"Free Running" DMA Mode on LPC55

rainyorange — Mon, 02 May 2022 15:41:12 GMT

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,

false,

kDMA_AddressInterleave0xWidth,

kDMA_AddressInterleave1xWidth,

);

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

Re: "Free Running" DMA Mode on LPC55

rainyorange — Tue, 03 May 2022 12:52:42 GMT

Solution :

NVIC_SetPriority(PIN_INT0_IRQn, 3);

NVIC_ClearPendingIRQ(PIN_INT0_IRQn);

EnableIRQ(PIN_INT0_IRQn);

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