DMA triggering via Timer(Input capture mode)

Pooya Alirezaei · ‎2017-11-04

Posted on November 04, 2017 at 11:17

I want to transfer some data between two microcontrollers via 16 lines of data and one clk line.

(Based on STM Application note AN4666 ''Parallel synchronous transmition using GPIO and DMA'').

I use two STM32f407 for this Application.

In transmitter side micro puts 16 bits of data on port when clk line goes high(Rising edge).

In receiver side I want to read 16 bits of data from Port when clk line goes high and put them

into Tx_Buff array via DMA.

I want when the rising edge of clk has been detected by Timer8-CH4(PC.9) -which configured in input capture mode-

it acts as DMA trigger for transmitting the 16 bits data to TX_Buff.

Finally I expect DMA Interrupt occurs when 750 transfers completed.

While testing, the Transmitter side works fine (clk and data) and I monitored them in Logic analayzer and the Timer works fine too, but the problem is DMA not triggering (I'm sure of it because I check the registers) so as follow, no interrupt occurs in receiver side.

This is my code.

Do you have any idea?

void Receiver_Config(void)

{

GPIO_InitTypeDef gpioClk;

GPIO_InitTypeDef gpioData;

TIM_ICInitTypeDef icTIM;

DMA_InitTypeDef dma;

NVIC_InitTypeDef nvic;

/* CLK - GPIO (PC.9) */

/* ************************************************************************************************************* */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC , ENABLE);

gpioClk.GPIO_Mode = GPIO_Mode_AF;

gpioClk.GPIO_OType = GPIO_OType_OD;

gpioClk.GPIO_Pin = GPIO_Pin_9;

gpioClk.GPIO_PuPd = GPIO_PuPd_NOPULL;

gpioClk.GPIO_Speed = GPIO_High_Speed;

GPIO_Init(GPIOC , &gpioClk);

GPIO_PinAFConfig(GPIOC , GPIO_PinSource9 , STU_CLK_GPIO_AF);

/* ************************************************************************************************************* */

/* Data - GPIO (PORT_E) */

/* ************************************************************************************************************* */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE , ENABLE);

gpioData.GPIO_Mode = GPIO_Mode_IN;

gpioData.GPIO_OType = GPIO_OType_OD;

gpioData.GPIO_PuPd = GPIO_PuPd_DOWN;

gpioData.GPIO_Speed = GPIO_High_Speed;

GPIO_Init(GPIOE , &gpioData);

/* ************************************************************************************************************* */

/* CLK - Timer */

/* ************************************************************************************************************* */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8 , ENABLE);

icTIM.TIM_Channel = TIM_Channel_4;

icTIM.TIM_ICPolarity = TIM_ICPolarity_Rising;

icTIM.TIM_ICSelection = TIM_ICSelection_DirectTI;

icTIM.TIM_ICPrescaler = TIM_ICPSC_DIV1;

icTIM.TIM_ICFilter = 0;

TIM_ICInit(TIM8 , &icTIM);

TIM_SelectOutputTrigger(TIM8 , TIM_TRGOSource_Reset);

TIM_DMAConfig(TIM8 , TIM_DMABase_CR1 , TIM_DMABurstLength_1Transfer);

TIM_SelectCCDMA(TIM8 , ENABLE);

TIM_DMACmd(TIM8 , TIM_DMA_Trigger , ENABLE);

/* ************************************************************************************************************* */

/* DMA : DMA2 Stream1 Channel7 */

/* ************************************************************************************************************* */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 , ENABLE);

dma.DMA_BufferSize = 750;

dma.DMA_Channel = DMA_Channel_7;

dma.DMA_DIR = DMA_DIR_PeripheralToMemory;

dma.DMA_FIFOMode = DMA_FIFOMode_Disable;

dma.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;

dma.DMA_Memory0BaseAddr = (uint32_t)&(Tx_Buff[0][0]);

dma.DMA_MemoryBurst = DMA_MemoryBurst_Single;

dma.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

dma.DMA_MemoryInc = DMA_MemoryInc_Enable;

dma.DMA_Mode = DMA_Mode_Normal;

dma.DMA_PeripheralBaseAddr = 0x40021014; /* GPIOE_ODR : GPIOE Output Data Register */

dma.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

dma.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;

dma.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

dma.DMA_Priority = DMA_Priority_VeryHigh;

DMA_Init(DMA2_Stream1 , &dma);

DMA_ITConfig(DMA2_Stream1 , DMA_IT_TC , ENABLE);

DMA_Cmd(DMA2_Stream1 , 750);

/* ************************************************************************************************************* */

/* DMA - Interrupt */

/* ************************************************************************************************************* */

nvic.NVIC_IRQChannel = DMA2_Stream1_IRQn;

nvic.NVIC_IRQChannelCmd = ENABLE;

nvic.NVIC_IRQChannelPreemptionPriority = 0;

nvic.NVIC_IRQChannelSubPriority = 0;

NVIC_Init(&nvic);

/* ************************************************************************************************************* */

}

void main(void)

{

// Initialization

Receiver_Config();

while(1);

}

void DMA2_Stream1_IRQHandler(void)

{

// TODO : Clear IT pending flags & etc

}

Looking forward hearing from you.

Best Regards.

Tesla DeLorean · ‎2017-11-04

Posted on November 04, 2017 at 14:07

>>

Do you have any idea?

You want to trigger using TIM8_CC4, not TIM8_UP

Per Reference Manual that would be DMA2 Stream7 Channel7

dma.DMA_PeripheralBaseAddr

= (uint32_t)&GPIOE->IDR; // Input Address

Assuming PC9 is correct..

Set up timer properly

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE); /* TIM8 clock enable */

TIM_ICInitStructure.TIM_Channel = TIM_Channel_4; // TIM8_CC4

TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;

TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;

TIM_ICInitStructure.TIM_ICFilter = 0x0;

TIM_ICInit(TIM8, &TIM_ICInitStructure);

TIM_CtrlPWMOutputs(TIM8, ENABLE); /* TIM Main Inputs/Output Enable */

TIM_Cmd(TIM8, ENABLE); /* TIM enable counter */

TIM_DMACmd(TIM8, TIM_DMA_CC4, ENABLE); /* Enable TIM8_CC4 DMA Requests */

Don't enable interrupt until the service routine is done

F4 GPIO+DMA+TIM External Trigger Example

https://community.st.com/thread/22634#comment-54386

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