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Question to Haixiao: about TMS570LS3137 MIBSPI & DMA application

Yanzhong Li
Intellectual 470 points

Haixiao or other experts,

In the earlier thread, Haixiao helped me resolved the MibSPI and DMA setting issue. (see below link)

RE: To Haixiao - TMS570LS3137 MIBSPI and DMA configuration issue

Here come the further questions based on above MibSPI and DMA setting.

I initialized the DMA channel transfer frames (each frame has one element) from MibSPI TG0 RX (ie. sourse addr) to RAM data array (i.e. destination addr).

MibSPI TG0 is triggered by external trigger signal. Each trigger let MibSPI TG0 received one data, and DMA transfers it to RAM.

I set the DMA channel is triggered by Hardware Request for each frame.   (I can not use Block transfer mode in this case)

If I set the frame count = 1000, I can get 1000 data at the data array in RAM.

Now, I want a "Ping-pong" style data buffer. In other words, I will have two set of data array. Let's say Bank1 and Bank2.

I planed was to using DMA LFS interruption, in the ISR of Bank1 LFS interruption (after get 999 data to Bank1), the DMA channel Destiniation address will be changed from Bank1 to Bank2.  next time will switch to Bank1 again, and so on.

My question: after the 1000 frames to BANK1 was transfered after the system initialization,  how can I re-set the DMA to start the following 1000 frames to BANK2?

(It seems all settings still be effective there. My external triggers also available, but the DMA stops because the initialization 1000 frams transfer has been complete.)

This should be implemented in the DMA interruption ISR so that I can keep getting data as long as the external triggers available.

I realized there is "Auto-Initiation" feature, but it's for block transfer, won't work for my case.

 

Thanks in advance,

Yanzhong

  

 

  • 0
    TI__Genius 13810 points

    I discussed your question with Zhaohong.

    The Auto-Initation works no matter it is a frame trigger or a block trigger. So, in your code,

    One frame has one element,

    One block has 2000 frames,

    each SPI transfer triggers one frames,

    enable the autoinit,

    Set up the half block complete and block complete interrupt to indicate the switching between buffer A (1st 1000 data) and buffer B(2nd 1000 data).

    I will be in vacation for the coming three weeks. If this post does not solve your problem, please start with another thread because I don't have internet access during vactation.

    Best Regards,

    Haixiao

  • 0 in reply to Haixiao Weng
    Intellectual 470 points

    Haixiao,

    Thanks for the reply. I might misunderstand the meaning of the "Block" here.

    I will follow the suggestion to try.

    Have a good vacation!

    Yanzhong