dma.c

Explains how to use the DMA controller.

/*
 * This example shows how to read from ADC Port 0 (the Poti) on CARME-IO2 and
 * and write it to the LEDs on CARME-IO1.
 */

#include <stm32f4xx.h>
#include <carme.h>
#include <carme_io1.h>
#include <carme_io2.h>

#define ADC1_DR_ADDRESS     ((uint32_t) &ADC1->DR)
#define LED_ADDRESS         ((uint32_t) FSMC_CARME_EXTENSION1_BASE + 0x200)

int main(void) {

    ADC_InitTypeDef ADC_InitStruct;
    DMA_InitTypeDef DMA_InitStruct;

    CARME_IO1_Init();
    CARME_IO2_Init();

    /*** Initialize DMA ***/
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
    DMA_Cmd(DMA2_Stream4, DISABLE);
    DMA_DeInit(DMA2_Stream4);  /* Set DMA registers to default values */
    /*
     * Configure the DMA
     * - Source address: ADC1_DR_ADDRESS
     * - Destination address: LED_ADDRESS
     * - Buffer size: 2
     * - Source datasize: 8 bit
     * - Destination datasize: 8 bit
     */
    DMA_InitStruct.DMA_Channel = DMA_Channel_0;
    DMA_InitStruct.DMA_PeripheralBaseAddr = ADC1_DR_ADDRESS;
    DMA_InitStruct.DMA_Memory0BaseAddr = LED_ADDRESS;
    DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStruct.DMA_BufferSize = 2;
    DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Disable;
    DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    DMA_InitStruct.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStruct.DMA_Priority = DMA_Priority_High;
    DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Disable;
    DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA2_Stream4, &DMA_InitStruct);
    DMA_Cmd(DMA2_Stream4, ENABLE);

    /*** Reinitialize ADC ***/
    ADC_Cmd(ADC1, DISABLE);
    ADC_StructInit(&ADC_InitStruct);
    /*
     * Configure the ADC1
     * - Data align: right
     * - Resolution: 8 bit
     * - Continuous conversion: enabled
     * - Nbr of conversions: 2
     */
    ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStruct.ADC_Resolution = ADC_Resolution_8b;
    ADC_InitStruct.ADC_ContinuousConvMode = ENABLE;
    ADC_InitStruct.ADC_ExternalTrigConv = ADC_ExternalTrigConvEdge_None;
    ADC_InitStruct.ADC_NbrOfConversion = 2;
    ADC_InitStruct.ADC_ScanConvMode = ENABLE;
    ADC_Init(ADC1, &ADC_InitStruct);
    ADC_Cmd(ADC1, ENABLE);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_8, 1, ADC_SampleTime_480Cycles);
    ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);

    /*** Enable and start ***/
    ADC_DMACmd(ADC1, ENABLE);       /* Enable ADC1 DMA          */
    ADC_SoftwareStartConv(ADC1);    /* Start ADC1 conversion    */

    for (;;) {
    }
    return 0;
}