keil5 rs485发送数据函数
时间: 2023-07-29 15:07:02 浏览: 90
以下是在Keil5中使用RS485发送数据的示例代码:
```c
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "stm32f4xx.h"
#define RS485_USART USART1
#define RS485_TX_PIN GPIO_Pin_9
#define RS485_RX_PIN GPIO_Pin_10
#define RS485_TX_GPIO_PORT GPIOA
#define RS485_RX_GPIO_PORT GPIOA
#define RS485_GPIO_AF GPIO_AF_USART1
void rs485_init(void)
{
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
GPIO_InitStructure.GPIO_Pin = RS485_TX_PIN | RS485_RX_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(RS485_TX_GPIO_PORT, &GPIO_InitStructure);
GPIO_PinAFConfig(RS485_TX_GPIO_PORT, GPIO_PinSource9, RS485_GPIO_AF);
GPIO_PinAFConfig(RS485_RX_GPIO_PORT, GPIO_PinSource10, RS485_GPIO_AF);
USART_InitStructure.USART_BaudRate = 9600;
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;
USART_Init(RS485_USART, &USART_InitStructure);
USART_Cmd(RS485_USART, ENABLE);
}
void rs485_send(uint8_t *data, uint16_t len)
{
GPIO_SetBits(RS485_TX_GPIO_PORT, RS485_TX_PIN);
USART_SendData(RS485_USART, *data++);
while (--len) {
while (USART_GetFlagStatus(RS485_USART, USART_FLAG_TXE) == RESET);
USART_SendData(RS485_USART, *data++);
}
while (USART_GetFlagStatus(RS485_USART, USART_FLAG_TC) == RESET);
GPIO_ResetBits(RS485_TX_GPIO_PORT, RS485_TX_PIN);
}
```
首先,需要定义RS485使用的USART和GPIO引脚。在`rs485_init()`函数中初始化USART和GPIO。在`rs485_send()`函数中,使用GPIO引脚控制RS485芯片发送模式和接收模式,并通过USART发送数据。需要注意的是,在每次发送数据后需要等待数据发送完成,否则可能会出现数据发送不完整的情况。
以上代码仅供参考,具体实现方式可能会因芯片型号和连接方式的不同而有所不同。