stm32 - DMA-直接存储器访问控制器 - 《单片机学习笔记》

DMA的作用
图表查看
通道概念
实战
- 开始DMA转化

DMA的作用

直接存储器访问(DMA)用于在外设于存储器之间以及存储器与存储器之间，提供高速数据传输。可以在无需任何CPU操作的情况下通过DMA快速移动数据。这样节省CPU资源可供其他操作使用。
- 总结：DMA的就是CPU的助手、数据搬运工。
DMA外设要点概括
- 对于DMA这个器间，它的功能就是建立起一个数据传输的通道。

图表查看

STM32F207VET6为例

DMA支持APB1和APB2总线和AHB1、AHB2总线的数据传输

通道概念

1、建立(选取)传输通道
- 存储器->存储器
- 外设->存储器
- 存储器->外设
2、确定传输对象
- 具体功能
  - UART(源)-内存(目标)
  - 内存数据(源)-UART(目标)
3、敲定传输细节
- 通道优先级
- 确定传输数据双方的数据格式
- 确定数据传输是否双方的数据格式
- 确定数据是否需要一直采集(循环模式是否使能)
- 是否需要传输标志/中断

实战

DMA句柄结构体
- DMA_HandleTypeDef
DMA初始化结构体
- DMA_InitTypeDef ```c typedef struct __DMA_HandleTypeDef { DMA_Stream_TypeDef Instance; /指向了具体的外设以及地址*/
DMA_InitTypeDef Init; /用来配置特定外设的参数配置，比如外设的功能(串口的波特率，奇偶校验位，停止位)/

HAL_LockTypeDef Lock; /锁/

__IO HAL_DMA_StateTypeDef State; /外设状态/

void *Parent;

void ( XferCpltCallback)( struct __DMA_HandleTypeDef hdma); /传输完成的回调函数/

void ( XferHalfCpltCallback)( struct __DMA_HandleTypeDef hdma);

void ( XferM1CpltCallback)( struct __DMA_HandleTypeDef hdma);

void ( XferM1HalfCpltCallback)( struct __DMA_HandleTypeDef hdma);

void ( XferErrorCallback)( struct __DMA_HandleTypeDef hdma);

void ( XferAbortCallback)( struct __DMA_HandleTypeDef hdma);

__IO uint32_t ErrorCode;

uint32_t StreamBaseAddress;

uint32_t StreamIndex;

}DMA_HandleTypeDef;


