AnsweredAssumed Answered

stm32f4discovery problem with hc-05 bluetooth module

Question asked by fitdra.reza on Mar 17, 2014
Latest reply on Mar 18, 2014 by Andrew Neil
I'm having a problem with my usart communication between stm32f4 and hc-05 bluetooth module. I'm trying to configure the AT command of HC-05 using the stm32 board and i'm checking the response using the USB serial module and serial monitor.  But i'm not getting any response. I'm using USART3. Can you please tell me if you find any problem in my pin configuration or my code. thanks
This is my pin configuration:
stm32 3v pin ---------> hc-05 vcc and key pin
stm32 tx --------------> hc-05 rx pin
hc-05 tx ---------------> USB serial rx pin (to check the response on serial monitor)

this is the code that i'm using:

#include "stm32f4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_usart.h"
#include <string.h>
#include <stdio.h>

GPIO_InitTypeDef              GPIO_InitStructure;
USART_InitTypeDef             USART_InitStructure;

void USART_put(USART_TypeDef* USARTx, volatile char *s){

        // wait until data register is empty
        while( !(USARTx->SR & 0x00000040) );
        USART_SendData(USARTx, *s);
        while(USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)

void GPIO_USART_Configuration(void){
     RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
     /* Configure USART Tx as alternate function  */
       GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
       GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
       GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

       GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
       GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
       GPIO_Init(GPIOC, &GPIO_InitStructure);

     /* Connect PXx to USARTx_Tx*/
       GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_USART3);

 void USART3_Configuration(void)

         USART_InitStructure.USART_BaudRate = 38400;
         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_Tx;

         USART_Init(USART3, &USART_InitStructure);
         USART_Cmd(USART3, ENABLE); // enable USART2
void usart_inisialisasi()

int main(void) {


USART_put(USART3, "AT\r\n");