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Problem of McASP on OMAP-L137/C6747

Zuofei Wang
Prodigy 145 points
Other Parts Discussed in Thread: OMAP-L137

Hi. I'm writing a program which will do a loopback test of codec AIC3106 on OMAP-L137 EVM. I use EDMA to receive data from McASP to the memory and then play back. At first I disabled the McASP transmitting event(AXEVT) in EDMA but made AREVT enabled. Then I started the McASP's clock. The receiving is OK, I can see EDMA tranferring data from McASP to memory. After all the data are transferred, I tried to play back through EDMA by enabling AXEVT. But this step was not working. 

If I enabled AXEVT before McASP's clock was running. The transmission is working, but EDMA will transfer data to McASP before when I want it to.

I'm using the synchronous transmit/receive operation in McASP. (ACLKXCTL.ASYNC=0) I tried to use asynchronous mode, but I cannot receive data in this mode.

How can I control the start and stop of EDMA transmission with McASP's clock running?

  • 0
    TI__Guru 62975 points

    Zuofei,

    I just noticed that this is a fairly old topic with no replies.  Are you still experiencing problems?

    -Tommy

  • 0 in reply to tlee
    Prodigy 145 points

    Hello Tommy,

    I've fixed this problem. Besides setting the Event Enable Set Register(EESR), the state machine of McASP has to be reset (by setting XGBLCTL of McASP) in order to start transmission.

    Thanks anyway.

    --Zuofei

     

  • 0
    Prodigy 250 points

    hello zuofei,

    I'm working on L137 also, I could get data from MCASP by CPU, but for EDMA, it seems the src address was not correct so I could not get the data in RBUF(RBUF11, the offset is 2ACh) I'm sure I have already received the Event, but the read operation could only start one time and the data read out is not the one in the Rbuf11(the data the dma got is always b0h) could you please give me some advise?

  • 0 in reply to Chuangwang
    Prodigy 145 points

    Hi Chuangwang,

    If you are using EDMA, the src address should be the address of McASP port. (0x01D06000 for McASP1, refer to the OMAP-L137 Manual).

    --

    Zuofei