![image.png](https://cdn.nlark.com/yuque/0/2022/png/2322648/1658126688681-f5b86b6a-4103-46db-b830-ca822521e703.png#clientId=ubb24075a-1ac0-4&crop=0&crop=0&crop=1&crop=1&from=paste&height=730&id=u9edefd07&margin=%5Bobject%20Object%5D&name=image.png&originHeight=912&originWidth=1040&originalType=binary&ratio=1&rotation=0&showTitle=false&size=159220&status=done&style=none&taskId=u7487727f-6be0-4c83-b69f-dfa4ee2bcd4&title=&width=832)<br />![image.png](https://cdn.nlark.com/yuque/0/2022/png/2322648/1658126716407-fef36282-7aaa-4fd1-931c-65b012f7bc24.png#clientId=ubb24075a-1ac0-4&crop=0&crop=0&crop=1&crop=1&from=paste&height=735&id=ufc23f626&margin=%5Bobject%20Object%5D&name=image.png&originHeight=919&originWidth=1044&originalType=binary&ratio=1&rotation=0&showTitle=false&size=162275&status=done&style=none&taskId=ua1e4571b-3c7c-4a91-a649-268635b1aac&title=&width=835.2)<br />![image.png](https://cdn.nlark.com/yuque/0/2022/png/2322648/1658126744807-942a4cad-9b64-474d-9635-6323ed4d97b3.png#clientId=ubb24075a-1ac0-4&crop=0&crop=0&crop=1&crop=1&from=paste&height=735&id=u119d6427&margin=%5Bobject%20Object%5D&name=image.png&originHeight=919&originWidth=1044&originalType=binary&ratio=1&rotation=0&showTitle=false&size=138279&status=done&style=none&taskId=u9b3fa603-1179-406b-9ce9-9cd8c41d546&title=&width=835.2)<br />按照之前的步骤生成MDK工程<br />在各自的c文件中(比如usart.c文件中)<br />![image.png](https://cdn.nlark.com/yuque/0/2022/png/2322648/1658127095131-65df3fd6-ccb6-430d-b6a7-fdf179de38f1.png#clientId=ubb24075a-1ac0-4&crop=0&crop=0&crop=1&crop=1&from=paste&height=404&id=ue00c597b&margin=%5Bobject%20Object%5D&name=image.png&originHeight=505&originWidth=524&originalType=binary&ratio=1&rotation=0&showTitle=false&size=178545&status=done&style=none&taskId=u3b6cdb0f-88a2-431a-975c-85299c8c369&title=&width=419.2)
- Instance: DMA通道
- Direction
   - DMA_MEMORY_TO_MEMORY: 内存到内存的模式
   - DMA_MEMORY_TO_PERIPH: 内存到外设的模式
   - DMA_PERIPH_TO_MEMORY: 外设到内存的模式
- PeriphInc: 外设地址是否递增
   - DMA_PINC_ENABLE: 外设地址递增
   - DMA_PINC_DISABLE: 外设地址不递增
- MemInc: 内存地址是否递增
   - DMA_MINC_ENABLE: 内存地址递增
   - DMA_MINC_DISABLE: 内存地址不递增
- PeriphDataAlignment: 外设数据宽度
   - DMA_PDATAALIGN_BYTE: 外设的byte位
   - DMA_PDATAALIGN_HALFWORD: 外设的halfword位
   - DMA_PDATAALIGN_WORD: 外设的word位
- MemDataAlignment: 内存数据宽度
   - DMA_MDATAALIGN_BYTE: 内存的byte位
   - DMA_MDATAALIGN_BYTE: 内存的halfword位
   - DMA_MDATAALIGN_BYTE:  内存的word位
<a name="yBVQT"></a>
##### 中断配置
![image.png](https://cdn.nlark.com/yuque/0/2022/png/2322648/1658127850846-b8e5aa2d-fd81-4ada-871b-7626cb420c49.png#clientId=ubb24075a-1ac0-4&crop=0&crop=0&crop=1&crop=1&from=paste&height=239&id=ua1f1adaa&margin=%5Bobject%20Object%5D&name=image.png&originHeight=299&originWidth=423&originalType=binary&ratio=1&rotation=0&showTitle=false&size=92054&status=done&style=none&taskId=uf4159655-4644-4464-856a-962946fb248&title=&width=338.4)
- 中断初始化
<a name="Z5fNn"></a>
##### usart-DMA配置
- HAL_DMA_Init(&hdma_usart1_rx)  : DMA初始化
- __HAL_LINKDMA(uartHandle,hdmarx,hdma_usart1_rx); : 将串口的外设和DMA连接在了一起
   - uartHandle:串口的局柄
   - DMA的句柄
   - DMA外设初始化句柄
   - #define __HAL_LINKDMA(__HANDLE__, __PPP_DMA_FIELD__, __DMA_HANDLE__)               \
                        do{                                                      \<br />                              (__HANDLE__)->__PPP_DMA_FIELD__ = &(__DMA_HANDLE__); \<br />                              (__DMA_HANDLE__).Parent = (__HANDLE__);             \<br />                          } while(0U)
