Tx-Rx problem with USART in STM32L- Discovery !

[bipinkumar117]

Posted on April 25, 2012 at 17:11

This is my code for Transmission :

void USART3_tx(void){ USART_InitTypeDef USART_InitStructure; GPIO_InitTypeDef GPIO_InitStructure;   /* Enable GPIOB and USART3 clock */  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);   GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3);  GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3);   /* Configure USART Tx and Rx as alternate function push-pull */  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;  GPIO_Init(GPIOB, &GPIO_InitStructure);   /* USARTx configured as follow:  - BaudRate = 9600 baud    - Word Length = 8 Bits  - One Stop Bit  - No parity  - Hardware flow control not enabled (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_Tx | USART_Mode_Rx; USART_Init(USART3, &USART_InitStructure);  USART_Cmd(USART3, ENABLE); }int main(void){ GPIO_InitTypeDef GPIO_InitStructure; RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;    GPIO_Init(GPIOB, &GPIO_InitStructure); USART3_tx(); USART_SendData(USART3, 0xFF); while(USART_GetFlagStatus(USART3, USART_FLAG_TXE) == RESET); GPIO_WriteBit(GPIOB, GPIO_Pin_6, Bit_SET);}This is the code for Reception :void USART3_rx(void){ USART_InitTypeDef USART_InitStructure; GPIO_InitTypeDef GPIO_InitStructure;   RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);    GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3);  GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3);     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;  GPIO_Init(GPIOB, &GPIO_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_HardwareFlowControl = USART_HardwareFlowControl_None; USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; USART_Init(USART3, &USART_InitStructure);  USART_Cmd(USART3, ENABLE);}int main(void){ GPIO_InitTypeDef GPIO_InitStructure; RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;    GPIO_Init(GPIOB, &GPIO_InitStructure); GPIO_WriteBit(GPIOB, GPIO_Pin_7, Bit_SET); USART3_rx(); while(USART_GetFlagStatus(USART3, USART_FLAG_RXNE) != RESET); while(USART_ReceiveData(USART3)!= 0xFF); GPIO_WriteBit(GPIOB, GPIO_Pin_6, Bit_SET); GPIO_WriteBit(GPIOB, GPIO_Pin_7, Bit_RESET);}I am using two Xbee modules with two STM32L-Discovery boards to realize this Tx - Rx.Kindly Help! #stm32l---discovery #usart #uart

[Tesla DeLorean]

Posted on April 25, 2012 at 20:22

The RX code looks busted.

main()
{
// ... Init code
GPIO_WriteBit(GPIOB, GPIO_Pin_7, Bit_SET);
USART3_rx();
do
{
while(USART_GetFlagStatus(USART3, USART_FLAG_RXNE) == RESET);
}
while(USART_ReceiveData(USART3) != 0xFF);
GPIO_WriteBit(GPIOB, GPIO_Pin_6, Bit_SET);
GPIO_WriteBit(GPIOB, GPIO_Pin_7, Bit_RESET);
while(1); // do not exit
}

[becker007]

Posted on April 30, 2013 at 08:59 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=0680X000006I6mz&d=%2Fa%2F0X0000000bvU%2FRAFMXzyckiHoC1zI8D1N19TOzFGd9exSUxw1uS5gtL8&asPdf=false

[Tesla DeLorean]

Posted on April 30, 2013 at 13:39

Mixing APB1/APB2 references.

Failing to wait on USART TXE before USART_SendData()

[becker007]

Posted on May 08, 2013 at 12:51 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=0680X000006I6n4&d=%2Fa%2F0X0000000bvV%2FQ0c3jbOupoJOyRr1uZ1CsIj5nqKdSNLy7FCp5_NxSVI&asPdf=false

[Tesla DeLorean]

Posted on May 08, 2013 at 13:29

I would imagine generic C code for the protocol exists.

Couple of recommendations for code, use bytes for the data array, and front test TXE rather than back test TC.

void SendArray(uint8_t *zeichen)
{
for(i=0;i<5;i++)
{
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
USART_SendData(USART1, zeichen[i]);
}
}