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I'm working on using McBSP1 on a 5416 in clock stop mode as a SPI master. I have successfully set it up so that it will transmit a block of bytes using DMA #2, and generate an interrupt when the block is finished. Now I'm trying to use 2 DMA channels, one for transmit (to keep the SPI transfer running) and another to receive the bytes. The transmit DMA is triggered by McBSP1 transmit events and receive is triggered by receive events. I have it setup to generate an interrupt when the receive DMA is finished with the required number of bytes. It works the first time (I have it in a loop, watching for one transfer to finish before starting another). But the second time through it outputs bytes but doesn't hit the end of block interrupt. I've checked my McBSP setup and DMA setup and can't find anything obvious. As a simple case I transfer 1 byte (to get a length from the slave) and then start the big transfer. When I just try to run the initial single byte transfer, which uses RX to trigger it with interrupt enabled it will hit the interrupt the first time it runs, but not the second. If I change it to use the TX McBSP event it will work every time. The only change in this case is to set DMSFC2 to 0x6000 (single byte transfer, TX event driven, works) or to 0x5000 (single byte transfer, RX event drive, only works after a reset). Thanks for any help, ideas, etc. Brian ----------------- Brian C. Lane (W7BCL) Programmer www.shinemicro.com RF, DSP & Microcontroller Design |
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McBSP Clock Stop mode
Started by ●December 31, 2002
Reply by ●January 2, 20032003-01-02
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On Tue, 31 Dec 2002 11:51:54 -0800, you wrote: >As a simple case I transfer 1 byte (to get a length from the slave) >and then start the big transfer. When I just try to run the initial >single byte transfer, which uses RX to trigger it with interrupt >enabled it will hit the interrupt the first time it runs, but not the >second. If I change it to use the TX McBSP event it will work every >time. The only change in this case is to set DMSFC2 to 0x6000 (single >byte transfer, TX event driven, works) or to 0x5000 (single byte >transfer, RX event drive, only works after a reset). As usual, answering my own question <G>. I had an old version of the peripheral guide printed out. The PDF version was clear that the McBSP needs to be in reset until the DMA is setup and ready. It works now. Brian ----------------- Brian C. Lane (W7BCL) Programmer www.shinemicro.com RF, DSP & Microcontroller Design |