      - __HANDLE__: 用`->`指向了成员(结构体指针下的成员)
```c
...
//系统时钟初始化: 我设置的是72MHZ
void SystemClock_Config(void);
...

自己创建dma初始化(注释原来的)

#ifndef __BSP_DMA_H
#define __BSP_DMA_H
#include "stm32f1xx_hal_gpio.h"
#include "stm32f1xx_hal_dma.h"
void DMA_Config(void);
#endif

#include "bsp_dma.h"
DMA_HandleTypeDef DMA_Handle;
const int32_t TxBuffer[32]={    //发送缓冲区，定义在flash中，只读
    0x1000,0x2000,0x3000,0x4000,0x5000,0x6000
};
uint32_t RxBuffer[32];    //接收缓冲区
void DMA_Config(void){
    HAL_StatusTypeDef status = HAL_ERROR;
    __HAL_RCC_DMA1_CLK_ENABLE(); //开启DMA1时钟(使能)
    DMA_Handle.Instance = DMA1_Channel5;//Instance: 指向的是实际的通道
    //DMA_Handle.Init = ;//init:指向了外设的初始化的结构体
    /*
    #define IS_DMA_DIRECTION(DIRECTION) (((DIRECTION) == DMA_PERIPH_TO_MEMORY ) || \
                                     ((DIRECTION) == DMA_MEMORY_TO_PERIPH)  || \
                                     ((DIRECTION) == DMA_MEMORY_TO_MEMORY))
    */
    DMA_Handle.Init.Direction = DMA_PERIPH_TO_MEMORY;//外设到内存
    /*
    #define IS_DMA_PERIPHERAL_INC_STATE(STATE) (((STATE) == DMA_PINC_ENABLE) || \
                                            ((STATE) == DMA_PINC_DISABLE))
    */
    DMA_Handle.Init.PeriphInc=DMA_PINC_ENABLE; //外设递增使能
    /*
    #define IS_DMA_MEMORY_INC_STATE(STATE) (((STATE) == DMA_MINC_ENABLE)  || \
                                        ((STATE) == DMA_MINC_DISABLE))
    */
    DMA_Handle.Init.MemInc=DMA_MINC_DISABLE;//内存失能
    /*
    #define IS_DMA_PERIPHERAL_DATA_SIZE(SIZE) (((SIZE) == DMA_PDATAALIGN_BYTE)     || \
                                           ((SIZE) == DMA_PDATAALIGN_HALFWORD) || \
                                           ((SIZE) == DMA_PDATAALIGN_WORD))
    */
    DMA_Handle.Init.PeriphDataAlignment=DMA_PDATAALIGN_BYTE;//外设数据的长度
    /*
    #define IS_DMA_MEMORY_DATA_SIZE(SIZE) (((SIZE) == DMA_MDATAALIGN_BYTE)     || \
                                       ((SIZE) == DMA_MDATAALIGN_HALFWORD) || \
                                       ((SIZE) == DMA_MDATAALIGN_WORD ))
    */
    DMA_Handle.Init.MemDataAlignment=DMA_MDATAALIGN_BYTE;//内存数据的长度;DMA_MDATAALIGN_WORD: 32位=int
    /*
    #define IS_DMA_MODE(MODE) (((MODE) == DMA_NORMAL )  || \
                           ((MODE) == DMA_CIRCULAR))
    */
    DMA_Handle.Init.Mode=DMA_NORMAL;//外设普通模式;  DMA_CIRCULAR: 循环传输模式
    /*
    #define IS_DMA_PRIORITY(PRIORITY) (((PRIORITY) == DMA_PRIORITY_LOW )   || \
                                   ((PRIORITY) == DMA_PRIORITY_MEDIUM) || \
                                   ((PRIORITY) == DMA_PRIORITY_HIGH)   || \
                                   ((PRIORITY) == DMA_PRIORITY_VERY_HIGH))
    */
    DMA_Handle.Init.Priority=DMA_PRIORITY_MEDIUM;//配置优先级; DMA_PRIORITY_MEDIUM: 中等
    HAL_DMA_Init(&DMA_Handle);//传入句柄，进入初始化
}

开始DMA转化

/*
==============================================================================
                        ##### How to use this driver #####
  ==============================================================================
  [..]
   (#) Enable and configure the peripheral to be connected to the DMA Channel
       (except for internal SRAM / FLASH memories: no initialization is 
       necessary). Please refer to the Reference manual for connection between peripherals
       and DMA requests.
   (#) For a given Channel, program the required configuration through the following parameters:
       Channel request, Transfer Direction, Source and Destination data formats,
