STM32的485最简单例程.docx

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1、485最基本的半双工通信配置采用STM32F103ZET6串口3连接485芯片通信口，485芯片的A,B通过485转串口模块与电脑相连，完成在串口软件上输入输出功能。串口3，配置函数：void USART3_Config(void)GPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure; NVIC_InitTypeDef NVIC_InitStructure;RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE

2、);RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);/ USART3_TX - PB10 , USART3_RX -PB11GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin =

3、 GPIO_Pin_11; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStructure);USART_InitStructure.USART_BaudRate = 115200; / 1200; USART_InitStructure.USART_WordLength = USART_WordLength_8b;USART_InitStructure.USART_StopBi

4、ts = USART_StopBits_1;USART_InitStructure.USART_Parity = USART_Parity_No; /USART_Parity_Even;USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;USART_Init(USART3, &USART_InitStructure); NVIC_PriorityGroupConfi

5、g(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);#ifdef PDU_USART3_DMAUSART_ITConfig(U

6、SART3, USART_IT_IDLE, ENABLE);#else/ Enable the USART Receive interrupt: this interrupt is generated when the /USART3 receive data register is not empty/USART_ClearITPendingBit(USART3, USART_IT_TC);USART_ClearFlag(USART3,USART_FLAG_TC);USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);USART_ITConfig(USA

7、RT3, USART_IT_TC, ENABLE);/USART_ITConfig(USART3, USART_IT_TXE, ENABLE);USART_ClearFlag(USART3,USART_FLAG_TC);#endif USART_Cmd(USART3, ENABLE);USART_ClearFlag(USART3,USART_FLAG_TC);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOE | RCC_APB2Periph_AFIO, ENABLE);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15; G

8、PIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOE, &GPIO_InitStructure);RS_485_TX_ENABLE();PUTCHAR_PROTOTYPE /* Place your implementation of fputc here */ /* e.g. write a character to the USART */ USART_SendData(USART3, (uint8_t) ch);/US

9、ART_SendData(USART1,(uint8_t)ch); /* Loop until the end of transmission */ /while (USART_GetFlagStatus(USART1, USART_FLAG_TC) = RESET)while (USART_GetFlagStatus(USART3, USART_FLAG_TXE) = RESET) return ch;中断函数：void USART3_IRQHandler(void)if(USART_GetITStatus(USART3, USART_IT_IDLE) != RESET) USART_Cle

10、arITPendingBit(USART3, USART_IT_IDLE);if(USART_GetFlagStatus(USART3, USART_FLAG_RXNE)!=RESET) USART_ClearFlag(USART3,USART_FLAG_RXNE); TIM3_Init(1000, 7200); BLUE_ON(); if(cnt=32) cnt=0; else datacnt=USART_ReceiveData(USART3); cnt+; if (USART_GetITStatus(USART3, USART_IT_TC) != RESET) |(USART_GetITS

11、tatus(USART3, USART_IT_TXE) != RESET) )USART_ClearITPendingBit(USART3, USART_IT_TC);USART_ClearITPendingBit(USART3, USART_IT_TXE);/ USART_SendData(USART3, 0XFFFF);void TIM3_IRQHandler(void) if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) TIM_ClearITPendingBit(TIM3, TIM_IT_Update);TIM3_DeInit(); B

12、LUE_OFF();/ printf(rn %x,cnt); cnt=0;static void NVIC_TIM3Configuration(void) NVIC_InitTypeDef NVIC_InitStructure; /* Set the Vector Table base address at 0x08000000 */ /NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0000); /* Enable the TIM3 gloabal Interrupt */ NVIC_InitStructure.NVIC_IRQChannel = TIM3

13、_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);定时器：void TIM3_Init(uint16_t tcon, uint16_t psc) TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; / TIM3 clo

14、ck enable RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);/ reset timerTIM_DeInit(TIM3); / Time base configuration/ value to reload TIM_TimeBaseStructure.TIM_Period = (tcon - 1); / pre-scaler value against system clock TIM_TimeBaseStructure.TIM_Prescaler = (psc - 1); / scaler value against syste

15、m clock TIM_TimeBaseStructure.TIM_ClockDivision = 0; / counting mode TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; / init timer TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); / Clear TIM3 update pending flag TIM_ClearITPendingBit(TIM3, TIM_IT_Update); / TIM IT enable of over-counting

16、TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE); / config timers interruption function NVIC_TIM3Configuration();/ Enable TIM3 counter TIM_Cmd(TIM3, ENABLE);void TIM3_DeInit(void)/ Disable TIM3 counter TIM_Cmd(TIM3, DISABLE);/ Reset timerTIM_DeInit(TIM3);/ Disable TIM3 clock RCC_APB1PeriphClockCmd(RCC_APB1

17、Periph_TIM3, DISABLE);/tim3_stat = 0x00;主函数：#ifdef _GNF_#ifdef _GNUC_ /* With GCC/RAISONANCE, small printf (option LD Linker-Libraries-Small printf set to Yes) calls _io_putchar() */ #define PUTCHAR_PROTOTYPE int _io_putchar(int ch)#else #define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)#endif /*

18、_GNUC_ */#endif /* _GNF_ */void Delay(uint32_t tick) while(tick-)/* Private function prototypes -*/extern unsigned char datasize;extern volatile unsigned char cnt;* Function Name : main* Description : Main program* Input : None* Output : None* Return : None* Attention : Noneint main(void) /*USART co

19、nfiguration*/ USART3_Config(); RED_ON(); BLUE_ON(); GREEN_ON(); Delay(100000); BLUE_OFF(); RED_OFF(); GREEN_OFF();/* Infinite loop */while (1)uint8_t i=0;RS_485_TX_ENABLE(); printf(rn up up day! );for(i=0;i50;i+) GREEN_ON(); Delay(500000); GREEN_OFF(); Delay(500000); RS_485_RX_ENABLE();while(data0=0x00) RED_ON(); Delay(500000); RED_OFF(); Delay(500000);memset(data,0,size);第 10 页