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DMA+USART+stm32

2024-11-22 18:06:01   203人阅读

众所周知，串口是按照字节传输的，每一次传输一个字节。要传一帧数据，需要按照协议，帧头，帧尾，长度等信息，从字节流里面去分离。或者按照超时去分离。
STM32里面提供了DMA传输方式，整个过程有硬件控制。不占用处理器时间，高效。
发包：采用DMA方式，DMA发包完成会生成一个DMA发包完成中断。
收包：采用DMA+串口空闲中断方式，DMA空闲中断在，收到串口数据，串口空闲1个字节，自动触发。
代码如下：
第一步：引脚和时钟初始化
  1. void GPIO_Configuration(void)
  2. {
  3.         GPIO_InitTypeDef GPIO_InitStructure;
  4.         /* 使能USART1 时钟和所在端口时钟 */
  5.         RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
  6.         RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
  7.         /*初始化USART1_TX端口*/
  8.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  9.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  10.         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  11.         GPIO_Init(GPIOA, &GPIO_InitStructure);
  12.         /*初始化USART1_RX端口  */
  13.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  14.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  15. 				GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  16.         GPIO_Init(GPIOA, &GPIO_InitStructure);
  17. 		
  18.         /* 使能USART2时钟和USART2所占用引脚的时钟 */
  19.         //RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
  20.         RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
  21.         /* 初始化USART2_Tx时钟 */
  22.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
  23.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  24.         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  25.         GPIO_Init(GPIOA, &GPIO_InitStructure);
  26.          /* 初始化USART2_Rx时钟 */
  27.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
  28.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  29.         GPIO_Init(GPIOA, &GPIO_InitStructure);    
  30.         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;        
  31.         GPIO_Init(GPIOA, &GPIO_InitStructure);				
				/*初始化RS485引脚 */																			   
				GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;	
				GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;   
				GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; 
				GPIO_Init ( GPIOA, & GPIO_InitStructure );	
  1. }
第二步：串口配置
  1. void USART_Configuration(void)
  2. {
  3.         USART_InitTypeDef USART_InitStructure;
  4.         /* USART1 115200 n  8  1 */
  5.         USART_InitStructure.USART_BaudRate = 115200;
  6.         USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  7.         USART_InitStructure.USART_StopBits = USART_StopBits_1;
  8.         USART_InitStructure.USART_Parity = USART_Parity_No;
  9.         USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  10.         USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  11.         USART_Init(USART1, &USART_InitStructure);
  12.         //开串口空闲中断
  13.         USART_ITConfig(USART1, USART_IT_IDLE , ENABLE);
  14. 		//使能USART1
  15.         USART_Cmd(USART1, ENABLE);
  16.         USART_ClearFlag(USART1, USART_FLAG_TC);
  17. 		
  18. 		/*usart2 115200 n 8 1*/
  19.         USART_InitStructure.USART_BaudRate = 115200;
  20.         USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  21.         USART_InitStructure.USART_StopBits = USART_StopBits_1;
  22.         USART_InitStructure.USART_Parity = USART_Parity_No;
  23.         USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  24.         USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  25.         USART_Init(USART2, &USART_InitStructure);
  26. 		//开串口空闲中断
  27.         USART_ITConfig(USART2, USART_IT_IDLE , ENABLE);
  28. 	    //使能USART2
  29.         USART_Cmd(USART2, ENABLE);
  30.         USART_ClearFlag(USART2, USART_FLAG_TC); 
  31. }
第三步：DMA设置
  1. void DMA_Configuration(void)
  2. {
  3. 		DMA_InitTypeDef DMA_InitStructure;
  4. 		/* DMA clock enable */
  5. 		RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);//DMA1
  7. 		/* DMA1 Channel4 (triggered by USART1 Tx event) Config */
  8. 		DMA_DeInit(DMA1_Channel4);
  9. 		DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40013804;
  10. 		DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART1_SEND_DATA;
  11. 		DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  12. 		DMA_InitStructure.DMA_BufferSize = 128;
  13. 		DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  14. 		DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  15. 		DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  16. 		DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  17. 		DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  18. 		DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  19. 		DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  20. 		DMA_Init(DMA1_Channel4, &DMA_InitStructure);
  21. 	
  22. 		DMA_ITConfig(DMA1_Channel4, DMA_IT_TC, ENABLE);
  23. 		DMA_ITConfig(DMA1_Channel4, DMA_IT_TE, ENABLE);
  24. 		/* Enable USART1 DMA TX request */
  25. 		USART_DMACmd(USART1, USART_DMAReq_Tx, ENABLE);
  26. 		DMA_Cmd(DMA1_Channel4, DISABLE);
  28. 		/* DMA1 Channel7 (triggered by USART2 Tx event) Config */
  29. 		DMA_DeInit(DMA1_Channel7);
  30. 		DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40004404;
  31. 		DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART2_SEND_DATA;
  32. 		DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  33. 		DMA_InitStructure.DMA_BufferSize = 128;
  34. 		DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  35. 		DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  36. 		DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  37. 		DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  38. 		DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  39. 		DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  40. 		DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  41. 		DMA_Init(DMA1_Channel7, &DMA_InitStructure);
  42. 		
