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cms 做网站,南昌网站建设兼职,河南做网站的,php网站开发示例DMA: Data memory Access, 直接存储器访问。可以把数据从一个地方传输到另一个地方，而且不占用CPU。 DMA1: 7个通道，M->M,P->M,M->P. DMA2: 5个通道 , M->M,P->M,M->P. (存在大容量、互联型（f105/f107）产品中…

DMA: Data memory Access, 直接存储器访问。可以把数据从一个地方传输到另一个地方，而且不占用CPU。 DMA1: 7个通道，M->M,P->M,M->P. DMA2: 5个通道 , M->M,P->M,M->P. (存在大容量、互联型（f105/f107）产品中)

系统结构

DMA1请求映射

DMA2请求映射

多个DMA同时请求：

1.软件阶段，DMA_CCRx DMA通道配置寄存器PL--->设置通道优先级

2.硬件阶段，通道编号小的优先级大，DMA1优先级大于DMA2的优先级

下面用两种传输方向来介绍DMA结构体

1.M - > M: Flash to SRAM, 内部FLASH (CODE)的数据传输到内部的SRAM(变量)

2.M -> P : SRAM to 串口 + LED，延时DMA传输数据不需要占用CPU

注：当源端数据宽度和目标数据宽度不一样时可参考中文参考手册DMA模块数据对齐表

M->M:

1.在FLASH中定义好要传输的数据，在SRAM中定义好接收FLASH数据的变量

2.初始化DMA结构体

3.编写比较函数

4.main函数应用

dma.c:

#include "stm32f10x.h"
#include "dma.h"//const 关键字 把数组Buffer定义为常量类型，表示数据存储在内部的flash中
const uint32_t SRC_Buffer[BUFFER_SIZE] = {0x01020304,0x05060708,0x090A0B0C,0x0D0E0F10,0x11121314,0x15161718,0x191A1B1C,0x1D1E1F20,0x21222324,0x25262728,0x292A2B2C,0x2D2E2F30,0x31323334,0x35363738,0x393A3B3C,0x3D3E3F40};
//定义DMA传输的目标存储器，存储在内部SRAMuint32_t DST_BUFFER[BUFFER_SIZE];void DMA_MTM_Init(void)
{DMA_InitTypeDef  DMA_InitStruct;RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1,ENABLE);DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)SRC_Buffer;//外设地址DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)DST_BUFFER;//存储器地址DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralSRC;//传输方向，外设作为源DMA_InitStruct.DMA_BufferSize = BUFFER_SIZE;//传输数目DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Enable;//外设地址增量模式DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;//存储器地址增量模式DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;//外设数据宽度DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;//存储器数据宽度DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;//模式选择，循环发送还是只发送一次DMA_InitStruct.DMA_Priority = DMA_Priority_High;//通道优先级DMA_InitStruct.DMA_M2M = DMA_M2M_Enable;//存储器到存储器模式使能DMA_Init(DMA1_Channel6,&DMA_InitStruct);DMA_ClearFlag( DMA1_FLAG_TC6);//清除发送完成标志位DMA_Cmd(DMA1_Channel6,ENABLE);}
uint8_t Buffercmp(const uint32_t* pBffer1, uint32_t *pBffer2,uint32_t BfferLength)
{while(BfferLength--)//数据长度递减{if(*pBffer1 != *pBffer2)//判断两个数据源是否相等{return 0;          //对应数据源不相等返回0}pBffer1++;     //递增两个数据源地址指针pBffer2++;}return 1;    //完成判断并且对应数据源相等返回1
}

dma.h

#ifndef _DMA_H_
#define _DMA_H_
#include "stm32f10x.h"void DMA_MTM_Init(void);
uint8_t Buffercmp(const uint32_t* pBffer1, uint32_t *pBffer2,uint32_t BfferLength);
void USART_DMA_Init(void);#define BUFFER_SIZE 16
#define USART_DR_ADDR (USART1_BASE+0X04)
#define SEND_SIZE  500#endif

