DMA存儲器到外設代碼講解

實驗目的:

bsp_dma_mtp.h

#ifndef __BSP_DMA_MTP_H
#define __BSP_DMA_MTP_H#include "stm32f10x.h"
#include <stdio.h>// 串口工作參數宏定義
#define  DEBUG_USARTx                   USART1
#define  DEBUG_USART_CLK                RCC_APB2Periph_USART1
#define  DEBUG_USART_APBxClkCmd         RCC_APB2PeriphClockCmd
#define  DEBUG_USART_BAUDRATE           115200// USART GPIO 引腳宏定義
#define  DEBUG_USART_GPIO_CLK           (RCC_APB2Periph_GPIOA)
#define  DEBUG_USART_GPIO_APBxClkCmd    RCC_APB2PeriphClockCmd#define  DEBUG_USART_TX_GPIO_PORT       GPIOA
#define  DEBUG_USART_TX_GPIO_PIN        GPIO_Pin_9
#define  DEBUG_USART_RX_GPIO_PORT       GPIOA
#define  DEBUG_USART_RX_GPIO_PIN        GPIO_Pin_10#define  USART_TX_DMA_CLK               RCC_AHBPeriph_DMA1
#define  USART_TX_DMA_CHANNEL           DMA1_Channel4
#define  USART_TX_DMA_FLAG_TC           DMA1_FLAG_TC4
#define  USART_DR_ADDRESS               (USART1_BASE+0x04)#define  SENDBUFF_SIZE                   5000void USARTx_DMA_Config(void);
void USART_Config(void);
#endif  /* __BSP_DMA_MTP_H */

?

?

bsp_dma_mtp.c

#include "bsp_dma_mtp.h"uint8_t SendBuff[SENDBUFF_SIZE];/*** @brief  USART GPIO 配置,工作參數配置* @param  無* @retval 無*/
void USART_Config(void)
{GPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;// 打開串口GPIO的時鐘DEBUG_USART_GPIO_APBxClkCmd(DEBUG_USART_GPIO_CLK, ENABLE);// 打開串口外設的時鐘DEBUG_USART_APBxClkCmd(DEBUG_USART_CLK, ENABLE);// 將USART Tx的GPIO配置為推挽復用模式GPIO_InitStructure.GPIO_Pin = DEBUG_USART_TX_GPIO_PIN;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(DEBUG_USART_TX_GPIO_PORT, &GPIO_InitStructure);// 將USART Rx的GPIO配置為浮空輸入模式GPIO_InitStructure.GPIO_Pin = DEBUG_USART_RX_GPIO_PIN;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_Init(DEBUG_USART_RX_GPIO_PORT, &GPIO_InitStructure);// 配置串口的工作參數// 配置波特率USART_InitStructure.USART_BaudRate = DEBUG_USART_BAUDRATE;// 配置 針數據字長USART_InitStructure.USART_WordLength = USART_WordLength_8b;// 配置停止位USART_InitStructure.USART_StopBits = USART_StopBits_1;// 配置校驗位USART_InitStructure.USART_Parity = USART_Parity_No ;// 配置硬件流控制USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;// 配置工作模式，收發一起USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;// 完成串口的初始化配置USART_Init(DEBUG_USARTx, &USART_InitStructure);// 使能串口USART_Cmd(DEBUG_USARTx, ENABLE);
}///重定向c庫函數printf到串口，重定向后可使用printf函數
int fputc(int ch, FILE *f)
{/* 發送一個字節數據到串口 */USART_SendData(DEBUG_USARTx, (uint8_t) ch);/* 等待發送完畢 */while (USART_GetFlagStatus(DEBUG_USARTx, USART_FLAG_TXE) == RESET);return (ch);
}// Memory -> P (USART->DR)
void USARTx_DMA_Config(void)
{DMA_InitTypeDef DMA_InitStruct;RCC_AHBPeriphClockCmd(USART_TX_DMA_CLK, ENABLE);DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)USART_DR_ADDRESS;DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)SendBuff;DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralDST;DMA_InitStruct.DMA_BufferSize = SENDBUFF_SIZE;DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;DMA_InitStruct.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;DMA_InitStruct.DMA_Priority = DMA_Priority_High;DMA_InitStruct.DMA_M2M = DMA_M2M_Disable;DMA_Init(USART_TX_DMA_CHANNEL, &DMA_InitStruct);DMA_ClearFlag(USART_TX_DMA_FLAG_TC);DMA_Cmd(USART_TX_DMA_CHANNEL, ENABLE);
}

?

main.c

#include "stm32f10x.h"
#include "bsp_led.h"
#include "bsp_dma_mtp.h"extern uint8_t SendBuff[SENDBUFF_SIZE];#define SOFT_DELAY Delay(0x0FFFFF);void Delay(__IO u32 nCount);/*** @brief  主函數* @param  無* @retval 無*/
int main(void)
{uint16_t i=0;/* LED 端口初始化 */LED_GPIO_Config();USART_Config();for(i=0; i<SENDBUFF_SIZE; i++){SendBuff[i] = 'P';}USARTx_DMA_Config();USART_DMACmd(DEBUG_USARTx, USART_DMAReq_Tx, ENABLE);while (1){LED1_TOGGLEDelay(0xFFFFF);}
}void Delay(__IO uint32_t nCount)	 //簡單的延時函數
{for(; nCount != 0; nCount--);
}