STM32 DMA — 直接存储区访问（存储器到存储器）

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#include "main.h"
#include "stm32f1xx.h"
#include "./led/bsp_led.h"

/* 存储器到存储器传输必须使用 DMA1 */
DMA_HandleTypeDef DMA_Handle;

#define DMA_STREAM          DMA1_Channel6
#define DMA_STREAM_CLOCK()  __HAL_RCC_DMA1_CLK_ENABLE();
#define BUFFER_SIZE         32

/* 源数据：常量数组（放在 Flash，DMA 把它读进 SRAM） */
const uint32_t aSRC_Const_Buffer[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};

/* 目标数组：等待被填充 */
uint32_t aDST_Buffer[BUFFER_SIZE];

static void DMA_Config(void);
uint8_t Buffercmp(const uint32_t* pBuffer, uint32_t* pBuffer1, uint16_t BufferLength);

int main(void)
{
  uint8_t TransferStatus;
  SystemClock_Config();
  LED_GPIO_Config();

  DMA_Config();    // 配置并启动 DMA 搬运

  /* 轮询等待 DMA 传输完成标志（TCIF6） */
  while(__HAL_DMA_GET_FLAG(&DMA_Handle, DMA_FLAG_TC6) == RESET)
  {
  }

  /* 比较源与目标是否一致 */
  TransferStatus = Buffercmp(aSRC_Const_Buffer, aDST_Buffer, BUFFER_SIZE);
  if (TransferStatus == 0)
    LED1_ON;       // 不一致 => 失败灯
  else
    LED2_ON;       // 一致 => 成功灯

  while (1);
}

/* DMA 配置：存储器 -> 存储器 */
static void DMA_Config(void)
{
  HAL_StatusTypeDef DMA_status = HAL_ERROR;
  DMA_STREAM_CLOCK();

  DMA_Handle.Instance                 = DMA_STREAM;                 // DMA1_Channel6
  DMA_Handle.Init.Direction          = DMA_MEMORY_TO_MEMORY;        // 存储器到存储器
  DMA_Handle.Init.PeriphInc          = DMA_PINC_ENABLE;             // 外设(源)地址递增
  DMA_Handle.Init.MemInc             = DMA_MINC_ENABLE;             // 内存(目标)地址递增
  DMA_Handle.Init.PeriphDataAlignment= DMA_PDATAALIGN_WORD;         // 源数据 32 位
  DMA_Handle.Init.MemDataAlignment   = DMA_MDATAALIGN_WORD;         // 目标数据 32 位
  DMA_Handle.Init.Mode               = DMA_NORMAL;                 // 普通模式（一次）
  DMA_Handle.Init.Priority           = DMA_PRIORITY_MEDIUM;         // 中等优先级
  HAL_DMA_Init(&DMA_Handle);

  /* 启动传输：源地址 -> 目标地址，共 BUFFER_SIZE 个数据项 */
  DMA_status = HAL_DMA_Start(&DMA_Handle,
                             (uint32_t)aSRC_Const_Buffer,
                             (uint32_t)aDST_Buffer,
                             BUFFER_SIZE);
  if (DMA_status != HAL_OK)
  {
    while (1)   // 启动失败，闪烁报警
    {
      LED1_ON; Delay(0xFFFFFF); LED1_TOGGLE; Delay(0xFFFFFF);
    }
  }
}

/* 比较两个数组是否完全一致 */
uint8_t Buffercmp(const uint32_t* pBuffer, uint32_t* pBuffer1, uint16_t BufferLength)
{
  while(BufferLength--)
  {
    if(*pBuffer != *pBuffer1) return 0;   // 有差异立即返回 0
    pBuffer++;   pBuffer1++;
  }
  return 1;   // 全部相等返回 1
}