main.c

int main(void)
{uint8_t status = 0;extern const uint32_t SRC_Buffer[BUFFER_SIZE] ;extern  uint32_t DST_BUFFER[BUFFER_SIZE];LED_Init();DMA_MTM_Init();status = Buffercmp(SRC_Buffer,DST_BUFFER,BUFFER_SIZE);if(status == 0){GPIO_ResetBits(GPIOA,  GPIO_Pin_1);//如果返回值为0，则传输失败PA1引脚输出低电平led亮}else{GPIO_SetBits(GPIOA,  GPIO_Pin_1);//相反}while(1){}
}

M->P：

dma.c:


uint8_t SendBuffer[SEND_SIZE];
void USART_DMA_Init(void)
{DMA_InitTypeDef  DMA_InitStruct;RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1,ENABLE);DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)USART_DR_ADDR;//外设地址（串口1数据寄存器的地址）DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)SendBuffer;//存储器地址DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralDST;//传输方向，外设作为传输目标DMA_InitStruct.DMA_BufferSize = SEND_SIZE;//传输数目DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;//存储器地址增量模式DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设地址增量模式关闭DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外设数据宽度DMA_InitStruct.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;//存储器数据宽度DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;//模式选择只发送一次DMA_InitStruct.DMA_Priority = DMA_Priority_High;//通道优先级DMA_InitStruct.DMA_M2M = DMA_M2M_Disable;//存储器到存储器模式关闭DMA_Init(DMA1_Channel4,&DMA_InitStruct);//初始化DMA1通道4结构体DMA_ClearFlag( DMA1_FLAG_TC4);//清除发送完成标志位DMA_Cmd(DMA1_Channel4,ENABLE);//DMA1通道4使能}

dma.h

#ifndef _DMA_H_
#define _DMA_H_
#include "stm32f10x.h"void DMA_MTM_Init(void);
uint8_t Buffercmp(const uint32_t* pBffer1, uint32_t *pBffer2,uint32_t BfferLength);
void USART_DMA_Init(void);#define BUFFER_SIZE 16
#define USART_DR_ADDR (USART1_BASE+0X04)
#define SEND_SIZE  500#endif

usart.c

// USART1初始化void  myusart_init(void){GPIO_InitTypeDef GPIOInitStruct;USART_InitTypeDef USARTInitStruct;NVIC_InitTypeDef NVIC_Initstruct;NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1,ENABLE);//A9 TXGPIOInitStruct.GPIO_Mode = GPIO_Mode_AF_PP;GPIOInitStruct.GPIO_Speed = GPIO_Speed_10MHz;GPIOInitStruct.GPIO_Pin = GPIO_Pin_9;GPIO_Init(GPIOA,&GPIOInitStruct);//A10 RXGPIOInitStruct.GPIO_Mode = GPIO_Mode_IPU;GPIOInitStruct.GPIO_Pin = GPIO_Pin_10;GPIO_Init(GPIOA,&GPIOInitStruct);USARTInitStruct.USART_BaudRate = 115200;USARTInitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;USARTInitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;USARTInitStruct.USART_Parity = USART_Parity_No;USARTInitStruct.USART_StopBits = USART_StopBits_1;USARTInitStruct.USART_WordLength = USART_WordLength_8b;USART_Init(USART1,&USARTInitStruct);USART_Cmd(USART1,ENABLE);USART_ITConfig(USART1,  USART_IT_RXNE,ENABLE);NVIC_Initstruct.NVIC_IRQChannel = USART1_IRQn;NVIC_Initstruct.NVIC_IRQChannelPreemptionPriority = 0;NVIC_Initstruct.NVIC_IRQChannelSubPriority = 0;NVIC_Initstruct.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_Initstruct);}

main.c

int main(void)
{uint16_t i=0;extern uint8_t SendBuffer[SEND_SIZE];for(i=0;i<SEND_SIZE;i++){SendBuffer[i] = '0';}myusart_init();USART_DMA_Init();USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);while(1){}
}