STM32F427的TP8485芯片RS485和PC通信源程序 -

#include "stm32f4xx.h"
#include "stm32f4xx_usart.h"
uint8_t rx_flag=0;
uint8_t rx_buff[100]={0x00,0x00};
uint8_t i=0,j=0;
uint8_t n=5;
void USART_INIT(void);
void nvic_configuration(void);
int main(void)
{
USART_INIT();
GPIO_SetBits(GPIOA, GPIO_Pin_6);
USART_SendData(USART2, 66);
while(USART_GetFlagStatus(USART2,USART_FLAG_TC)==RESET);
USART_SendData(USART2, 67);
while(USART_GetFlagStatus(USART2,USART_FLAG_TC)==RESET);
GPIO_ResetBits(GPIOA, GPIO_Pin_6);
while(1)
{
if(rx_flag==1)
{
rx_buff[i++]=USART_ReceiveData(USART2);
rx_flag=0;
}
if(i==n)
{
GPIO_SetBits(GPIOA, GPIO_Pin_6);
i=0;
for(j=0;j<n;j++)
{
USART_SendData(USART2, rx_buff[j]);
while(USART_GetFlagStatus(USART2, USART_FLAG_TC)==RESET);
}
GPIO_ResetBits(GPIOA, GPIO_Pin_6);
}
}
}
void USART_INIT(void)
{
// GPIO initiallize
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHB1PeriphClockCmd (RCC_AHB1Periph_GPIOA ,ENABLE); //使能外设时钟AHB1
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; // A6 control singal
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; //实际上就是推挽输出
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_ResetBits(GPIOA, GPIO_Pin_6);
GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_USART2); //GPIOA2复用为USART2
GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_USART2); //GPIOA3复用为USART2
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 |GPIO_Pin_3 ; //Tx and Rx
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //alternate function
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //low rate
GPIO_Init(GPIOA, &GPIO_InitStructure);
////USART initiallize
USART_InitTypeDef usart_2_initstructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);//使能USART2时钟挂载在APB1外设时钟上
usart_2_initstructure.USART_BaudRate=9600;
usart_2_initstructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
usart_2_initstructure.USART_Mode=USART_Mode_Rx |USART_Mode_Tx;
usart_2_initstructure.USART_Parity=USART_Parity_No;
usart_2_initstructure.USART_StopBits=USART_StopBits_1;
usart_2_initstructure.USART_WordLength=USART_WordLength_8b;
USART_Init(USART2, &usart_2_initstructure);
USART_Cmd(USART2, ENABLE); //使能串口2
//some flags and IT
USART_ClearFlag(USART2, USART_FLAG_TC); //clear transmit flag
nvic_configuration();
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//开启相关中断
}
//内嵌中断向量控制器config
void nvic_configuration()
{
//NVIC config and initiallize
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel=USART2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE ;
NVIC_Init(&NVIC_InitStructure);
}
void USART2_IRQHandler()
{
if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
{
// rx_buff[i++]=USART_ReceiveData(USART2);
rx_flag=1;
USART_ClearFlag(USART2, USART_FLAG_RXNE);
}
}

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