TMS320F280049: Issue with SPI synchronization

Hi Jose,

In terms of resetting the SPI and DMA, the general process would be to reset the SPI module and disable, reconfigure and re-enable DMA channel(s). The reset can be done during runtime but needs to be done carefully. 

The PRIORITYSTAT register shows if a transfer is happening and can be used to track what is going on the bus. I would recommend waiting for a channel to not be active before disabling it (or anything else you need it to do). The HALT and RUN bits can be used for this specific application.

Aishwarya

Hello Aishwarya,

This is how we are currently configuring the DMA (once at startup):

    // Initialize DMA
    DMA_initController();
 
    // Configure DMA Ch5 for TX. W
    DMA_stopChannel(DMA_CH5_BASE);
    DMA_clearTriggerFlag(DMA_CH5_BASE);
    DMA_configAddresses(DMA_CH5_BASE, (uint16_t *)(SPIA_BASE + SPI_O_TXBUF),
                        sData);
    DMA_configBurst(DMA_CH5_BASE, BURST, 1, 0);
    DMA_configTransfer(DMA_CH5_BASE, TRANSFER, 1, 0);
    DMA_configMode(DMA_CH5_BASE, DMA_TRIGGER_SPIATX, DMA_CFG_ONESHOT_DISABLE |
                   DMA_CFG_CONTINUOUS_DISABLE | DMA_CFG_SIZE_16BIT);
 
    // Configure DMA Ch5 interrupts
    DMA_enableTrigger(DMA_CH5_BASE);
 
    // Configure DMA Ch6 for RX. 
	DMA_stopChannel(DMA_CH6_BASE);
 
    DMA_clearTriggerFlag(DMA_CH6_BASE);
    DMA_configAddresses(DMA_CH6_BASE, rData,
                        (uint16_t *)(SPIA_BASE + SPI_O_RXBUF));
    DMA_configBurst(DMA_CH6_BASE, BURST, 0, 1);
    DMA_configTransfer(DMA_CH6_BASE, TRANSFER, 0, 1);
    DMA_configMode(DMA_CH6_BASE, DMA_TRIGGER_SPIARX, DMA_CFG_ONESHOT_DISABLE |
                   DMA_CFG_CONTINUOUS_ENABLE | DMA_CFG_SIZE_16BIT);
 
    // Configure DMA Ch6 interrupts
    DMA_setInterruptMode(DMA_CH6_BASE, DMA_INT_AT_END);
    DMA_enableInterrupt(DMA_CH6_BASE);
    DMA_enableTrigger(DMA_CH6_BASE);
 
    
    DMA_startChannel(DMA_CH6_BASE);
    DMA_startChannel(DMA_CH5_BASE)

Do you think we need to re-run this configuration when we need to reset the DMA?

If that's correct we could think of a reset containing the following:

/***************************/
    //Disable and Enable SPI
    SPI_disableModule(SPIA_BASE);
    SPI_enableModule(SPIA_BASE);
/***************************/   
    //Disable DMA Channels
    DMA_stopChannel(DMA_CH6_BASE);
    DMA_stopChannel(DMA_CH5_BASE);
/***************************/ 
    //Wait for DMA to be idle
    //(pseudocode)
    while(PRIORITYSTAT & 0x7 != FALSE); 
/***************************/
    //Reconfigure
    // Initialize DMA
    DMA_initController();
 
    // Configure DMA Ch5 for TX. W
    DMA_clearTriggerFlag(DMA_CH5_BASE);
    DMA_configAddresses(DMA_CH5_BASE, (uint16_t *)(SPIA_BASE + SPI_O_TXBUF),
                        sData);
    DMA_configBurst(DMA_CH5_BASE, BURST, 1, 0);
    DMA_configTransfer(DMA_CH5_BASE, TRANSFER, 1, 0);
    DMA_configMode(DMA_CH5_BASE, DMA_TRIGGER_SPIATX, DMA_CFG_ONESHOT_DISABLE |
                   DMA_CFG_CONTINUOUS_DISABLE | DMA_CFG_SIZE_16BIT);
 
    // Configure DMA Ch5 interrupts
    DMA_enableTrigger(DMA_CH5_BASE);
 
    // Configure DMA Ch6 for RX. 
    DMA_clearTriggerFlag(DMA_CH6_BASE);
    DMA_configAddresses(DMA_CH6_BASE, rData,
                        (uint16_t *)(SPIA_BASE + SPI_O_RXBUF));
    DMA_configBurst(DMA_CH6_BASE, BURST, 0, 1);
    DMA_configTransfer(DMA_CH6_BASE, TRANSFER, 0, 1);
    DMA_configMode(DMA_CH6_BASE, DMA_TRIGGER_SPIARX, DMA_CFG_ONESHOT_DISABLE |
                   DMA_CFG_CONTINUOUS_ENABLE | DMA_CFG_SIZE_16BIT);
 
    // Configure DMA Ch6 interrupts
    DMA_setInterruptMode(DMA_CH6_BASE, DMA_INT_AT_END);
    DMA_enableInterrupt(DMA_CH6_BASE);
    DMA_enableTrigger(DMA_CH6_BASE);
/***************************/
    // Renable
    DMA_startChannel(DMA_CH6_BASE);
    DMA_startChannel(DMA_CH5_BASE);
/***************************/

Can you confirm if this is more or less what we need?

Thanks!

Hi Jose,

This expert is currently on leave until 4/5/24, so please expect a delay in response until then. I will see if I can loop in another expert to assist in the meantime.

Thanks & Regards,

Allison

Hi Jose,

Sorry for the delay. Typically, with a receiving DMA I would recommend stopping the relevant channels during an error condition and re-starting the corresponding channel when the error condition is over so that no errored data is transferred by the DMA at all. Assuming you aren't wanting the DMA to overwrite the previously received data in rData. For your application, is there some indication to the F280049 slave device from the master devices that a reset is occurring? For example, will the CS line go inactive in the middle of a transmission? You could potentially generate an interrupt on this condition and stop the corresponding RX DMA channel in the ISR and then re-start the channel when the condition is no longer present. 

Let me know if this will work for your use case or if I'm misunderstanding what you are trying to achieve.

Best Regards,

Delaney

Hello,

Sorry for the late response, lots of things going on around this parts.  We don't really care about overwriting previously received data in rData, ideally once the transmission is complete that data is copied to another buffer so it can be overwritten safely, if a full message is not received, then it should be discarded too.   We don't have a way to know if the event of a reset on the other processor occurs.  

Is the code sequence above the correct means to "stop the relevant channel and re-start it"?

Thanks!

Hi Jose,

By stopping and starting the relevant channel I meant just calling DMA_stopChannel(); during the error condition and then calling DMA_startChannel(); when the condition is over. However, if you aren't worried about overwriting previously received data, I believe your approach will work. 

Best Regards,

Delaney