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Blackfin SPORT 8 bit communication without DMA

Question asked by Nch on Aug 18, 2009
Latest reply on Aug 19, 2009 by Nch

Hi,All,

   I'm designing BF548+BF534 structure, and use SPORT for intra communication between BF548 and BF534. Both have the same SCLK and SPORT CLK value. And transmitter use internal Frame Sync and Clock signal,while receiver use external Frame Sync and Clock signal.

   I just use code like:

    while ((*pSPORT1_STAT & RXNE)==0);
          return *pSPORT1_RX;

to transmit and receive data.

 

I found that if I set SPORTs as

     *pSPORT1_TCR2    = 16; //or any 16<=length<=31
     *pSPORT1_TFSDIV  = 31;

........................

 

    *pSPORT1_RCR2    = 16; //or any 16<=length<=31
    *pSPORT1_RFSDIV  = 31;

 

There's correct Frame Sync, Clock and data.

 

If I set SPORTs as

     *pSPORT1_TCR2    = 15; //or any 2<=length<=15
     *pSPORT1_TFSDIV  = 31;

........................

 

    *pSPORT1_RCR2    = 15; //or any 2<=length<=15
    *pSPORT1_RFSDIV  = 31;


or

      *pSPORT1_TCR2    = 7; 
     *pSPORT1_TFSDIV  = 7;

........................

 

    *pSPORT1_RCR2    = 7;
    *pSPORT1_RFSDIV  =7;

 

There's no Frame Sync, and no data transmitted, but there's correct clock signal.

 

Actually I need 8 bit SPORT communication without DMA.

 

According to <ADSP-BF537 Blackfin Processor Hardware Reference>, P12-22, "setting SLEN to 7 does not produce a frame sync pulse on each byte
transmitted."  What does it mean?

 

Thanks.

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