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stm32VL UART problem

marwen_azouzi
Associate II
Posted on May 03, 2012 at 03:14

Hi

i have to communicate with modem using uart via AT command

my pb is when i send the first command and receive the reponse i can't send the next AT using uart

i can post my code if any one can help me 

#uart #adc-stm32-discovery
11 REPLIES 11
marwen_azouzi
Associate II
Posted on May 03, 2012 at 03:28

Posted on May 03, 2012 at 04:21

#include ''stm32f10x.h''
#include ''STM32vldiscovery.h''
#include ''stm32f10x_gpio.h''
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
void SendString(char *s)
{
while(*s)
{
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
USART_SendData(USART1, *s++);
}
}
int main(void)
{
USART_InitTypeDef USART_InitStructure;
/* System Clocks Configuration */
RCC_Configuration();
/* NVIC configuration */
//NVIC_Configuration();
/* Configure the GPIO ports */ 
GPIO_Configuration();
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 9600 baud 
- Word Length = 8 Bits
- Two Stop Bit
- Odd parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
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_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init( USART1,&USART_InitStructure);
/* You might want some delays between these,
I'm just illustrating how to transmit to the USART
with a subroutine */
SendString(''AT?
'');
SendString(''ATB
'');
while(1)
{
}
}
void RCC_Configuration(void)
{
/* Enable GPIO clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
/* Enable USART2 Clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
/* Setup the microcontroller system. Initialize the Embedded Flash Interface, 
initialize the PLL and update the SystemFrequency variable. */
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure USART1 Rx as input floating */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* Configure 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);
}
#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

'', file, line) */
/* Infinite loop */
while (1)
{
}
}
#endif

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marwen_azouzi
Associate II
Posted on May 04, 2012 at 02:37

thx using fct to send is an easy way 

in your opinion  for the reception I had to use  interrupt or just polling mode 

i must compare the Inbuffer to send other AT command
Posted on May 04, 2012 at 16:24

in your opinion  for the reception I had to use  interrupt or just polling mode 

 

i must compare the Inbuffer to send other AT command.

There are a number of ways of doing it, I personally use interrupts, and FIFO (ring) buffers on both the receive and transmit side.
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marwen_azouzi
Associate II
Posted on May 04, 2012 at 18:22

One little thing in case of using interrupt after receiving data from modem i must compare the reponse with the true one

so i have to clear Rxbuffer after each reception ? 
Posted on May 04, 2012 at 18:58

One little thing in case of using interrupt after receiving data from modem i must compare the reponse with the true one so i have to clear Rxbuffer after each reception ?

 

In a robust solution, you'll need to parse the responses, different modems respond differently, and you might get unexpected responses. Typically you'd be looking for ''OK'', ''ERROR'', ''NO CARRIER'', etc.
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marwen_azouzi
Associate II
Posted on May 09, 2012 at 00:57

Hi again

I use for the comparaison the function ''buffercmp'' which compaire 2 buffer as result ''FAILED'' or ''PASSED'' i want a way which after the comparaison to clear the Rxbuffer  
Posted on May 09, 2012 at 02:31

I use for the comparaison the function ''buffercmp'' which compaire 2 buffer as result ''FAILED'' or ''PASSED'' i want a way which after the comparaison to clear the Rxbuffer

While I think this is a rather sloppy approach, what you're suggesting would look like this :

// Receive enough to evaluate...
if (Buffercmp(RxBuffer, ''ERROR'', RxCounter) == PASSED)
puts(''Modem returned ERROR!'');
RxCounter = 0; // Clear RxBuffer to beginning

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marwen_azouzi
Associate II
Posted on May 09, 2012 at 04:18

which the best way so in your opinion

i have multiple reception for each reception i must compare and send the suitable command