RM57L843: SPI DMA Ping Pong Configuration

Hi,

Do I need to disable DMA and then perform the buffer change and then re-enable DMA ? , since I'm changing the control packet configuration.

Regards,

Shantanu S.

Hello Shantanu,

No.

Please see the notes in TRM:

NOTE: Changing the contents of a channel control packet will clear the corresponding pending bit (Section 20.3.1.2) if the channel has a pending status. If the control packet of an active channel (as indicated in Section 20.3.1.3) is changed, then the channel will stop immediately at an arbitration boundary. When the same channel is triggered again, it will begin with the new control packet information.

I'd like to know when or at what condition you switch the DMA destination to other buffer.

Hello,

Currently I'm switching buffer in dmaGroupANotification(), bellow is the attached code.

 g_dmaCTRL stctrl_rx; // control packet object

void dmaGroupANotification(dmaInterrupt_t inttype, uint32 channel)
{

    /*  enter user code between the USER CODE BEGIN and USER CODE END. */
    /* USER CODE BEGIN (8) */
    if(inttype == LFS){
        if(channel == DMA_CH0){
            ucRxThrDMAflag_g=1; // flag to indicate dma interrupt for processing of buffers
            if( ePING_BUFF == ELastUsedBuff )
            {
                stctrl_rx.DADD = (uint32_t)&stDCDCDMAMeas_g.uiDMARxPong; /* switch to pong buff */
                ELastUsedBuff = ePONG_BUFF;
                EBuffToProcess = ePING_BUFF;
                dmaSetCtrlPacket(DMA_CH1, stDCDCDMAMeas_g.stctrl_rx);
                cycles_PMU_code = 1;
                gioSetBit(hetPORT1, BIT23, 1);//tp 28
            }
            else
            {
                stctrl_rx.DADD = (uint32_t)&stDCDCDMAMeas_g.uiDMARxPing; /* switch to ping buff */
                ELastUsedBuff = ePING_BUFF;
                EBuffToProcess = ePONG_BUFF;
                dmaSetCtrlPacket(DMA_CH1, stctrl_rx);
                
            }

            /* trigger dma  */
            dmaSetChEnable(DMA_CH0, DMA_HW);
            dmaSetChEnable(DMA_CH1, DMA_HW);
            spiREG1->GCR1   |= (1U << 24UL);
            spiREG1->INT0   |= (1U << 16UL);
        }
    }
}

I have initialize the control packet object in my initialization, below is the code for it;

stctrl_rx.DADD = (uint32_t)&stDCDCDMAMeas_g.uiDMARxPing; /* initialize rx destination to ping buff */
ELastUsedBuff = ePING_BUFF;

stctrl_rx.SADD        = (uint32_t)&(spiREG1->BUF);
stctrl_rx.CHCTRL      = 0;
stctrl_rx.FRCNT       = COUNT;
stctrl_rx.ELCNT       = 1;
stctrl_rx.ELDOFFSET   = 0;                /* element destination offset */
stctrl_rx.ELSOFFSET   = 0;                /* element destination offset */
stctrl_rx.FRDOFFSET   = 0;                /* frame destination offset   */
stctrl_rx.FRSOFFSET   = 0;                /* frame destination offset   */
stctrl_rx.PORTASGN    = PORTB_READ_PORTA_WRITE;
stctrl_rx.RDSIZE      = ACCESS_16_BIT;
stctrl_rx.WRSIZE      = ACCESS_16_BIT;
stctrl_rx.TTYPE       = FRAME_TRANSFER;   /* transfer type              */
stctrl_rx.ADDMODERD   = ADDR_FIXED;       /* address mode read          */
stctrl_rx.ADDMODEWR   = ADDR_INC1;        /* address mode write         */
stctrl_rx.AUTOINIT    = AUTOINIT_OFF;     /* autoinit                   */

    dmaSetCtrlPacket(DMA_CH0, stDCDCDMAMeas_g.stctrl_tx);
    dmaSetCtrlPacket(DMA_CH1, stDCDCDMAMeas_g.stctrl_rx);
    dmaEnableInterrupt(DMA_CH0, LFS, DMA_INTA);
    dmaEnableInterrupt(DMA_CH1, LFS, DMA_INTA);
    dmaEnable();  //enable dma

I hope this is sufficient and I'm doing it the right way.

Let me know if you want to know any other details.

Regards,

Shantanu S.

Please try your code. if any issue, let me know.