stm32 UART communcation problems - Page 1
Forum section: electronics / general

author: pranay singh
author_rank: Newbie
timestamp: March 28, 2014, 06:52:11 am
content: Hello,I'm using a stm32f100RB microcontroller, I'm having 2 issues1)When i plug in the board via USB, after installing the drivers succesfully, in device manager the board is shown under disk drives instead of ports. How do i get it under ports ? My computer is recognizing the board as a mass storage device. Although I'm having no problem burning codes via the IAR embedded toolchain and everything is working fine. However Im having a big issue trying to establish serial communication as i'm unable to specify a port no.2)To get around this i tried using a USB to RS232 converter via a MAX232 for the voltage conversions. It's picking up garbage value when i try to program it and after that the terminal dosent show anything.This is the Code ==>>#include "stm32f10x.h"#include "stm32f10x_usart.h"//Structure initializationGPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;void Delay(__IO uint32_t nCount);int putchar(__IO uint32_t c){while (USART_GetFlagStatus(USART1 , USART_FLAG_TXE) == RESET);{USART1->DR = (c & 0xff);}return c;}int main(void){RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |RCC_APB2Periph_GPIOB |RCC_APB2Periph_GPIOD |RCC_APB2Periph_GPIOE, ENABLE);GPIO_StructInit(&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;GPIO_Init(GPIOB, &GPIO_InitStructure);GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_Init(GPIOE, &GPIO_InitStructure);RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |RCC_APB2Periph_GPIOB |RCC_APB2Periph_GPIOD |RCC_APB2Periph_GPIOE, DISABLE);//Clock enableRCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC |RCC_APB2Periph_GPIOA |RCC_APB2Periph_USART1 |RCC_APB2Periph_AFIO , ENABLE);//LED pin initializationGPIO_StructInit(&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz ;GPIO_Init(GPIOC, &GPIO_InitStructure);// Button pin initializationGPIO_StructInit(&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_Init(GPIOA, &GPIO_InitStructure);//Tx initializationGPIO_StructInit(&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz ;GPIO_Init(GPIOA, &GPIO_InitStructure);//Rx initializationGPIO_StructInit(&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_Init(GPIOA, &GPIO_InitStructure);//USART1 initializationUSART_StructInit (& USART_InitStructure);USART_InitStructure.USART_BaudRate = 115200;USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;USART_InitStructure.USART_WordLength = USART_WordLength_8b; //Word Length = 8 BitsUSART_InitStructure.USART_StopBits = USART_StopBits_1; //Two Stop BitUSART_InitStructure.USART_Parity = USART_Parity_No ; //No parityUSART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;USART_Init(USART1 ,& USART_InitStructure);USART_Cmd(USART1 , ENABLE);int a;while (1){putchar(a);USART_SendData(USART1,a); //trying both commands but none of them seem to work}}/*** @brief Inserts a delay time.* @param nCount: specifies the delay time length.* @retval None*/void Delay(__IO uint32_t nCount){for(; nCount != 0; nCount--);}#ifdef USE_FULL_ASSERT/*** @brief Reports the name of the source file and the source line number* where the assert_param error has occurred.* @param file: pointer to the source file name* @param line: assert_param error line source number* @retval None*/void assert_failed(uint8_t* file, uint32_t line){/* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* Infinite loop */while (1){}}#endif/*** @}*//*** @}*//******************* (C) COPYRIGHT 2010 STMicroelectronics *****END OF FILE****/