       Circular or Normal mode, Channel Priority level, Source and Destination Increment mode
       using HAL_DMA_Init() function.
   (#) Use HAL_DMA_GetState() function to return the DMA state and HAL_DMA_GetError() in case of error 
       detection.
   (#) Use HAL_DMA_Abort() function to abort the current transfer
     -@-   In Memory-to-Memory transfer mode, Circular mode is not allowed.
     *** Polling mode IO operation ***
     =================================
    [..]
          (+) Use HAL_DMA_Start() to start DMA transfer after the configuration of Source
              address and destination address and the Length of data to be transferred
          (+) Use HAL_DMA_PollForTransfer() to poll for the end of current transfer, in this
              case a fixed Timeout can be configured by User depending from his application.
     *** Interrupt mode IO operation ***
     ===================================
    [..]
          (+) Configure the DMA interrupt priority using HAL_NVIC_SetPriority()
          (+) Enable the DMA IRQ handler using HAL_NVIC_EnableIRQ()
          (+) Use HAL_DMA_Start_IT() to start DMA transfer after the configuration of
              Source address and destination address and the Length of data to be transferred.
              In this case the DMA interrupt is configured
          (+) Use HAL_DMA_IRQHandler() called under DMA_IRQHandler() Interrupt subroutine
          (+) At the end of data transfer HAL_DMA_IRQHandler() function is executed and user can
              add his own function by customization of function pointer XferCpltCallback and
              XferErrorCallback (i.e. a member of DMA handle structure).
     *** DMA HAL driver macros list ***
     ============================================= 
      [..]
       Below the list of most used macros in DMA HAL driver.
       (+) __HAL_DMA_ENABLE: Enable the specified DMA Channel.
       (+) __HAL_DMA_DISABLE: Disable the specified DMA Channel.
       (+) __HAL_DMA_GET_FLAG: Get the DMA Channel pending flags.
       (+) __HAL_DMA_CLEAR_FLAG: Clear the DMA Channel pending flags.
       (+) __HAL_DMA_ENABLE_IT: Enable the specified DMA Channel interrupts.
       (+) __HAL_DMA_DISABLE_IT: Disable the specified DMA Channel interrupts.
       (+) __HAL_DMA_GET_IT_SOURCE: Check whether the specified DMA Channel interrupt has occurred or not. 
     [..] 
*/

/**
  * @brief  Start the DMA Transfer.
  * @param  hdma: pointer to a DMA_HandleTypeDef structure that contains
  *               the configuration information for the specified DMA Channel.
  * @param  SrcAddress: The source memory Buffer address
  * @param  DstAddress: The destination memory Buffer address
  * @param  DataLength: The length of data to be transferred from source to destination
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_DMA_Start(DMA_HandleTypeDef *hdma, uint32_t SrcAddress, uint32_t DstAddress, uint32_t DataLength)
{
  HAL_StatusTypeDef status = HAL_OK;
  /* Check the parameters */
  assert_param(IS_DMA_BUFFER_SIZE(DataLength));
  /* Process locked */
  __HAL_LOCK(hdma);
  if(HAL_DMA_STATE_READY == hdma->State)
  {
    /* Change DMA peripheral state */
    hdma->State = HAL_DMA_STATE_BUSY;
    hdma->ErrorCode = HAL_DMA_ERROR_NONE;
    /* Disable the peripheral */
    __HAL_DMA_DISABLE(hdma);
    /* Configure the source, destination address and the data length & clear flags*/
