DMA存儲器到存儲器傳輸代碼講解

M to M:Flash to Sram,把內部flash的數據傳輸到內部SRAM(DRAM主要存放的是變量, flash 主要存放代碼)

M to P: SRAM to 串口,同時LED閃爍,演示DMA傳送數據不需要占用CPU

bsp_dma_mtm.h

#ifndef __BSP_DMA_MTM_H
#define __BSP_DMA_MTM_H

#include "stm32f10x.h"

// 要發送的數據大小
#define BUFFER_SIZE     32

#define  MTM_DMA_CLK       RCC_AHBPeriph_DMA1
#define  MTM_DMA_CHANNEL   DMA1_Channel6
#define  MTM_DMA_FLAG_TC   DMA1_FLAG_TC6

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

#endif  /* __BSP_DMA_MTM_H */

bsp_dma_mtm.c

#include "bsp_dma_mtm.h"


/* 定義aSRC_Const_Buffer數組作為DMA傳輸數據源
 * const關鍵字將aSRC_Const_Buffer數組變量定義為常量類型
 * 表示數據存儲在內部的FLASH中
 */
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};
/* 定義DMA傳輸目標存儲器
 * 存儲在內部的SRAM中
 */
uint32_t aDST_Buffer[BUFFER_SIZE];

//typedef struct
//{
//  uint32_t DMA_PeripheralBaseAddr;   // 外設地址
//  uint32_t DMA_MemoryBaseAddr;       // 存儲器地址
//  uint32_t DMA_DIR;                  // 傳輸方向
//  uint32_t DMA_BufferSize;           // 傳輸數目
//  uint32_t DMA_PeripheralInc;        // 外設地址增量模式
//  uint32_t DMA_MemoryInc;            // 存儲器地址增量模式
//  uint32_t DMA_PeripheralDataSize;   // 外設數據寬度
//  uint32_t DMA_MemoryDataSize;       // 存儲器數據寬度
//  uint32_t DMA_Mode;                 // 模式選擇
//  uint32_t DMA_Priority;             // 通道優先級
//  uint32_t DMA_M2M;                  // 存儲器到存儲器模式
//}DMA_InitTypeDef;

void MtM_DMA_Config(void)
{
	DMA_InitTypeDef DMA_InitStruct;

	RCC_AHBPeriphClockCmd(MTM_DMA_CLK, ENABLE);

	DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)aSRC_Const_Buffer;
	DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)aDST_Buffer;
	DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralSRC;

	DMA_InitStruct.DMA_BufferSize = BUFFER_SIZE;

	DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Enable;
	DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
	DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
	DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;

	DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;
	DMA_InitStruct.DMA_Priority = DMA_Priority_High;
	DMA_InitStruct.DMA_M2M = DMA_M2M_Enable;

	DMA_Init(MTM_DMA_CHANNEL, &DMA_InitStruct);

	DMA_ClearFlag(MTM_DMA_FLAG_TC);
	DMA_Cmd(MTM_DMA_CHANNEL, ENABLE);
}

/**
  * 判斷指定長度的兩個數據源是否完全相等，
  * 如果完全相等返回1，只要其中一對數據不相等返回0
  */
uint8_t Buffercmp(const uint32_t* pBuffer,
                  uint32_t* pBuffer1, uint16_t BufferLength)
{
  /* 數據長度遞減 */
  while(BufferLength--)
  {
    /* 判斷兩個數據源是否對應相等 */
    if(*pBuffer != *pBuffer1)
    {
      /* 對應數據源不相等馬上退出函數，並返回0 */
      return 0;
    }
    /* 遞增兩個數據源的地址指針 */
    pBuffer++;
    pBuffer1++;
  }
  /* 完成判斷並且對應數據相對 */
  return 1;
}

main.c

#include "stm32f10x.h"
#include "bsp_led.h"
#include "bsp_dma_mtm.h"

extern const uint32_t aSRC_Const_Buffer[BUFFER_SIZE];
extern uint32_t aDST_Buffer[BUFFER_SIZE];

#define SOFT_DELAY Delay(0x0FFFFF);

void Delay(__IO u32 nCount);


int main(void)
{
	uint8_t status=0;

	/* LED 端口初始化 */
	LED_GPIO_Config();
	LED_YELLOW;
	Delay(0xFFFFFF);

        MtM_DMA_Config();

	while( DMA_GetFlagStatus(MTM_DMA_FLAG_TC) == RESET );

	status = Buffercmp(aSRC_Const_Buffer,aDST_Buffer,BUFFER_SIZE);

	if( status == 0 )
  {
		LED_RED;
  }
  else
  {
		LED_GREEN;
	}

	while (1)
	{

	}
}

void Delay(__IO uint32_t nCount)	 //簡單的延時函數
{
	for(; nCount != 0; nCount--);
}