串口DMA接收

如果才能提高串口回复速度?

发布于 2022-05-30 17:06:47 浏览：405 订阅该版

[tocm]

## 问题描述:  
我用DMA中断接收, 在中断回调中发送消息, 串口接收线程中解析数据并回复.  
整个过程数据响应没有问题, 从收到到回复大概是6ms. 但ProfibusDP响应要求达到2ms. 请问我有什么办法可以改进响应速度吗?
```c
//接收中断回调函数
static rt_err_t uart2_dma_callback(rt_device_t dev, rt_size_t size)
{
    /* 串口接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
    struct rx_msg msg;
    rt_err_t result;
    msg.dev = dev;
    msg.size = size;

result = rt_mq_send(&profidp_rx_mq, &msg, sizeof(msg));
    if ( result == -RT_EFULL)
    {
        /* 消息队列满 */
        rt_kprintf("message queue full！\n");
    }
    return result;
}
 
/*******************************************************************************
* @fn      serial_thread_entry(void *parameter)
*
* @brief   串口接收线程
*
* @param   none
*
* @return  none
*******************************************************************************/
static void serial_thread_entry(void *parameter)
{
    struct rx_msg msg;
    rt_mutex_t profidp_send_mx = RT_NULL;			//互斥信号量
    rt_err_t result;
    rt_uint16_t rx_length;
    //static rt_uint8_t rx_buffer[RT_SERIAL_RB_BUFSZ + 1];

profidp_send_mx = rt_mutex_create ("profidp_send_mx", RT_IPC_FLAG_FIFO);
    while (1)
    {
		rt_kprintf("serial_thread_entry tick is %ld\r\n", rt_tick_get());
		
		rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
        	rt_memset(&msg, 0, sizeof(msg));
		profibus_watchdog_proc();
		
        /* 从消息队列中读取消息*/
        result = rt_mq_recv(&profidp_rx_mq, &msg, sizeof(msg), RT_WAITING_NO/*RT_WAITING_FOREVER*/);
        if (result == RT_EOK)
        {
            /* 从串口读取数据*/
            rx_length = rt_device_read(msg.dev, 0, m_rtUsart2RxBuf, msg.size);
			if (rx_length >= 6 && rx_length < PROFIDP_RX_BUF_LEN)
			{
				//rx_buffer[rx_length] = '\0';
				//rt_memcpy(m_rtUsart2RxBuf, rx_buffer, rx_length);
				rt_kprintf("rx_length is %d tick is %ld\r\n", rx_length, rt_tick_get());

rt_mutex_take(profidp_send_mx, RT_WAITING_FOREVER);
				rt_pin_write(RS485_RX_TX_EN, PIN_HIGH);
				hw_profibusdp_rx_proc(m_rtUsart2RxBuf, rx_length);;
				rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
				rt_mutex_release(profidp_send_mx);
			}
		}
    }
}
 
/*******************************************************************************
* @fn      profibus_uart_init(void)
*
* @brief   串口初始化
*
* @param   none
*
* @return  none
*******************************************************************************/
int profibus_uart_init(void)
{
	rt_err_t open_result = RT_EOK;
	rt_pin_mode(RS485_RX_TX_EN, PIN_MODE_OUTPUT);	
	rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
	
	profibusdp_serial=rt_device_find(DP_UART_PORT_NAME);
	if(RT_NULL == profibusdp_serial)
	{
		rt_kprintf("uart2 find failed !\n");
	}
	else
	{
		hw_profibusdp_init();
		rt_mq_init(&profidp_rx_mq, "profidp_rx_mq" ,msg_pool, sizeof(struct rx_msg), sizeof(msg_pool), RT_IPC_FLAG_FIFO);
		profibusdp_uart_config.baud_rate = BAUD_RATE_9600;   
		profibusdp_uart_config.data_bits = DATA_BITS_9;          
		profibusdp_uart_config.stop_bits = STOP_BITS_1;         
		profibusdp_uart_config.bufsz     = PROFIDP_RX_BUF_LEN;                  
		profibusdp_uart_config.parity    = PARITY_EVEN;      
		
		rt_device_control(profibusdp_serial, RT_DEVICE_CTRL_CONFIG, &profibusdp_uart_config);
		
		open_result = rt_device_open(profibusdp_serial, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_DMA_RX);
        /* using interrupt mode when DMA mode not supported */
        if (open_result == -RT_EIO)
        {
            open_result = rt_device_open(profibusdp_serial, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX);
        }
		RT_ASSERT(open_result == RT_EOK);
		rt_device_set_rx_indicate(profibusdp_serial, uart2_dma_callback);
	}
	rt_thread_t thread = rt_thread_create("profidp_serial", serial_thread_entry, RT_NULL, 1024, 0, 10);
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
 
    return RT_EOK;
}
```