  43. 		DMA_ITConfig(DMA1_Channel7, DMA_IT_TC, ENABLE);
  44. 		DMA_ITConfig(DMA1_Channel7, DMA_IT_TE, ENABLE);
  45. 		/* Enable USART1 DMA TX request */
  46. 		USART_DMACmd(USART2, USART_DMAReq_Tx, ENABLE);
  47. 		DMA_Cmd(DMA1_Channel7, DISABLE);
  50. 		/* DMA1 Channel5 (triggered by USART1 Rx event) Config */
  51. 		DMA_DeInit(DMA1_Channel5);
  52. 		DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40013804;
  53. 		DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART1_RECEIVE_DATA;
  54. 		DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  55. 		DMA_InitStructure.DMA_BufferSize = 128;
  56. 		DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  57. 		DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  58. 		DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  59. 		DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  60. 		DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  61. 		DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  62. 		DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  63. 		DMA_Init(DMA1_Channel5, &DMA_InitStructure);
  64. 		DMA_ITConfig(DMA1_Channel5, DMA_IT_TC, ENABLE);
  65. 		DMA_ITConfig(DMA1_Channel5, DMA_IT_TE, ENABLE);
  66. 		/* Enable USART1 DMA RX request */
  67. 		USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);
  68. 		DMA_Cmd(DMA1_Channel5, ENABLE);
  70. 		/* DMA1 Channel6 (triggered by USART1 Rx event) Config */
  71. 		DMA_DeInit(DMA1_Channel6);
  72. 		DMA_InitStructure.DMA_PeripheralBaseAddr = 0x40004404;
  73. 		DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART2_RECEIVE_DATA;
  74. 		DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  75. 		DMA_InitStructure.DMA_BufferSize = 128;
  76. 		DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  77. 		DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  78. 		DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  79. 		DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  80. 		DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  81. 		DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
  82. 		DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  83. 		DMA_Init(DMA1_Channel6, &DMA_InitStructure);
  84. 		DMA_ITConfig(DMA1_Channel6, DMA_IT_TC, ENABLE);
  85. 		DMA_ITConfig(DMA1_Channel6, DMA_IT_TE, ENABLE);
  86. 		/* Enable USART2 DMA RX request */
  87. 		USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);
  88. 		DMA_Cmd(DMA1_Channel6, ENABLE);
  89. }
第四步：NVIC中断配置
  1. void NVIC_Configuration(void)
  2. {
  3. 		NVIC_InitTypeDef NVIC_InitStructure;
  4. 		/* Configure one bit for preemption priority */
  5. 		NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  6. 		/* Enable the USART1 Interrupt串口空闲中断 */
  7. 		NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  8. 		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
  9. 		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  10. 		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  11. 		NVIC_Init(&NVIC_InitStructure);
  12. 		/* Enable the USART2 Interrupt 串口空闲中断 */
  13. 		NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  14. 		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
  15. 		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
  16. 		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  17. 		NVIC_Init(&NVIC_InitStructure);
  18. 		//Enable DMA Channel4 Interrupt DMA 发包完成中断 
  19. 		NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel4_IRQn;
  20. 		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  21. 		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  22. 		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  23. 		NVIC_Init(&NVIC_InitStructure);
  24. 		//Enable DMA Channel7 Interrupt  DMA 发包完成中断
  25. 		NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel7_IRQn;
  26. 		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  27. 		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
  28. 		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  29. 		NVIC_Init(&NVIC_InitStructure);
  30. }
第五步：串口空闲中断配置
  1. void USART1_IRQHandler(void)
  2. {
  3.         u16 DATA_LEN;
  4.         if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)//收包完成，触发空闲中断
  5.         {
  6.                 DMA_Cmd(DMA1_Channel5, DISABLE);//关掉DMA防干扰
  7.                 DATA_LEN=128-DMA_GetCurrDataCounter(DMA1_Channel5); //计算长度
  8.                 if(DATA_LEN > 0)
  9.                 {                        
  10.                    //数据处理    
  11.                                             
  12.                 }
  13.                 DMA_ClearFlag(DMA1_FLAG_GL5 | DMA1_FLAG_TC5 | DMA1_FLAG_TE5 | DMA1_FLAG_HT5);//清楚中断标志位，方便下一次接收
  14.                 DMA1_Channel5->CNDTR = 128;//
  15.                 USART1->SR;
  16.                 USART1->DR;
  17. 								
