Hi guys .. i am not getting proper output on HT for transmission of character from STM32f4xx discovery board . please let me know where i am wrong. I am using Teraterm HT for Serial Communication on 9600 baudrate(8 bit char , 1 stop bit, no parity).
#include "stm32f4xx.h" #include "stm32f4xx_gpio.h" #include <stm32f4xx_usart.h> #include "stm32f4xx_rcc.h" #include "my_print.h" #include "misc.h"
void Delay(__IO uint32_t nCount) { while(nCount--) { } }
void init_USART1(uint32_t baudrate){
// USART1........................................................
GPIO_InitTypeDef GPIO_InitStruct; // this is for the GPIO pins used as TX and RX USART_InitTypeDef USART_InitStruct; // this is for the USART1 initilization USART_ClockInitTypeDef USART_ClockInitStruct; //NVIC_InitTypeDef NVIC_InitStructure;
/* enable APB2 peripheral clock for USART1 * note that only USART1 and USART6 are connected to APB2 * the other USARTs are connected to APB1 */ RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 , ENABLE);
/* enable the peripheral clock for the pins used by * USART1, PB6 for TX and PB7 for RX */ RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
/* This sequence sets up the TX and RX pins * so they work correctly with the USART1 peripheral */ GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9 ; // Pins 9 (TX) are used GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF; // the pins are configured as alternate function so the USART peripheral has access to them GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz; // this defines the IO speed and has nothing to do with the baudrate! GPIO_InitStruct.GPIO_OType = GPIO_OType_PP; // this defines the output type as push pull mode (as opposed to open drain) GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL; // this activates the pullup resistors on the IO pins GPIO_Init(GPIOA, &GPIO_InitStruct); // now all the values are passed to the GPIO_Init() function which sets the GPIO registers
/* The RX and TX pins are now connected to their AF * so that the USART1 can take over control of the * pins */ GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1); // //GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);
/* Now the USART_InitStruct is used to define the * properties of USART1 */ USART_InitStruct.USART_BaudRate = baudrate; // the baudrate is set to the value we passed into this init function USART_InitStruct.USART_WordLength = USART_WordLength_8b;// we want the data frame size to be 8 bits (standard) USART_InitStruct.USART_StopBits = USART_StopBits_1; // we want 1 stop bit (standard) USART_InitStruct.USART_Parity = USART_Parity_No; // we don't want a parity bit (standard) USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None; // we don't want flow control (standard) USART_InitStruct.USART_Mode = USART_Mode_Tx; // we want to enable the transmitter and the receiver
USART_Init(USART1, &USART_InitStruct); // again all the properties are passed to the USART_Init function which takes care of all the bit setting
// finally this enables the complete USART1 peripheral USART_Cmd(USART1, ENABLE);
}
void USART_puts(USART_TypeDef* USARTx, volatile char *s){
while(*s){ // wait until data register is empty while( !(USARTx->SR & 0x00000040) ); USART_SendData(USARTx, *s); s++; } }
//..........................
#include "main.h"
int main(void) { // SystemCoreClockUpdate(); init_USART1(9600); // initialize USART1 @ 9600 baud
USART_puts(USART1, "******A"); while (1){ /* * You can do whatever you want in here */ } }