lchnu 2022-05-30

Witness, Understand, Skill

yc985055 2022-05-30

这家伙很懒，什么也没写！

lchnu 2022-05-30

Witness, Understand, Skill

lchnu 2022-05-30

Witness, Understand, Skill

yc985055 2022-05-31

这家伙很懒，什么也没写！

lchnu 2022-05-31

Witness, Understand, Skill

lchnu 2022-05-31

Witness, Understand, Skill

yc985055 2022-05-31

这家伙很懒，什么也没写！

yc985055 2022-06-02

这家伙很懒，什么也没写！

lchnu 2022-06-02

Witness, Understand, Skill

yc985055 2022-06-06

这家伙很懒，什么也没写！

lchnu 2022-06-06

Witness, Understand, Skill

yc985055 2022-06-06

这家伙很懒，什么也没写！

@lchnu 下面是裸奔的程序. 逻辑分析仪中它回复的字节间隔就是100us左右, 相当于1个停止位? rtthread中有没有办法去掉起始位或停止位, 我去其一试试

#include "stm32f10x.h"

#include "main.h"
#include "run.h"
#include "usart.h"
#include "usart1.h"

/*RE跟GPIOC5管脚相连*/   
#define Set_RE  GPIO_SetBits(GPIOC,GPIO_Pin_5);			 
#define Clr_RE  GPIO_ResetBits(GPIOC,GPIO_Pin_5);
/*DE跟GPIOC4管脚相连*/
#define Set_DE  GPIO_SetBits(GPIOC,GPIO_Pin_4);
#define Clr_DE  GPIO_ResetBits(GPIOC,GPIO_Pin_4);

// Usart1收发队列
uint8_t  m_ucUsart1RxFlag;
uint8_t  m_ucUsart1RxBuf[USART1RXBUFLEN];
uint16_t m_udUsart1RxBytes;
uint16_t m_udUsart1RxCnt;

uint8_t  m_ucUsart1TxFlag;
uint8_t  m_ucUsart1TxBuf[USART1TXBUFLEN];
uint16_t m_udUsart1TxBytes;
uint16_t m_udUsart1TxCnt;

//===============================================
uint16_t m_udUsart1WaitUs;				//收发等待时间
uint16_t m_udUsart1DelayUs;				//通讯延迟时间
uint8_t  m_ucUsart1Diag1;				//诊断信息
uint8_t  m_ucUsart1Diag2;				//诊断信息
uint8_t  m_ucUsart1Diag3;				//诊断信息
uint8_t  m_ucUsart1Diag4;				//诊断信息
uint8_t  m_ucUsart1Diag5;				//诊断信息
uint8_t  m_ucUsart1Diag6;				//诊断信息
uint8_t  m_ucUsart1MasterAddr;			//主站地址
uint8_t  m_ucUsart1LockAddr;			//被锁定的主站地址
uint8_t  m_ucUsart1LockType;			//锁定类型
uint32_t m_uwUsart1WatchDogTime;		//看门狗时间
uint8_t  m_ucUsart1MinDelay;			//最小延迟响应时间
uint16_t m_ucUsart1DeviceId;			//标识符

uint16_t m_udUsart1ProfibusErrCnt;
uint8_t  m_ucUsart1InConfigCnt;
uint8_t  m_ucUsart1OutConfigCnt;