  18. 					   DMA_ClearITPendingBit(DMA1_IT_TC5);
  19. 					   DMA_ClearITPendingBit(DMA1_IT_TE5);
  20. 					   DMA_Cmd(DMA1_Channel5, DISABLE);//
  21. 					   DMA1_Channel5->CNDTR = 128;//?
  22. 					   DMA_Cmd(DMA1_Channel5, ENABLE);//
  23.         }
  24.         if(USART_GetITStatus(USART1, USART_IT_PE | USART_IT_FE | USART_IT_NE) != RESET)//
  25.         {
  26.                 USART_ClearITPendingBit(USART1, USART_IT_PE | USART_IT_FE | USART_IT_NE);
  27.         }
  28.         USART_ClearITPendingBit(USART1, USART_IT_TC);
  29.         USART_ClearITPendingBit(USART1, USART_IT_IDLE);
  30. }
  31. void USART2_IRQHandler(void)
  32. {
  33.         u16 DATA_LEN;
  34.         if(USART_GetITStatus(USART2, USART_IT_IDLE) != RESET) //?????????
  35.         {
  36.                 DMA_Cmd(DMA1_Channel6, DISABLE);
  37.                 DATA_LEN=512-DMA_GetCurrDataCounter(DMA1_Channel6); 
  38.                 if(DATA_LEN > 0)
  39.                 {                        
  40.            
  41.                 }
  42.                 //DMA_Cmd(DMA1_Channel5, DISABLE);//??DMA,?????????
  43.                 DMA_ClearFlag(DMA1_FLAG_GL6 | DMA1_FLAG_TC6 | DMA1_FLAG_TE6 | DMA1_FLAG_HT6);//???
  44.                 DMA1_Channel6->CNDTR = 512;//???
  45.                 DMA_Cmd(DMA1_Channel6, ENABLE);//???,??DMA
  46.                 //?SR??DR??Idle
  47.                 USART2->SR;
  48.                 USART2->DR;	
  49. 				DMA_ClearITPendingBit(DMA1_IT_TC6);
  50. 				DMA_ClearITPendingBit(DMA1_IT_TE6);
  51. 				DMA_Cmd(DMA1_Channel6, DISABLE);//
  52. 				DMA1_Channel6->CNDTR = 128;//?
  53. 				DMA_Cmd(DMA1_Channel6, ENABLE);//
  54. 								
  55.         }
  56.         if(USART_GetITStatus(USART2, USART_IT_PE | USART_IT_FE | USART_IT_NE) != RESET)//??
  57.         {
  58.                 USART_ClearITPendingBit(USART2, USART_IT_PE | USART_IT_FE | USART_IT_NE);
  59.         }
  60.         USART_ClearITPendingBit(USART2, USART_IT_TC);
  61.         USART_ClearITPendingBit(USART2, USART_IT_IDLE);
  62. }
第六步：DMA发包
  1. void usart1_DMA_send_data(int DATA_LEN)
  2. {
  3. 		DMA_Cmd(DMA1_Channel4, DISABLE); 
  4. 		DMA1_Channel4->CNDTR=DATA_LEN; //DMA1
  5. 		DMA_Cmd(DMA1_Channel4, ENABLE);   
  6. }
  8. void usart2_DMA_send_data(int DATA_LEN)
  9. {
  10. 		DMA_Cmd(DMA1_Channel7, DISABLE); //
  11. 		DMA1_Channel7->CNDTR=DATA_LEN; //DMA1,?????
  12. 		DMA_Cmd(DMA1_Channel7, ENABLE);                  
  13. }
第7步： 配置发包完成中断
  1. //DMA1_Channel4
  2. void DMA1_Channel4_IRQHandler(void)
  3. {
  4. 	DMA_ClearITPendingBit(DMA1_IT_TC4);
  5. 	DMA_ClearITPendingBit(DMA1_IT_TE4);
  6. 	DMA_Cmd(DMA1_Channel4, DISABLE);//
  7. }
  8. //DMA1_Channel7
  9. void DMA1_Channel7_IRQHandler(void)
  10. {
  11. 	DMA_ClearITPendingBit(DMA1_IT_TC7);
  12. 	DMA_ClearITPendingBit(DMA1_IT_TE7);
  13. 	DMA_Cmd(DMA1_Channel7, DISABLE);
  14. }
第8步：RS485首发引脚配置
  1. void set_RS485_TX_mode()
  2. {
  3. 	int cnt = 72000;
  4. 	PAout(8) =1;
  5. 	while(cnt--);
  6. }
  8. void set_RS485_Rx_mode()
  9. {
  10. 	int cnt = 72000;
  11. 	while(cnt--);
  12. 	PAout(8) =0;
  13. }
第9步 DMA发包封装:
  1. void rs485_DMA_send_data(uint8_t* data,uint8_t size)
  2. {
  3. 	set_RS485_TX_mode();
  4. 	memcpy(USART1_SEND_DATA,data,size);
  5. 	usart1_DMA_send_data(size);	
  6. 	set_RS485_Rx_mode();
  8. }
  10. void USART_DMA_send_data(uint8_t* data,uint8_t size)
  11. {
  12. 	memcpy(USART2_SEND_DATA,data,size);
  13. 	usart2_DMA_send_data(size);	
  14. }
以上就是全部的API。经测试收发数据都正常。






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DMA+USART+stm32


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