Posted on January 13, 2014 at 19:48 Hi,
I have the stn32f4 discovery kit, and I tried to run the following code to send chracters to the uart :
-------------------------------------------------------
#include ''stm32f4xx.h''
/**************************************************************************************/
void RCC_Configuration(void)
{
/* Enable GPIO clock */
RCC_AHB1PeriphClockCmd (RCC_AHB1Periph_GPIOA, ENABLE);
/* Enable USART clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
}
/**************************************************************************************/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Connect PA9 or PA1 to USART1_Tx */
//GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_USART1);
/* Connect PA10 or PA2 to USART1_Rx */
//GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART1);
/* Configure USART Tx as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; // GPIO_Pin_1 or GPIO_Pin_9
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Configure USART Rx as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; // GPIO_Pin_2 or GPIO_Pin_10
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
/**************************************************************************************/
void USART1_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USART resources configuration (Clock, GPIO pins and USART registers) ----*/
USART_InitStructure.USART_BaudRate = 1200;
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 configuration */
USART_Init(USART1, &USART_InitStructure);
/* Enable USART */
USART_Cmd(USART1, ENABLE);
}
/**************************************************************************************/
int main(void)
{
RCC_Configuration();
GPIO_Configuration();
USART1_Configuration();
while(1)
{
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET); // Wait for Empty
USART_SendData(USART1, 0x49); // Send 'I'
}
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
-------------------------------------------------------
This code runs well if I assign uart TX to pin PA9 and RX to PA10, but if I try to assign pins PA1 and PA2 for TX and RX, I cannot see the output signal (both signals stuck to Vcc).
Can you help me?
Thank you in advance
regards,
Michele
