Posted on December 07, 2012 at 06:46Hi,
I am trying to communicate to STM32F107VC microcontroller via UART5. I am debugging the DR register of UART5 port, but it seems it is always zero (I am using IAR EWARM with ST-LINK V2 via STM32F1Discovery).
the PCLK1 is configured to be 31.25 MHz
Here is my code:
main.c:
--------
/* Setup STM32 system (clock, PLL and Flash configuration) */
RCC_init();
IO_init();
USART_init();
//EXT_CRT_SECTION();
// send test data to USART1
/* Infinite loop */
while (1)
{
// send test data via USART1
USART_SendData(UART5, (uint16_t)'T');
while(USART_GetFlagStatus(UART5,USART_FLAG_TXE) == RESET); // wait until the TDR (Tx register) data is transfered to the shift register
LED_Test();
}
}
--------------------------------------------------------------------------------------------
init.c:
-----
void USART_init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART1_InitStructure;
USART_InitTypeDef UART5_InitStructure;
// Release reset and enable clock
USART_DeInit(UART5);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART5, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD,ENABLE);
RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOD,DISABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC,ENABLE);
RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOC,DISABLE);
/* UART5 Configuration
*=====================*/
// configure the IO ports for UART5 Tx as output
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(GPIOC, &GPIO_InitStructure);
// configure the IO ports for UART5 Rx as input
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOD, &GPIO_InitStructure);
// configure the UART5 serial registers
UART5_InitStructure.USART_BaudRate = 115200;
UART5_InitStructure.USART_WordLength = USART_WordLength_8b;
UART5_InitStructure.USART_StopBits = USART_StopBits_1;
UART5_InitStructure.USART_Parity = USART_Parity_No;
UART5_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
UART5_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
USART_Init(UART5,&UART5_InitStructure);
// enable UART5
USART_Cmd(UART5, ENABLE);
} stm32f10x_usart.c
------------------
void USART_SendData(USART_TypeDef* USARTx, uint16_t Data)
{
/* Check the parameters */
assert_param(IS_USART_ALL_PERIPH(USARTx));
assert_param(IS_USART_DATA(Data));
/* Transmit Data */
USARTx->DR = (Data & (uint16_t)0x01FF);
}
