stm32f103使用usart1实现2.5M通信

247470035 · 发表于 2019-10-30 17:12:22

如题，stm32f103使用usart1实现2.5M通信
外部与MAX3485通信，实测大于348000波特率时就会出现误码，怎么达到2.5M的比特率通信
已知，串口usart1理论最大可以达到4.5M,MAX3485通信可以到达10M，小于等于348000波特率是通信正常
基本判断，软件大概率没有问题（基于实测，小于等于348000波特率是通信正常），硬件使用的是MAX3485，直接与stm32f103相连，会不会是EMC问题或者布线问题？

#include "usart1.h"

extern u8 USART1_RX_BEGIN;
extern u8 USART1_RX_BEGIN_NUMBER;
extern u8 USART1_RX_END;
extern u8 USART_RX_BUF[6];

extern u16 USART_RX_STA;

void usart1_init(void)
{
GPIO_InitTypeDef GPIO_InitStruct;
USART_InitTypeDef USART_InitStruct;
NVIC_InitTypeDef NVIC_InitStruct;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStruct);

GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10;
GPIO_Init(GPIOA, &GPIO_InitStruct);

USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStruct.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
USART_InitStruct.USART_Parity = USART_Parity_No;
USART_InitStruct.USART_StopBits = USART_StopBits_1;
USART_InitStruct.USART_WordLength = USART_WordLength_8b;
// USART_InitStruct.USART_BaudRate = 384000;
USART_Init(USART1, &USART_InitStruct);

USART1->BRR = 0x1d; //波特率设置为2482758.62

NVIC_InitStruct.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
NVIC_Init(&NVIC_InitStruct);

USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_Cmd(USART1, ENABLE);
}

void USART1_IRQHandler(void)
{
u8 Res;

if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) //接收中断
{

Res = USART_ReceiveData(USART1); //读取接收到的数据

if(Res == 0x02) //当数据接收到0x02时开始接受，一共接受6个数据
{
USART1_RX_BEGIN = 1;
}

if(USART1_RX_BEGIN == 1)
{
USART_RX_BUF[USART1_RX_BEGIN_NUMBER] = Res;
USART1_RX_BEGIN_NUMBER++;

if(USART1_RX_BEGIN_NUMBER == 6)
{
USART1_RX_BEGIN_NUMBER = 0;
USART1_RX_BEGIN = 0;
USART1_RX_END = 1;
}
}
}

}