ProfibusDpStatus  m_Usart1ProfibusDpStatus;			//ProfibusDpStatus状态结构体
//===============================================

void Usart1Init(void);
void Usart1Main(void);
void USART1_NVIC_Config(void);

void DefUsart1RX(void);
void DefUsart1TX(void);
void Usart1TxString(uint16_t udLen);

void hw_profibusdp_rx_proc(void);
//=========================================================
// 函数名称: Usart1Init
// 函数功能: 串口1初始化
// 入口参数: 无
// 出口参数: 无
//=========================================================
void Usart1Init(void)
{
	GPIO_InitTypeDef  GPIO_InitStructure;
	USART_InitTypeDef USART_InitStructure;
  
	// 初始化usart1
	USART_DeInit(USART3);	//复位串口1
	
	/* 使能 USART3 时钟*/
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);//使能外设时钟

//rx tx
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 ;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(GPIOC, &GPIO_InitStructure);
	
	
	//led 
//	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14;	
//	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;       
//	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
//	GPIO_Init(GPIOB, &GPIO_InitStructure);  //初始化PB端口
	
	/* USART3 使用IO端口配置 */    
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);    
  
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;	//浮空输入
	GPIO_Init(GPIOB, &GPIO_InitStructure);   //初始化GPIOA
	// 初始化PA口
	 
	 switch( m_ProfibusDpPar.udUsart1BaudRate )
	{	
	case 2:
		USART_InitStructure.USART_BaudRate = 9600;
		break;
	case 4:
		USART_InitStructure.USART_BaudRate = 19200;
                break
	default:
		USART_InitStructure.USART_BaudRate = 9600;
		break;
	}
	
	USART_InitStructure.USART_WordLength = USART_WordLength_9b;		// 设置数据位:9位
	USART_InitStructure.USART_StopBits = USART_StopBits_1;				// 设置停止位:1位
	USART_InitStructure.USART_Parity = USART_Parity_Even;					// 设置校验模式:奇校验		
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;	// 设置流控制
	USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;	// 设置工作模式
	USART_Init(USART3, &USART_InitStructure); 						// 配置入结构体
	
	USART_ClearITPendingBit(USART3,USART_IT_RXNE);				// 清除中断标志位	
	USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);				// 使能接收中断功能
	USART_ClearITPendingBit(USART3, USART_IT_TXE);				// 清除中断标志位
	
	USART_Cmd(USART3, ENABLE);														// 使能串口外设 
	USART1_NVIC_Config();																	// 配置相应的嵌套中断控制器
	DefUsart1RX();																				// 设置为接收状态
	
	m_ucUsart1RxFlag = false;
	m_udUsart1RxBytes = 0;
	m_udUsart1RxCnt = 0;

m_ucUsart1TxFlag = false;
	m_udUsart1TxBytes = 0;
	m_udUsart1TxCnt = 0;
	
	m_ucUsart1MasterAddr = 0xFF;			//还没有被任何主站参数化
	m_ucUsart1LockAddr = 0xFF;				//还没有被任何主站锁定	
	m_uwUsart1WatchDogTime = 0;				//看门狗时间
    m_ucUsart1MinDelay = 0;						//最小延迟响应时间
	m_ucUsart1DeviceId = 0;						//标识符
	m_udUsart1ProfibusErrCnt = 0;
	m_Usart1ProfibusDpStatus.ucPowerOn = false;
	m_Usart1ProfibusDpStatus.ucSlaveDiag = false;
	m_Usart1ProfibusDpStatus.ucSetPrm = false;
	m_Usart1ProfibusDpStatus.ucConfig = false;
	m_Usart1ProfibusDpStatus.ucDataExchange = false;
	