    DMA_SetConfig(hdma, SrcAddress, DstAddress, DataLength);
    /* Enable the Peripheral */
    __HAL_DMA_ENABLE(hdma);
  }
  else
  {
   /* Process Unlocked */
   __HAL_UNLOCK(hdma);  
   status = HAL_BUSY;
  }  
  return status;
}

hdma: 指向了DMA的句柄结构体
SrcAddress: 原地址(内存地址) 我们文件中就是指TxBuffer
DstAddress: 目标的储存器(内存地址),我们的文件中就是指RxBuffer

DataLength: 传输的大小

void DMA_Config(void){
....
DMA_Status = HAL_DMA_Start(&DMA_Handle,(uint32_t)TxBuffer,(uint32_t)RxBuffer,32);
  /*判断DMA状态:  DMA_Status !=HAL_OK */
  if(DMA_Status !=HAL_OK){
      while(1){
          HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_5);
          HAL_Delay(1000);
      }
  }
}

完整函数

#include "bsp_dma.h"
DMA_HandleTypeDef DMA_Handle;
HAL_StatusTypeDef DMA_Status;
const int32_t TxBuffer[32]={    //发送缓冲区，定义在flash中，只读
    0x1000,0x2000,0x3000,0x4000,0x5000,0x6000
};
uint32_t RxBuffer[32];    //接收缓冲区
void DMA_Config(void){
    HAL_StatusTypeDef status = HAL_ERROR;
    __HAL_RCC_DMA1_CLK_ENABLE(); //开启DMA1时钟(使能)
    DMA_Handle.Instance = DMA1_Channel5;//Instance: 指向的是实际的通道
    //DMA_Handle.Init = ;//init:指向了外设的初始化的结构体
    /*
    #define IS_DMA_DIRECTION(DIRECTION) (((DIRECTION) == DMA_PERIPH_TO_MEMORY ) || \
                                     ((DIRECTION) == DMA_MEMORY_TO_PERIPH)  || \
                                     ((DIRECTION) == DMA_MEMORY_TO_MEMORY))
    */
    DMA_Handle.Init.Direction = DMA_PERIPH_TO_MEMORY;//外设到内存
    /*
    #define IS_DMA_PERIPHERAL_INC_STATE(STATE) (((STATE) == DMA_PINC_ENABLE) || \
                                            ((STATE) == DMA_PINC_DISABLE))
    */
    DMA_Handle.Init.PeriphInc=DMA_PINC_ENABLE; //外设递增使能
    /*
    #define IS_DMA_MEMORY_INC_STATE(STATE) (((STATE) == DMA_MINC_ENABLE)  || \
                                        ((STATE) == DMA_MINC_DISABLE))
    */
    DMA_Handle.Init.MemInc=DMA_MINC_DISABLE;//内存失能
    /*
    #define IS_DMA_PERIPHERAL_DATA_SIZE(SIZE) (((SIZE) == DMA_PDATAALIGN_BYTE)     || \
                                           ((SIZE) == DMA_PDATAALIGN_HALFWORD) || \
                                           ((SIZE) == DMA_PDATAALIGN_WORD))
    */
    DMA_Handle.Init.PeriphDataAlignment=DMA_PDATAALIGN_BYTE;//外设数据的长度
    /*
    #define IS_DMA_MEMORY_DATA_SIZE(SIZE) (((SIZE) == DMA_MDATAALIGN_BYTE)     || \
                                       ((SIZE) == DMA_MDATAALIGN_HALFWORD) || \
                                       ((SIZE) == DMA_MDATAALIGN_WORD ))
    */
    DMA_Handle.Init.MemDataAlignment=DMA_MDATAALIGN_BYTE;//内存数据的长度;DMA_MDATAALIGN_WORD: 32位=int
    /*
    #define IS_DMA_MODE(MODE) (((MODE) == DMA_NORMAL )  || \
                           ((MODE) == DMA_CIRCULAR))
    */
    DMA_Handle.Init.Mode=DMA_NORMAL;//外设普通模式;  DMA_CIRCULAR: 循环传输模式
    /*
    #define IS_DMA_PRIORITY(PRIORITY) (((PRIORITY) == DMA_PRIORITY_LOW )   || \
                                   ((PRIORITY) == DMA_PRIORITY_MEDIUM) || \
                                   ((PRIORITY) == DMA_PRIORITY_HIGH)   || \
                                   ((PRIORITY) == DMA_PRIORITY_VERY_HIGH))
    */
    DMA_Handle.Init.Priority=DMA_PRIORITY_MEDIUM;//配置优先级; DMA_PRIORITY_MEDIUM: 中等
    HAL_DMA_Init(&DMA_Handle);//传入句柄，进入初始化
    DMA_Status = HAL_DMA_Start(&DMA_Handle,(uint32_t)TxBuffer,(uint32_t)RxBuffer,32);
    /*判断DMA状态:  DMA_Status !=HAL_OK */
    if(DMA_Status !=HAL_OK){
        while(1){
            HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_5);
            HAL_Delay(1000);
        }
    }
}