STM32L communication between 2 USART

[kitjazax]

Posted on March 25, 2015 at 17:39

Hello all,

I 'm novice and using STM32L152RE to do a communication between 2 USARTs I use USART2 for recieving GPS Data and I would like to echo all recievied data without parsing on PC Terminal by using USART3 but I  only got a unreadable character return. Can someone please help me with it? Thank you

[Tesla DeLorean]

Posted on March 25, 2015 at 17:58

The STM32 USART's don't output at RS232 compatible voltages.

Why don't you start by describing the board you're using, and the connections/pins being used. The GPS receiver used, and the baud rates at play. At least this way someone could mash up a simple example. Post the code that doesn't work now. Review other code

https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/USART%20Problem%20with%20nucleo%20L152&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&currentviews=123

[kitjazax]

Posted on March 25, 2015 at 18:58

thanks for your advise I connect the GPS reciever with 5V power supply and use 2 cables for connecting their tx and rx pins to uC(Nucleo l152RE ) here is my code 

GPS reciever is Maestro A-2200 and working as 4800 Buad #include ''main.h'' //**************************************************************************** void RCC_Configuration(void) {   /* USART2 and 3 clock enable */   RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2 | RCC_APB1Periph_USART3, ENABLE);   /* GPIOA clock enable */   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB, ENABLE); } //**************************************************************************** void GPIO_Configuration(void) {   GPIO_InitTypeDef GPIO_InitStructure;   /* GPIO Configuration */   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;   GPIO_Init(GPIOA, &GPIO_InitStructure);   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;   GPIO_Init(GPIOD, &GPIO_InitStructure);   /* Connect USART pins to AF */   GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);  // USART2_TX   GPIO_PinAFConfig(GPIOA, GPIO_PinSource3,  GPIO_AF_USART2);  // USART2_RX   GPIO_PinAFConfig(GPIOA, GPIO_PinSource8,  GPIO_AF_USART3);  // USART3_TX   GPIO_PinAFConfig(GPIOA, GPIO_PinSource9,  GPIO_AF_USART3);  // USART3_RX } //**************************************************************************** void USART2_Configuration(void) {   USART_InitTypeDef USART_InitStructure;   /* USARTx configuration ------------------------------------------------------*/   /* USARTx configured as follow:         - BaudRate = 9600 baud         - Word Length = 8 Bits         - One Stop Bit         - No parity         - Hardware flow control disabled (RTS and CTS signals)         - Receive and transmit enabled   */   USART_InitStructure.USART_BaudRate = 4800;   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(USART2, &USART_InitStructure);   USART_Cmd(USART2, ENABLE); } //**************************************************************************** void USART3_Configuration(void) {   USART_InitTypeDef USART_InitStructure;   /* USARTx configuration ------------------------------------------------------*/   /* USARTx configured as follow:         - BaudRate = 9600 baud         - Word Length = 8 Bits         - One Stop Bit         - No parity         - Hardware flow control disabled (RTS and CTS signals)         - Receive and transmit enabled   */   USART_InitStructure.USART_BaudRate = 4800;   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(USART3, &USART_InitStructure);   USART_Cmd(USART3, ENABLE); } //**************************************************************************** /************************ Function USART2 send String ******************/ void USART_Puts(char *s) {   while(*s)//check end of string   {     while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait until transmission ready     USART_SendData(USART2, *s++); // Send Char   } } /*********************Function USART2 send Character *********************/ void USART_Putc(char c) {      while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait until transmission ready      USART_SendData(USART2,c); // Send Char } /**************************************************************************************/ int main(void) {   SystemInit();   RCC_Configuration();   GPIO_Configuration();   USART2_Configuration();   USART3_Configuration();   char tmp[50];   int i=0;   while(1)   {     if (USART_GetFlagStatus(USART3, USART_FLAG_RXNE) != RESET) // Check for Full       tmp[i++] = USART_ReceiveData(USART3);              USART_Puts(tmp);       i++;       if (i >= 50)         i = 0;   }   while(1); // Don't want to exit } //**************************************************************************** #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

[Tesla DeLorean]

Posted on March 25, 2015 at 20:28

Got some inconsistencies in the GPIO bank, pins and AF settings there. Stuff needs to be coherent.

