Posted on January 17, 2014 at 16:40Please help,
I am able to transmit on USART1 okay. They receive does not appear to be working.
I am using the provided discovery code, with the following USART Setup- (I modified this slightly from the half-duplex code as I am simply attempting to send a byte at a time, then receive a response.
void USART1_Configure(void)
{
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
// Configure USART1 pins: Rx and Tx
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);
// IS THIS CORRECT for full duplex? GPIO_Init(GPIOA, &GPIO_InitStructure); // Commit Changes
USART_InitStructure.USART_BaudRate = 9600; /
/?? Demo code requests BAUD in Integer format, correct ? 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;
In full duplex mode do you have to configure the USART for send, then change to receive mode? It appears that what I Tx is in the Rx register. With the DEMO software, the desired BAUD rate is set as an integer (this is the default), but comments have a formula. How can the actual baud rate be measured?
Sample code is like
USART_SendData(USART1, 0xAA);
Rx= USART_ReceiveData(USART1);
uint16_t USART_ReceiveData(USART_TypeDef* USARTx)
{
/* Check the parameters */
assert_param(IS_USART_ALL_PERIPH(USARTx));
/* Receive Data */
return (uint16_t)(USARTx->RDR & (uint16_t)0x01FF);
Note I have not yet implemented DMA for the USART this may simply be an issue of missing data... I wanted to Tx / Rx byte to check interface before implemented DMA or interrupt routines. I am also a bit confused, the routines provided use uint16_t while only a byte (unsigned char) is sent, that is okay if the uint16_t datasent is =< 0xFF but will be truncated if larger, right?
I thank you in advance for any assistance you can provide.
#stm32f0308 #discovery #usart
