Question
USART issue
Posted on October 05, 2013 at 21:02
I am getting faulty data while using USART. This is the program that i have written but what i get is the garbage values.
/* Includes */#include ''stm32f4xx.h''#include ''stm32f4xx_gpio.h''#include ''stm32f4xx_tim.h''#include ''stm32f4xx_usart.h''/* Private macro *//* Private variables *//* Private function prototypes */void Delay(__IO uint32_t nCount);/* Private functions */GPIO_InitTypeDef GPIO_InitStructure;TIM_TimeBaseInitTypeDef TIM_InitStruct;NVIC_InitTypeDef NVIC_InitStructure;USART_InitTypeDef USART_InitStructure;/** **=========================================================================== ** ** Abstract: main program ** **=========================================================================== */int i;char b;void Delay(__IO uint32_t nCount){ while(nCount--) { }}int main(void){ RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE); /* GPIOA clock enable */ RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); /* GPIOA Configuration: USART3 TX on PA2 */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11 | GPIO_Pin_10; 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_NOPULL ; GPIO_Init(GPIOB, &GPIO_InitStructure); /* Connect USART3 pins to AF2 */ // TX = PA2 GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3); GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3); USART_InitStructure.USART_BaudRate = 115200; 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(USART3, &USART_InitStructure); USART_ITConfig(USART3, USART_IT_RXNE, ENABLE); // enable the USART1 receive interrupt NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn; // we want to configure the USART1 interrupts NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;// this sets the priority group of the USART1 interrupts NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; // this sets the subpriority inside the group NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; // the USART1 interrupts are globally enabled NVIC_Init(&NVIC_InitStructure); // the properties are passed to the NVIC_Init function which takes care of the low level stuff USART_Cmd(USART3, ENABLE); // enable USART3 /* Infinite loop */ while (1) { }}void USART3_IRQHandler(void){ // check if the USART1 receive interrupt flag was set USART_ClearFlag(USART3, USART_FLAG_RXNE); b = USART_ReceiveData(USART3); USART_SendData(USART3, b); USART_ClearITPendingBit(USART3, USART_IT_RXNE);}