stm32f100c8 and ublox leon g100 USART communication

[rasimoguzturk]

Posted on October 04, 2012 at 13:20

hi all,i am recently working on a project that sending AT command to gsm module from stm32f100c8  via usart and receiving response with interrupt but i am very confused about usart interfaces.i cant receive response from gsm module.i am using stm32vl discovery and ublox leon g100 gsm module usart1 and usart3 and terminal.It sends me back same string.i send ''AT'' and i want to get ''OK'' response from module.please help where am i wrong?here is my code :

/*----------------------------------------------*/

/*----------------------------------------------*/

#include ''stm32f10x.h''

#include ''stdio.h''

#include ''string.h''

/*----------------------------------------------*/

/*---------function prototypes------------------*/

void RCC_Configuration(void);

void GPIO_Configuration(void);

void NVIC_Configuration(void);

void USART_Configuration(void);

void ResetModule(void);

void USART_SendCommand(unsigned char *s);

/*------------------------------------------------*/

/*-------------global variables-------------------*/

unsigned char command[]=''AT\0\r\n'';

char response[50];

int res_index=0;

unsigned char r;

/*----------------------------------------------*/

/*----------RCC configurations------------------*/

void RCC_Configuration(void){

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

}

/*----------------------------------------------*/

/*----------GPIO configurations------------------*/

void GPIO_Configuration(void){

GPIO_InitTypeDef GPIO_InitStructure;

/* Configuring USART1_Tx as 'alternate function push-pull' */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configuring USART1_Rx as 'input floating' */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configuring USART3_Tx as 'alternate function push-pull' */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOB, &GPIO_InitStructure);

/* Configuring USART3_Rx as 'input floating' */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOB, &GPIO_InitStructure);

/* reset the module*/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_Init(GPIOB, &GPIO_InitStructure );

}

/*----------------------------------------------*/

/*----------USART configurations----------------*/

void USART_Configuration(void){

USART_InitTypeDef USART_InitStructure;

USART_InitStructure.USART_BaudRate = 9600;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;

USART_InitStructure.USART_StopBits = USART_StopBits_1;

USART_InitStructure.USART_Parity = USART_Parity_No;

USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

USART_Init(USART1, &USART_InitStructure);

USART_Cmd(USART1, ENABLE);

USART_Init(USART3, &USART_InitStructure);

USART_Cmd(USART3, ENABLE);

USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);

}

/*----------------------------------------------*/

/*----------NVIC configurations-----------------*/

void NVIC_Configuration(void){

NVIC_InitTypeDef NVIC_InitStructure;

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

/*----------------------------------------------*/

/*----------RESET module-----------*/

void ResetModule(void){

long int n;

//reset 

GPIO_SetBits(GPIOB,GPIO_Pin_13);

for(n = 0;n < 10000000;n++); 

GPIO_ResetBits(GPIOB,GPIO_Pin_13);

for(n = 0;n < 30000000;n++);

//power

GPIO_SetBits(GPIOB,GPIO_Pin_12);

for(n = 0;n < 10000000;n++);

GPIO_ResetBits(GPIOB,GPIO_Pin_12);

}

/*----------------------------------------------*/

/*----------Main function-----------------------*/

int main(){

RCC_Configuration();

GPIO_Configuration();

USART_Configuration();

NVIC_Configuration();

ResetModule();

USART_SendCommand(command);

while(1){

}

}

/*----------------------------------------------*/

/*----------Send command------------------------*/

void USART_SendCommand(unsigned char *s)

{

while(*s)

{

//while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

//USART_SendData(USART1, *s);

while(USART_GetFlagStatus(USART3, USART_FLAG_TXE) == RESET);

USART_SendData(USART3, *s++);

}

}

/*----------------------------------------------*/

/*----------Receive character from USART3-------*/

void USART3_IRQHandler(void){ 

r=USART_ReceiveData(USART3);

response[res_index]=r;

res_index++;

}

/*----------------------------------------------*/

/*--------------------------------------------------------------------------------------------*/

/*--------------------------------------------------------------------------------------------*/

/*--------------------------------------------------------------------------------------------*/

/*--------------------------------------------------------------------------------------------*/

[frankmeyer9]

Posted on October 04, 2012 at 14:08

I guess this is the common HSE_VALUE problem.

Open your stm32f10x.h header file, and search for the definition of this value (HSE_VALUE), which defines the frequency of the ext. quartz oscillator. It will probably be 25.000.000, which is not correct for the stm32vl_discovery - it has a 8MHz quartz (8.000.000). Change it either directly, or (better), add the proper definitions to your build options.

[frankmeyer9]

Posted on October 04, 2012 at 14:08

double post, forum software crashed yet again ...

[Andrew Neil]

Posted on October 04, 2012 at 14:37

''

It sends me back same string. i send 'AT''' That's called Echo - you control it with the ATE command. Before writing code on a microcontroller, you should explore these things ''manually'' with a terminal program...

[rasimoguzturk]

Posted on October 04, 2012 at 14:53

@ fm -> my external board has 16000000 clock i have already changed HSE value it did not work:(..

@neil when i send ''ATE'' command it sends me back only ''AT'' as a response.my focus is first send AT and recieve OK as response

[Tesla DeLorean]

Posted on October 04, 2012 at 17:10

unsigned char command[]=''AT\0\r\n'';

The NUL here is problematic.

[rasimoguzturk]

Posted on October 04, 2012 at 19:09i tried both scenario,''AT\r\r'',''AT'',''AT\0''etc..also i tried ''ATE0''..when i send ''ATE0'' it sends me back only ''AT'',but for other any strings it returns same string..ex:send(''AT\r\n'') response:''AT''send(''ATE0\r\n'')response: ''AT''send(''helloworld\r\n'')response: helloworld..:(

[Tesla DeLorean]

Posted on October 04, 2012 at 19:26

Sounds a lot like you've got it wired up wrong. Either that, or how you're making the determination about the data being received.

The code doesn't look dysfunctional, suggest you work on your debugging/troubleshooting skills.

[rasimoguzturk]

Posted on October 04, 2012 at 19:45

i think so..i cannot test the module whether working properly or not and i spent too much time with the code searching any missed thing.

[Andrew Neil]

Posted on October 05, 2012 at 00:03

''i tried both scenario,''AT\r\r'',''AT'',''AT\0''etc..''

But, again, you need to ensure that you can do this manually from a terminal

before

  you start messing with microcontroller code!