DMA: Two channels Memory to Memory

In this example, two DMA channels is configured to transfer data in memory-to-memory mode. Using independent buffers to each channel and different data size, the channel 1 will be transfer data of 32 bits and the channel 2 will transfer data of 8 bits.

If you dare, modify the following example to work with interrupts on both transfers, you need to look at the corresponding vector for each channels

#include "bsp.h"
#include <stdio.h>

extern void initialise_monitor_handles(void);

#define BUFFER1_SIZE 32
#define BUFFER2_SIZE 8

/* Handler for DMA1 channel 1 */
DMA_HandleTypeDef DMA1HandlerCh1;

/* Handler for DMA1 channel 2 */
DMA_HandleTypeDef DMA1HandlerCh2;

/* Buffer used as destination of DMA1 Channel 1 with 32 32-bit elements*/
static uint32_t Buffer1[BUFFER1_SIZE];

/* Buffer used as source of DMA1 Channel 1 with 32 32-bit elements*/
static const uint32_t DataSource1[BUFFER1_SIZE] =
{
  0x01020304, 0x05060708, 0x090A0B0C, 0x0D0E0F10,
  0x11121314, 0x15161718, 0x191A1B1C, 0x1D1E1F20,
  0x21222324, 0x25262728, 0x292A2B2C, 0x2D2E2F30,
  0x31323334, 0x35363738, 0x393A3B3C, 0x3D3E3F40,
  0x41424344, 0x45464748, 0x494A4B4C, 0x4D4E4F50,
  0x51525354, 0x55565758, 0x595A5B5C, 0x5D5E5F60,
  0x61626364, 0x65666768, 0x696A6B6C, 0x6D6E6F70,
  0x71727374, 0x75767778, 0x797A7B7C, 0x7D7E7F80
};

/* Buffer used as destination for DMA1 Channel 2 with 8 8-bit elements*/
static uint8_t Buffer2[BUFFER2_SIZE];

/* Buffer used as source of DMA1 Channel 2 with 8 8-bit elements*/
static const uint8_t DataSource2[BUFFER2_SIZE] =
{
  0x11, 0x22, 0x33, 0x44,
  0x55, 0x66, 0x77, 0x88
};

int main( void )
{
    /* Initialize HAL */
    HAL_Init( );

    /* Initialize semihosting */
    initialise_monitor_handles();

    /* Enable DMA 1 clock */
    __HAL_RCC_DMA1_CLK_ENABLE();

    /* Configure DMA 1 Channel 1 */
    DMA1HandlerCh1.Instance                 = DMA1_Channel1;         /* DMA1 Channel 1                                  */
    DMA1HandlerCh1.Init.Request             = DMA_REQUEST_MEM2MEM;   /* Memory to memory transfer request               */
    DMA1HandlerCh1.Init.Direction           = DMA_MEMORY_TO_MEMORY;  /* Data will be transferred from memory to memory  */
    DMA1HandlerCh1.Init.PeriphInc           = DMA_PINC_ENABLE;       /* Increment source address is enabled             */
    DMA1HandlerCh1.Init.MemInc              = DMA_MINC_ENABLE;       /* Increment destination address is enabled        */
    DMA1HandlerCh1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;   /* Source data is 32-bit width                     */
    DMA1HandlerCh1.Init.MemDataAlignment    = DMA_MDATAALIGN_WORD;   /* Destination data is 32-bit width                */
    DMA1HandlerCh1.Init.Mode                = DMA_NORMAL;            /* After finishing last transfer, stop DMA channel */
    DMA1HandlerCh1.Init.Priority            = DMA_PRIORITY_LOW;      /* This DMA channel request config as low priority */
    HAL_DMA_Init( &DMA1HandlerCh1 );

    /* Configure DMA 1 Channel 2 */
    DMA1HandlerCh2.Instance                 = DMA1_Channel2;         /* DMA1 Channel 2                                  */
    DMA1HandlerCh2.Init.Request             = DMA_REQUEST_MEM2MEM;   /* Memory to memory transfer request               */
    DMA1HandlerCh2.Init.Direction           = DMA_MEMORY_TO_MEMORY;  /* Data will be transferred from memory to memory  */
    DMA1HandlerCh2.Init.PeriphInc           = DMA_PINC_ENABLE;       /* Increment source address is enabled             */
    DMA1HandlerCh2.Init.MemInc              = DMA_MINC_ENABLE;       /* Increment destination address is enabled        */
    DMA1HandlerCh2.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;   /* Source data is 8-bit width                      */
    DMA1HandlerCh2.Init.MemDataAlignment    = DMA_MDATAALIGN_BYTE;   /* Destination data is 8-bit width                 */
    DMA1HandlerCh2.Init.Mode                = DMA_NORMAL;            /* After finishing last transfer, stop DMA channel */
    DMA1HandlerCh2.Init.Priority            = DMA_PRIORITY_LOW;      /* This DMA channel request config as low priority */
    HAL_DMA_Init( &DMA1HandlerCh2 );
    
    /* Start DMA1 Channel 1 transfer all elements from Source1 array to destination Buffer1 */
    HAL_DMA_Start( &DMA1HandlerCh1, (uint32_t)&DataSource1, (uint32_t)&Buffer1, BUFFER1_SIZE );

    /* Start DMA1 Channel 2 transfer all elements from Source2 array to destination Buffer2 */
    HAL_DMA_Start( &DMA1HandlerCh2, (uint32_t)&DataSource2, (uint32_t)&Buffer2, BUFFER2_SIZE );

    /* dummy delay to wait for completion */
    HAL_Delay( 500u );

    printf("-------Buffer 1 Content-------------\r\n");
    /* Print Buffer1 elements (transferred using DMA1 Channel 1) */
    for( uint32_t i = 0; i < ( BUFFER1_SIZE / 4u ); i++ )
    {
        printf("%lx %lx %lx %lx\n", Buffer1[i*4], Buffer1[i*4 + 1], Buffer1[i*4 + 2], Buffer1[i*4 + 3] );
    }

    printf("\r\n-------Buffer 2 Content-------------\r\n");
    /* Print Buffer2 elements (transferred using DMA1 Channel 2) */
    for( uint32_t i = 0; i < BUFFER2_SIZE; i++ )
    {
        printf("%x\n", Buffer2[i]);
    }
    
    while(1)
    {
    }

    return 0u;
}