DMA

Introduction

The MikroSDK.Driver.DMA library provides a high-level interface for configuring and controlling Direct Memory Access (DMA) modules on microcontrollers.

This library simplifies the process of setting up DMA transfers between memory and peripherals, enabling efficient data movement without CPU intervention.

DMA is a feature of microcontrollers that allows for the transfer of data directly between memory and peripherals, or between memory regions, without CPU involvement. This library abstracts the complexity of configuring and controlling DMA transfers, making it easier to leverage this powerful feature in your applications.

API Name

• MikroSDK.Driver.DMA

API Files

• GitHub Repository:

  • Header file
  • Source file
  • Configuration (CMake) file

Prerequisites

• Library Manager:

  • Select Driver.DMA to add the API to your project using the Library Manager in NECTO Studio.

• Headers:

  • Include the Driver.DMA header in your source files to access the DMA functions.
  • This header pops up in the lower right part of NECTO Studio once you perform the previous task (while selecting Driver.DMA in Library Manager)
  • Alternatively, include the drv_dma.h header in your source files to access the DMA functions.

• CMakeLists:

  • You do not have to perform anything, configuration (CMake) file is already taken care of automatically while you performed the first task in this Prerequisites!
  • You can ensure that your CMakeLists.txt includes the necessary configurations to link against the MikroSDK.Driver.DMA library.

Code Examples

• How to properly test DMA?

/* Project name:
 *  DMA Memory to Memory demo
 * Copyright:
 *  (c) MIKROE, 2024.
 * Description:
 *  Example is meant for demonstrating DMA Memory to Memory functionality
 *  using mikroSDK 2.0. If the DMA transfer was successful, assigned LED
 *  will be blinking.
 */

// ------------------------------------------------------------------ INCLUDES
/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "drv_digital_out.h"
#include "drv_dma.h"
#include "board.h"
#include "delays.h"

// -------------------------------------------------------------------- MACROS
#ifndef PB0
#define TEST_PIN_NAME HAL_PIN_NC // TODO PB0 tested on TIVA, PIC32, PIC18 and STM32
#else
#define TEST_PIN_NAME PB0
#endif

#define BUFFER_SIZE 32

#if defined(PIC18F57Q43)       || defined(PIC18F57K42) || \
    defined(PIC32MZ2048EFH144) || defined(PIC32MX795F512L) || \
    defined(GD32VF103VBT6)
    #define TEST_DMA_MODULE 0
    #define TEST_DMA_STREAM 0
    #define TEST_DMA_CHANNEL 0
#elif defined(TM4C129XNCZAD)
    #define TEST_DMA_MODULE 0
    #define TEST_DMA_STREAM 30
    #define TEST_DMA_CHANNEL 0
#elif defined(STM32F407ZG)
    #define TEST_DMA_MODULE 1
    #define TEST_DMA_STREAM 3
    #define TEST_DMA_CHANNEL 3
#elif defined(MK64FN1M0VDC12)
    #define TEST_DMA_MODULE 0
    #define TEST_DMA_STREAM 0
    #define TEST_DMA_CHANNEL 60
#else
    #define TEST_DMA_MODULE "provide the MCU appropriate module number"
    #define TEST_DMA_STREAM "provide the MCU appropriate steam number"
    #define TEST_DMA_CHANNEL "provide the MCU appropriate channel number"
#endif

// ----------------------------------------------------------------- VARIABLES
static dma_config_t dma_cfg;
static dma_t dma;
static dma_channel_t channels;

static digital_out_t pin;

int check_result = 0xFF;
static const uint32_t buffer_src_flash[ BUFFER_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
};

static uint32_t buffer_dst_ram[ BUFFER_SIZE ];

// ----------------------------------------------------------------- USER CODE

int main(void)
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    digital_out_init( &pin, TEST_PIN_NAME );
    digital_out_low( &pin );

    //------------------------------------------------------------------------
    // DMA settings
    //------------------------------------------------------------------------

    // Set default configuration values first
    dma_configure_default( &dma_cfg );

    // Set data alignment to 1 byte
    dma_cfg.data_align_source = DMA_DATA_ALIGN_BYTES_1;
    dma_cfg.data_align_destination = DMA_DATA_ALIGN_BYTES_1;

    // Set memory addresses to be incremented for both source and destination
    dma_cfg.src_inc = true;
    dma_cfg.dst_inc = true;

    // Check if the desired DMA channel is free
    dma_get_channels( &channels );
    if ( !channels[ TEST_DMA_MODULE ][ TEST_DMA_STREAM ][ TEST_DMA_CHANNEL ] ) {
        dma_cfg.module = TEST_DMA_MODULE;
        dma_cfg.stream = TEST_DMA_STREAM;
        dma_cfg.channel = TEST_DMA_CHANNEL;
    } else {
        // Handle error
    }

    // Initialize the DMA HW
    if ( DMA_SUCCESS != dma_open( &dma, &dma_cfg ) ) {
        // Handle error
    }

    // Set priority to very high
    if ( DMA_SUCCESS != dma_set_priority( &dma, DMA_PRIORITY_VERY_HIGH ) ) {
        // Handle error
    }

    // Set the DMA transfer direction to memory to memory
    if ( DMA_SUCCESS != dma_set_direction( &dma, DMA_DIRECTION_MEMORY_TO_MEMORY ) ) {
        // Handle error
    }

    // Set the DMA transfer mode to normal
    if ( DMA_SUCCESS != dma_set_mode( &dma, DMA_MODE_NORMAL ) ) {
        // Handle error
    }

    // Configure the DMA transfer source and destination addresses,
    // as well as its size
    if ( DMA_SUCCESS != dma_set_transfer_config(
                            &dma,
                            (uint32_t)&buffer_src_flash,
                            (uint32_t)&buffer_dst_ram,
                            sizeof( buffer_src_flash ),
                            DMA_SOURCE_MEMORY_REGION_PFM
                        ) ) {
        // Handle error
    }

    //------------------------------------------------------------------------
    // EOF DMA settings
    //------------------------------------------------------------------------

    // Start transmission
    if ( DMA_SUCCESS != dma_transfer_start( &dma ) ) {
        // Handle error
    }

    // Disable the transfer when it is completed
    dma_transfer_stop( &dma );

    // Check if transfer was completed successfully
    check_result = memcmp( buffer_src_flash,
                           buffer_dst_ram,
                           sizeof( buffer_src_flash ) );

    // Deinitilize the DMA HW
    dma_close( &dma );

    // Blink if the DMA transfer was completed successfully
    if ( !check_result ) {
        while( 1 ) {
            digital_out_toggle( &pin );
            Delay_100ms();
        }
    }

    return 0;
}

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