Quick blind mod

#include ''main.h''
//****************************************************************************
void RCC_Configuration(void)
{
/* USART2 and 3 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2 | RCC_APB1Periph_USART3, ENABLE);
/* GPIOA and B clock enable */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB, ENABLE);
}
//****************************************************************************
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIO Configuration */
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Connect USART pins to AF */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2); // USART2_TX
GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2); // USART2_RX
GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3); // USART3_TX PB.10
GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3); // USART3_RX PB.11 (in from GPS TX)
}
//****************************************************************************
void USART2_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 4800 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 4800;
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(USART2, &USART_InitStructure);
USART_Cmd(USART2, ENABLE);
}
//****************************************************************************
void USART3_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 4800 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 4800;
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(USART3, &USART_InitStructure);
USART_Cmd(USART3, ENABLE);
}
//****************************************************************************
/************************ Function USART2 send String ******************/
void USART_Puts(char *s)
{
while(*s)//check end of string
{
while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait until transmission ready
USART_SendData(USART2, *s++); // Send Char
}
}
/*********************Function USART2 send Character *********************/
void USART_Putc(char c)
{
while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait until transmission ready
USART_SendData(USART2,c); // Send Char
}
/**************************************************************************************/
int main(void)
{
SystemInit();
RCC_Configuration();
GPIO_Configuration();
USART2_Configuration();
USART3_Configuration();
while(1) // Don't want to exit
{
uint16_t Data;
// Pipe from USART3 to USART2
while(USART_GetFlagStatus(USART3, USART_FLAG_RXNE) == RESET); // Wait for Char
Data = USART_ReceiveData(USART3); // Collect Char
while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait for Empty
USART_SendData(USART2, Data); // Echo Char
}
}
//****************************************************************************
#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

[Mikk Leini]

Posted on March 25, 2015 at 21:15 The original post was too long to process during our migration. Please click on the provided URL to read the original post. https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I6gs&d=%2Fa%2F0X0000000btJ%2FH3QedEMV_5bq6wm_ybTos_RW64x4TSMzGfw2QlahfkI&asPdf=false

[kitjazax]

Posted on March 25, 2015 at 22:06

thanks for your kind.It 's really a big help for have your  code as reference

[kitjazax]

Posted on March 25, 2015 at 22:08

thank you very much for taking your time

to help

[kitjazax]

Posted on April 01, 2015 at 19:02 The original post was too long to process during our migration. Please click on the provided URL to read the original post. https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I6gO&d=%2Fa%2F0X0000000bt8%2F44QfoR0Fvo6NFasDKog8eum1_ZzXWtI8v8uUkN3uYTc&asPdf=false

[Tesla DeLorean]

Posted on April 01, 2015 at 20:37

You'll need some looping to wait for many characters, rather than just one if it happens to be in the receive buffer.

[Tesla DeLorean]

Posted on April 01, 2015 at 22:16

#include ''main.h''
//****************************************************************************
void RCC_Configuration(void)
{
/* USART2 and 3 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2 | RCC_APB1Periph_USART3, ENABLE);
/* GPIOA clock enable */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB, ENABLE);
}
//****************************************************************************
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIO Configuration */
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Connect USART pins to AF */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2); // USART2_TX
GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2); // USART2_RX
GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3); // USART3_TX
GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3); // USART3_RX
}
//****************************************************************************
void USART2_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 9600 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 4800;
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(USART2, &USART_InitStructure);
USART_Cmd(USART2, ENABLE);
}
//*************************************************************************************
void USART3_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 9600 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 4800;
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(USART3, &USART_InitStructure);
USART_Cmd(USART3, ENABLE);
USART_ITConfig(USART3, USART_IT_RXNE | USART_IT_TXE, ENABLE);
}
//**************************************************************************************
// Console USART Routines
//**************************************************************************************
void USART_Putc(char c)
{
while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait until transmission ready
USART_SendData(USART2,c); // Send Char
}
//**************************************************************************************
void USART_Puts(char *s)
{
while(*s)//check end of string
USART_Putc(*s++); // Send Char
}
//**************************************************************************************
char USART_Getc(void)
{
while(USART_GetITStatus(USART2, USART_IT_RXNE) == RESET); // Wait until received character
return((char)(USART_ReceiveData(USART2) & 0xFF));
}
//**************************************************************************************
// GPS Routines
//**************************************************************************************
char GPS_Getc(void)
{
while(USART_GetITStatus(USART3, USART_IT_RXNE) == RESET); // Wait until received character
return((char)(USART_ReceiveData(USART3) & 0xFF));
}
//**************************************************************************************
#define BUFFERS 15
#define BUFFER_LEN 80
char rxbuff[BUFFERS][BUFFER_LEN];
char temp[BUFFER_LEN];
//check for first $ and store more chars into rxbuffer until 

 then start new index and do the same ...
void checkNMEAdata2Buffer(void)
{
char ch;
uint8_t nr=0,pos=0;
while(nr < BUFFERS)
{
ch = GPS_Getc();
if (ch=='$') // Resync line
pos = 0;
rxbuff[nr][pos]=ch;
pos++;
if ((ch == '
') || (ch == '
') || (pos == (BUFFER_LEN - 1))
{
rxbuff[nr][pos]=0; // NUL terminate
pos=0;
nr++;
}
} // while
}
//****************************************************************************
//get NMEA sentece form index
void getNMEAdata(uint8_t nr)
{
uint8_t n;
char ch;
for(n=0;n<BUFFER_LEN;n++)
{
ch=rxbuff[nr][n];
temp[n]=ch;
if(ch==0) break;
}
}
//****************************************************************************
int main(void)
{
RCC_Configuration();
GPIO_Configuration();
USART3_Configuration();
USART2_Configuration();
checkNMEAdata2Buffer();
getNMEAdata(0);
USART_Puts(temp);
while(1)
{
}
}
//****************************************************************************
#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
//****************************************************************************