STM32USART DMA_Interrupt例程的学习

这是固件库里的一个例程，决定从这里入手依次学习一下外设，下面是这个例程的介绍：

This example provides a basic communication between USART1 and USART2 using DMA 

capability, flags and interrupts.

First, the DMA transfers data from TxBuffer2 buffer to USART2 Transmit data register,

then this data is sent to USART1. Data received by USART1 is transferred using 

RXNE flag and stored in RxBuffer1 then compared with the sent ones and

the result of this comparison is stored in the "TransferStatus1" variable.

In the same time, the DMA transfers data from TxBuffer1 buffer to USART1 Transmit

data register, then this data is sent to USART2. Data received by USART2 is

transferred using Receive interrupt and stored in RxBuffer2 then compared with

the sent ones and the result of this comparison is stored in the "TransferStatus2"

variable. 

按照意思无非是串口传输的数据和DMA传输的数据进行比对，然后返回状态，程序比较简单，很多地方我加了注释。

/******************** (C) COPYRIGHT 2008 STMicroelectronics ******************** * File Name : main.c * Author : MCD Application Team * Version : V2.0.1 * Date : 06/13/2008 * Description : Main program body ******************************************************************************** * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME. * AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT, * INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE * CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING * INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS. *******************************************************************************/ /* Includes ------------------------------------------------------------------*/ #include "stm32f10x_lib.h" #include "platform_config.h" /* Private typedef -----------------------------------------------------------*/ typedef enum {FAILED = 0, PASSED = !FAILED} TestStatus; /* Private define ------------------------------------------------------------*/ #define USART1_DR_Base 0x40013804 #define USART2_DR_Base 0x40004404 #define TxBufferSize1 (countof(TxBuffer1) - 1) #define TxBufferSize2 (countof(TxBuffer2) - 1) /* Private macro -------------------------------------------------------------*/ #define countof(a) (sizeof(a) / sizeof(*(a))) /* Private variables ---------------------------------------------------------*/ USART_InitTypeDef USART_InitStructure; u8 TxBuffer1[] = "USART DMA Interrupt: USART1 -> USART2 using DMA Tx and Rx Flag"; u8 TxBuffer2[] = "USART DMA Interrupt: USART2 -> USART1 using DMA Tx and Rx Interrupt"; u8 RxBuffer1[TxBufferSize2]; u8 RxBuffer2[TxBufferSize1]; u8 NbrOfDataToRead = TxBufferSize1; u8 index = 0; volatile TestStatus TransferStatus1 = FAILED, TransferStatus2 = FAILED; ErrorStatus HSEStartUpStatus; /* Private function prototypes -----------------------------------------------*/ void RCC_Configuration(void); void GPIO_Configuration(void); void NVIC_Configuration(void); void DMA_Configuration(void); TestStatus Buffercmp(u8* pBuffer1, u8* pBuffer2, u16 BufferLength); /* Private functions ---------------------------------------------------------*/ /******************************************************************************* * Function Name : main * Description : Main program * Input : None * Output : None * Return : None *******************************************************************************/ int main(void) { #ifdef DEBUG debug(); #endif /* System Clocks Configuration */ RCC_Configuration(); /* NVIC configuration */ NVIC_Configuration(); /* Configure the GPIO ports */ GPIO_Configuration(); /* Configure the DMA */ DMA_Configuration(); /* USART1 and USART2 configuration ------------------------------------------------------*/ /* USART and USART2 configured as follow: - BaudRate = 230400 baud 波特率设置 - Word Length = 8 Bits 数据位 - One Stop Bit 停止位 - No parity 无奇偶校验 - Hardware flow control disabled (RTS and CTS signals)无硬件流控制 - Receive and transmit enabled 接收和发送使能 */ USART_InitStructure.USART_BaudRate = 230400; USART_InitStructure.USART_WordLength = USART_WordLength_8b; USART_InitStructure.USART_StopBits = USART_StopBits_1; USART_InitStructure.USART_Parity = USART_Parity_No; USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; /* Configure USART1 */ USART_Init(USART1, &USART_InitStructure); /* Configure USART2 */ USART_Init(USART2, &USART_InitStructure); /*********************使能相应的DMA通道**************************/ /* Enable USART1 DMA TX request */ USART_DMACmd(USART1, USART_DMAReq_Tx, ENABLE); /* Enable USART2 DMA TX request */ USART_DMACmd(USART2, USART_DMAReq_Tx, ENABLE); /* Enable the USART2 Receive Interrupt */ USART_ITConfig(USART2, USART_IT_RXNE, ENABLE); /* Enable DMA1 Channel4 */ DMA_Cmd(DMA1_Channel4, ENABLE); /* Enable DMA1 Channel7 */ DMA_Cmd(DMA1_Channel7, ENABLE); /* Enable the USART1 */ USART_Cmd(USART1, ENABLE); /* Enable the USART2 */ USART_Cmd(USART2, ENABLE); /* Receive the TxBuffer2 */ while(index < TxBufferSize2) { while(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET) //检查接收标志位，如果一直没有接收到就在这儿循环 { } RxBuffer1[index++] = USART_ReceiveData(USART1); } /* Wait until DMA1_Channel 4 Transfer Complete */ while (DMA_GetFlagStatus(DMA1_FLAG_TC4) == RESET) { } /* Wait until DMA1_Channel 7 Transfer Complete */ while (DMA_GetFlagStatus(DMA1_FLAG_TC7) == RESET) { } /* Check the received data with the send ones */ TransferStatus1 = Buffercmp(TxBuffer2, RxBuffer1, TxBufferSize2); /* TransferStatus1 = PASSED, if the data transmitted from USART2 and received by USART1 are the same */ /* TransferStatus1 = FAILED, if the data transmitted from USART2 and received by USART1 are different */ TransferStatus2 = Buffercmp(TxBuffer1, RxBuffer2, TxBufferSize1); /* TransferStatus2 = PASSED, if the data transmitted from USART1 and received by USART2 are the same */ /* TransferStatus2 = FAILED, if the data transmitted from USART1 and received by USART2 are different */ while (1) { } } /******************************************************************************* * Function Name : RCC_Configuration * Description : Configures the different system clocks. * Input : None * Output : None * Return : None *******************************************************************************/ void RCC_Configuration(void) { /* RCC system reset(for debug purpose) */ RCC_DeInit(); /* Enable HSE */ RCC_HSEConfig(RCC_HSE_ON); /* Wait till HSE is ready */ HSEStartUpStatus = RCC_WaitForHSEStartUp(); if(HSEStartUpStatus == SUCCESS) { /* Enable Prefetch Buffer */ FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable); /* Flash 2 wait state */ FLASH_SetLatency(FLASH_Latency_2); /* HCLK = SYSCLK */ RCC_HCLKConfig(RCC_SYSCLK_Div1); /* PCLK2 = HCLK */ RCC_PCLK2Config(RCC_HCLK_Div1); /* PCLK1 = HCLK/2 */ RCC_PCLK1Config(RCC_HCLK_Div2); /* PLLCLK = 8MHz * 9 = 72 MHz */ RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9); /* Enable PLL */ RCC_PLLCmd(ENABLE); /* Wait till PLL is ready */ while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET) { } /* Select PLL as system clock source */ RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); /* Wait till PLL is used as system clock source */ while(RCC_GetSYSCLKSource() != 0x08) { } } /* DMA clock enable */ RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); /* Enable USART1, GPIOA, GPIOx and AFIO clocks */ RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOx | RCC_APB2Periph_AFIO, ENABLE); /* Enable USART2 clock */ RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE); } /******************************************************************************* * Function Name : GPIO_Configuration * Description : Configures the different GPIO ports. * Input : None * Output : None * Return : None *******************************************************************************/ void GPIO_Configuration(void) { GPIO_InitTypeDef GPIO_InitStructure; #ifdef USE_STM3210B_EVAL /* Enable the USART2 Pins Software Remapping 引脚重映射，在STM32中很多外设和相关的引脚可以重映射到其他引脚上*/ GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE); #endif /* Configure USART1 Rx (PA.10) as input floating 串口的接收引脚使用浮空输入的模式具体配置为什么形式需要查找技术手册 */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOA, &GPIO_InitStructure); /* Configure USART2 Rx as input floating */ GPIO_InitStructure.GPIO_Pin = GPIO_RxPin; GPIO_Init(GPIOx, &GPIO_InitStructure); /* Configure USART1 Tx (PA.09) as alternate function push-pull 发送引脚使用复用推挽输出*/ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOA, &GPIO_InitStructure); /* Configure USART2 Tx as alternate function push-pull */ GPIO_InitStructure.GPIO_Pin = GPIO_TxPin; GPIO_Init(GPIOx, &GPIO_InitStructure); } /******************************************************************************* * Function Name : NVIC_Configuration * Description : Configures the nested vectored interrupt controller. * Input : None * Output : None * Return : None *******************************************************************************/ void NVIC_Configuration(void) { NVIC_InitTypeDef NVIC_InitStructure; #ifdef VECT_TAB_RAM /* Set the Vector Table base location at 0x20000000 */ NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0); #else /* VECT_TAB_FLASH */ /* Set the Vector Table base location at 0x08000000 */ NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0); #endif /* Enable the USART2 Interrupt */ NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQChannel; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); } /******************************************************************************* * Function Name : DMA_Configuration * Description : Configures the DMA. * Input : None * Output : None * Return : None *******************************************************************************/ void DMA_Configuration(void) { DMA_InitTypeDef DMA_InitStructure; /* DMA1 Channel4 (triggered by USART1 Tx event) Config 每个通道都有固定的外设请求，因此在需要传输外设数据时需要选择对应的通道*/ DMA_DeInit(DMA1_Channel4); DMA_InitStructure.DMA_PeripheralBaseAddr = USART1_DR_Base; //定义了外设地址 DMA_InitStructure.DMA_MemoryBaseAddr = (u32)TxBuffer1; //定义了目的地址 DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; //外设作为数据的目的地 DMA_InitStructure.DMA_BufferSize = TxBufferSize1; //传送数据缓存大小 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //定义地址在传送后是否会递增 DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存到内存后地址递增 DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//数据宽度是8位 DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; //工作在正常缓存模式，还有一种是循环缓存模式 DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh; //通道拥有高优先级 DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//用来设置是否是内存到内存传输 DMA_Init(DMA1_Channel4, &DMA_InitStructure); /* DMA1 Channel7 (triggered by USART2 Tx event) Config 通道7的工作模式只需要把不一样的部分设置一下就可以，其他的还和上面一样*/ DMA_DeInit(DMA1_Channel7); DMA_InitStructure.DMA_PeripheralBaseAddr = USART2_DR_Base; DMA_InitStructure.DMA_MemoryBaseAddr = (u32)TxBuffer2; DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; DMA_InitStructure.DMA_BufferSize = TxBufferSize2; DMA_Init(DMA1_Channel7, &DMA_InitStructure); } /******************************************************************************* * Function Name : Buffercmp * Description : Compares two buffers. * Input : - pBuffer1, pBuffer2: buffers to be compared. * : - BufferLength: buffer's length * Output : None * Return : PASSED: pBuffer1 identical to pBuffer2 * FAILED: pBuffer1 differs from pBuffer2 用来比较两段是否相同 *******************************************************************************/ TestStatus Buffercmp(u8* pBuffer1, u8* pBuffer2, u16 BufferLength) { while(BufferLength--) { if(*pBuffer1 != *pBuffer2) { return FAILED; } pBuffer1++; pBuffer2++; } return PASSED; } #ifdef DEBUG /******************************************************************************* * Function Name : assert_failed * Description : Reports the name of the source file and the source line number * where the assert_param error has occurred. * Input : - file: pointer to the source file name * - line: assert_param error line source number * Output : None * Return : None *******************************************************************************/ void assert_failed(u8* file, u32 line) { /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d/r/n", file, line) */ /* Infinite loop */ while (1) { } } #endif /******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/