	m_ucUsart1Diag1 = 0;			//初始化诊断信息
	//m_ucUsart1Diag1 |= BIT0;	//该主站不存在,由主站设置
	m_ucUsart1Diag1 |= BIT1;	//未准备好进行数据交换
	//m_ucUsart1Diag1 |= BIT2;	//组态错误
	//m_ucUsart1Diag1 |= BIT3;	//该从站有扩展的诊断信息
	//m_ucUsart1Diag1 |= BIT4;	//该从站不支持所请求的功能
	//m_ucUsart1Diag1 |= BIT5;	//无效的从站响应,由主站设置,总为0
	//m_ucUsart1Diag1 |= BIT6;	//参数设置错误
	//m_ucUsart1Diag1 |= BIT7;	//该从站被不同的主站锁定
	m_ucUsart1Diag2 = 0;			//初始化诊断信息
	m_ucUsart1Diag2 |= BIT0;	//该站必须重新设置参数
	//m_ucUsart1Diag2 |= BIT1;	//静态诊断
	m_ucUsart1Diag2 |= BIT2;	//总为1
	//m_ucUsart1Diag2 |= BIT3;	//激活看门狗
	//m_ucUsart1Diag2 |= BIT4;	//Freeze锁存模式
	//m_ucUsart1Diag2 |= BIT5;	//Sync同步模式	
	//m_ucUsart1Diag2 |= BIT6;	//保留
	//m_ucUsart1Diag2 |= BIT7;	//该从站未被主站激活,由主站设置
	m_ucUsart1Diag3 = 0;			//默认为零	(诊断数据无溢出标志)
	
	switch(m_ProfibusDpPar.udUsart1BaudRate)
	{
	case 1:		//9600
		m_udUsart1DelayUs = (1000000.0 / 4800.0) * 12.0;
		break;		
	case 2:		//9600
		m_udUsart1DelayUs = (1000000.0 / 9600.0) * 12.0;
		break;
	case 3:		//14400
		m_udUsart1DelayUs = (1000000.0 / 14400.0) * 12.0;
		break;	
	case 4:		//19200
		m_udUsart1DelayUs = (1000000.0 / 19200.0) * 12.0;
		break;
	case 5:		//38400
		m_udUsart1DelayUs = (1000000.0 / 38400.0) * 12.0;
		break;	
	case 6:		//56000
		m_udUsart1DelayUs = (1000000.0 / 56000.0) * 12.0;
		break;	
	case 7:		//57600
		m_udUsart1DelayUs = (1000000.0 / 57600.0) * 12.0;
		break;	
	case 8:		//115200
		m_udUsart1DelayUs = (1000000.0 / 115200.0) * 12.0;
		break;	
	case 9:		//93750
		m_udUsart1DelayUs = (1000000.0 / 93750.0) * 12.0;
		break;
	case 10:	//187500
		m_udUsart1DelayUs = (1000000.0 / 187500.0) * 12.0;
		break;
	case 11:	//50000
		m_udUsart1DelayUs = (1000000.0 / 500000.0) * 12.0;
		break;
	default:	//9600
		m_udUsart1DelayUs = (1000000.0 / 9600.0) * 12.0;
		break;
	}
}

//=========================================================
// 函数名称: Usart1Main
// 函数功能: 串口1主程序
// 入口参数: 无
// 出口参数: 无
//=========================================================
void Usart1Main(void)
{
	if( m_ucUsart1RxFlag ){
		if(m_udUsart1WaitUs >= m_udUsart1DelayUs){
			DefUsart1TX();
			m_udUsart1WaitUs = 0;	
			m_ucUsart1RxFlag = false;	
			hw_profibusdp_rx_proc();	
			if(!m_ucUsart1TxFlag){
				DefUsart1RX();
			}
		}
	}
	if( m_ucUsart1TxFlag ){
		if(m_udUsart1WaitUs >= m_udUsart1DelayUs){
			DefUsart1RX();
			m_udUsart1WaitUs = 0;	
			m_ucUsart1TxFlag = false;	
		}
	}

//超时则重新初始化状态		
	if( m_udUsart1ProfibusErrCnt > m_uwUsart1WatchDogTime ){
		m_udUsart1ProfibusErrCnt = 0;
		//看门狗已激活
		if( m_ucUsart1Diag2 & BIT3 )	{	
			m_ucUsart1MasterAddr = 0xFF;			//还没有被任何主站参数化
			m_ucUsart1LockAddr = 0xFF;				//还没有被任何主站锁定	
			m_Usart1ProfibusDpStatus.ucPowerOn = false;
			m_Usart1ProfibusDpStatus.ucSlaveDiag = false;
			m_Usart1ProfibusDpStatus.ucSetPrm = false;
			m_Usart1ProfibusDpStatus.ucConfig = false;
			m_Usart1ProfibusDpStatus.ucDataExchange = false;
			m_ucUsart1Diag1 |= BIT1;		//未准备好进行数据交换				
			m_ucUsart1Diag1 &= ~BIT2;		//初始化组态错误标志
			m_ucUsart1Diag2 |= BIT0;		//该站必须重新设置参数
			m_ucUsart1Diag2 &= ~BIT3;		//关闭看门狗
			m_ucUsart1InConfigCnt = 0;	//初始化输入组态数量
			m_ucUsart1OutConfigCnt = 0;	//初始化输出组态数量
		}
	}	
}

