Destination buffer in this section and I have checked the address of this buffer, it stars from 0x 00800000, so it is in L2 memory. However, after I made these modification, the DMA does not work, the data can not be transferred to the destination buffer in L2.

0 sergey manuhin over 15 years ago in reply to beaver

Intellectual 710 points

Try to disable L2 cash. May be when you fill array in DDR2, really you data are only in the cache L2. When you copy data from DDR2 by EDMA you copy real data from DDR2, however your data are in the cache.

Try to copy data from L2 to DDR2.

0 JayR over 15 years ago in reply to sergey manuhin

TI__Prodigy 230 points

Are you programming the EDMA with the local (private) address to the memory (0x00800000)? The EDMA must use the global address (0x10800000 for core 0) to access the memory.

0 beaver over 15 years ago in reply to JayR

Intellectual 575 points

Thank you so much!!!! The problem is the private address. After I used the global address, the EDMA works.

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Problem on the data transferring using EDMA with DSP/BIOS