"Free Running" DMA Mode on LPC55

[rainyorange]

Hi,

I'm currently working on a project that require DMA to be hardware triggered each time there is a rising edge generated by a clock on a GPIO pin.

For now I've managed to get the DMA working properly in "one shot mode" but I can't figure out how to configure the DMA to be triggered not once but each time there is a rising edge.

I think there in a bit to reset somewhere but I have no clue.

Here is the code :

volatile bool g_Transfer_Done = false;

dma_handle_t g_DMA_Handle;

static const int BUFF_LENGTH = 4U;

uint32_t dta = 0xAABBCCDD;

/* DMA descripter table used for ping-pong mode. */

SDK_ALIGN(uint32_t s_dma_table[2 * sizeof(dma_descriptor_t)], FSL_FEATURE_DMA_DESCRIPTOR_ALIGN_SIZE) = {0};

int cpt = 0;

void DMA_Callback(dma_handle_t *handle, void *param, bool transferDone, uint32_t tcds)

{

    if (transferDone)

    {

        cpt++;

    }

}

   

void DMA_Initialisation()

    {

        uint32_t xferConfig = DMA_CHANNEL_XFER(true,

                                               true,

                                               true,

                                              false,

                                                  4,

                      kDMA_AddressInterleave0xWidth,

                      kDMA_AddressInterleave1xWidth,

                                                  4

        );

        DMA_Init(DMA0);

        DMA_CreateHandle(&g_DMA_Handle, DMA0, 0);

        DMA_EnableChannel(DMA0, 0);

        DMA_SetCallback(&g_DMA_Handle, DMA_Callback, NULL);

        DMA_SetChannelConfig(DMA0, 0, &triggerConfig, false);

        PINT_Init(PINT);

        INPUTMUX_Init(INPUTMUX);

        INPUTMUX_AttachSignal(INPUTMUX, kPINT_PinInt0, kINPUTMUX_GpioPort1Pin28ToPintsel);

        INPUTMUX_AttachSignal(INPUTMUX, kPINT_PinInt0, kINPUTMUX_PinInt0ToDma0);

        INPUTMUX_Deinit(INPUTMUX); /* Turnoff clock to inputmux to save power. Clock is only needed to make changes */

        /* Clear Rise and Fall flags first */

        PINT->RISE = (1UL << kPINT_PinInt0);

        PINT->FALL = (1UL << kPINT_PinInt0);

        /* select level or edge sensitive */

        PINT->ISEL = (PINT->ISEL & ~(1UL << kPINT_PinInt0)) |

                    (((PINT_PIN_RISE_EDGE & PINT_PIN_INT_LEVEL) != 0U) ? (1UL << kPINT_PinInt0) : 0U);

        /* enable rising edge */    

        PINT->SIENR = 1UL << kPINT_PinInt0;

        //(void *)(&GPIO->PIN[1])

        DMA_PrepareChannelTransfer(&transferConfig,

                                              &dta,

                                    &destBuffer[0],

                                        xferConfig,

                               kDMA_MemoryToMemory,

                                    &triggerConfig,

             (dma_descriptor_t *)&(s_dma_table[0])

        );

        triggerConfig.type  = kDMA_RisingEdgeTrigger;

        triggerConfig.burst = kDMA_LevelBurstTransfer;

        triggerConfig.wrap  = kDMA_NoWrap;

        DMA_SubmitChannelTransfer(&g_DMA_Handle, &transferConfig);

        /* Set two DMA descripters to use ping-pong mode. */

        DMA_SetupDescriptor((dma_descriptor_t *)&(s_dma_table[0]), xferConfig, &dta,

                            (void *)destBuffer, (dma_descriptor_t *)&(s_dma_table[4]));

        DMA_SetupDescriptor((dma_descriptor_t *)&(s_dma_table[4]), xferConfig, &dta,

                            (void *)destBuffer, (dma_descriptor_t *)&(s_dma_table[0]));

        DMA_StartTransfer(&g_DMA_Handle);

    }

Note : I'm using a LPC55

Thank's for your attention 

[rainyorange · Accepted solution]

Solution :

        NVIC_SetPriority(PIN_INT0_IRQn, 3);

        NVIC_ClearPendingIRQ(PIN_INT0_IRQn);

        EnableIRQ(PIN_INT0_IRQn);