Newbiew q about McBSP and DMA | TMS320C55x

Technical discussions about the TI C55x DSPs (including the c5501, c5502, c5503, c5507, c5509, c5510 and OMAP5910).

Hi all, I pretty new to C55x, so please bare with me... I've read the "TMS320C55x DSP Peripherials Reference Guide", the chapters dealing with DMa and McBSP. I've reviewed the examples that came with the C5510 DSK. What I'm trying to do? Write a driver that reads a word (16bit), which is a len of the comming buffer and then read 'len' number of words (16bit). The reading is from the McBSP, through DMA, to the DARAM. After The buffer is stored in memory, I need to process it (by a 3rd party algorithm) and write back the result, knowing its length in advance. The result overides the input to the algorithm. The destination buffer can be allocated before starting the operation; The max length is 450bytes=225words. I have some ideas on how to implement that, but I think it can be done 'cleaner'... (I thought of an McBSP receive ISR that reads the length, set the DMA to the correct number of words to read and enables it; An DMA receive ISR to signal the completion of reception and... well the trasmit part is differnt isn't it? I need to set the DMA and McBSP, enable both and write the first word to the McBSP 'manualy'... Makes sens?) Now, the questions: 1. Do I need an ISR for the McBSP? Maybe only for the tx part? 2. Do I need an ISR for the DMA? Again, maybe only for the tx part? 3. I tried to set the number of elements in a frame of the receive McBSP to 225 but the max is 128... How can I set to the McBSP and the DAM to read an arbitary number of elements? 4. Do I need 2 DMA channels with 2 differnt configurations? 5. Should I use DMA's end-of-block interrupt or end-of-frame? Please, help clear the 'fog' here... Thank you for your time David

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Discussion Groups | TMS320C55x | Newbiew q about McBSP and DMA

Newbiew q about McBSP and DMA - davidganor - Mar 30 11:31:00 2003