//=========================================================
// 函数名称: USART1_NVIC_Config
// 函数功能: 配置串口1中断
// 入口参数: 无
// 出口参数: 无
//=========================================================
void USART1_NVIC_Config(void)
{
	NVIC_InitTypeDef USART_NVIC_InitStructuer;
	
	USART_NVIC_InitStructuer.NVIC_IRQChannel = USART3_IRQn;
  USART_NVIC_InitStructuer.NVIC_IRQChannelPreemptionPriority = 0;
  USART_NVIC_InitStructuer.NVIC_IRQChannelSubPriority = 1;
  USART_NVIC_InitStructuer.NVIC_IRQChannelCmd = ENABLE;	
	NVIC_Init( &USART_NVIC_InitStructuer );
}

//=========================================================
// 函数名称: USART3_IRQHandler
// 函数功能: 串口中断
// 入口参数: 无
// 出口参数: 无
//=========================================================
void USART3_IRQHandler(void)
{		
	if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET)    	// 接收检测
	{			
		if( m_udUsart1RxCnt >= USART1RXBUFLEN ) m_udUsart1RxCnt = 0;
		m_ucUsart1RxBuf[m_udUsart1RxCnt++] = USART_ReceiveData(USART3);
		m_udUsart1WaitUs = 0;
		m_ucUsart1RxFlag = true;
		USART_ClearITPendingBit(USART3, USART_IT_RXNE);					// 清除中断标志位
	}
	else if(USART_GetITStatus(USART3, USART_IT_TXE) != RESET)	// 发送检测
	{		
		if( m_udUsart1TxCnt < m_udUsart1TxBytes ){
			USART3->DR = m_ucUsart1TxBuf[m_udUsart1TxCnt++];
		}
		else{
			USART_ITConfig(USART3, USART_IT_TXE, DISABLE);				// 使能发送中断功能
			m_udUsart1TxCnt = 0;
			m_udUsart1TxBytes = 0;
		}
		m_udUsart1WaitUs = 0;
		USART_ClearITPendingBit(USART3, USART_IT_TXE);					// 清除中断标志位
	}
}

//=========================================================
// 函数名称：DefUsart1RX
// 函数功能：通讯口1定义为接收
// 入口参数：无
// 出口参数：无
//=========================================================
void DefUsart1RX(void)
{	
	//DelayUs(5000);
	Clr_DE;
	Clr_RE; 
}

//=========================================================
// 函数名称：DefUsart1TX
// 函数功能：通讯口1定义为发送
// 入口参数：无
// 出口参数：无
//=========================================================
void DefUsart1TX(void)
{
	Set_DE;
	Set_RE;
	//DelayUs(5000);
}

//=========================================================
// 函数名称：Usart1TxString
// 函数功能：发送字符串
// 入口参数：ucLen发送长度
// 出口参数：无
//=========================================================
void Usart1TxString(uint16_t udLen)
{	
	DefUsart1TX();
	m_ucUsart1TxFlag = true;
	m_udUsart1TxBytes = udLen;
	m_udUsart1TxCnt = 0;
	USART3->DR = m_ucUsart1TxBuf[m_udUsart1TxCnt++];	
	USART_ITConfig(USART3, USART_IT_TXE, ENABLE);					// 使能发送中断功能		
}

//=========================================================
// END FILE
//=========================================================

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3 个回答

出出啊 2022-05-30

致男人们：劝说是不会有成果的。 —— 《单向街》

yc985055 2022-06-06

这家伙很懒，什么也没写！

下面是裸奔的程序. 逻辑分析仪中它回复的字节间隔就是100us左右, 相当于1个停止位! rtthread中有没有办法去掉起始位或停止位, 我去其一试试