/**
* @brief Initialize USART2
*/
void UART2_Init(void) {
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
// Enable clocks
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
// USART2 TX on PA2
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
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);
// USART2 RX on PA3
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
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);
// Connect USART2 TX pin to AF2
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);
// USART initialization
USART_InitStructure.USART_BaudRate = UART2_BAUDRATE;
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);
// Enable USART2
USART_Cmd(USART2, ENABLE);
// Enable RXNE interrupt
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
// Disable TXE interrupt
USART_ITConfig(USART2, USART_IT_TXE, DISABLE);
// Enable USART2 global interrupt
NVIC_EnableIRQ(USART2_IRQn);
// Initialize RX FIFO
rxFifo.buf = rxBuffer;
rxFifo.len = UART2_BUF_LEN;
FIFO_Add(&rxFifo);
// Initialize TX FIFO
txFifo.buf = txBuffer;
txFifo.len = UART2_BUF_LEN;
FIFO_Add(&txFifo);
}
/**
* @brief Initialize communication terminal interface.
* @param baud Required baud rate
*/
void COMM_Init(int baud) {
// pass baud rate
// callback for received data and callback for transmitted data
COMM_HAL_Init(baud, COMM_RxCallback, COMM_TxCallback);
// Initialize RX FIFO for receiving data from PC
rxFifo.buf = rxBuffer;
rxFifo.len = COMM_BUF_LEN_RX;
FIFO_Add(&rxFifo);
// Initialize TX FIFO for transferring data to PC
txFifo.buf = txBuffer;
txFifo.len = COMM_BUF_LEN_TX;
FIFO_Add(&txFifo);
}
/**
* @brief Initialize communication terminal interface.
*
* @param baud Required baud rate
*/
void COMM_Init(uint32_t baud) {
// pass baud rate
// callback for received data and callback for
// transmitted data
COMM_HAL_Init(baud, COMM_RxCallback, COMM_TxCallback);
// Initialize RX FIFO
rxFifo.buf = rxBuffer;
rxFifo.len = COMM_BUF_LEN;
FIFO_Add(&rxFifo);
// Initialize TX FIFO
txFifo.buf = txBuffer;
txFifo.len = COMM_BUF_LEN;
FIFO_Add(&txFifo);
}
/****************************************************************************
* DESCRIPTION: Transmits a frame using the UART
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Send_Frame(
volatile struct mstp_port_struct_t *mstp_port, /* port specific data */
uint8_t * buffer, /* frame to send (up to 501 bytes of data) */
uint16_t nbytes)
{ /* number of bytes of data (up to 501) */
uint16_t i = 0; /* loop counter */
uint8_t turnaround_time;
if (!buffer)
return;
while (!FIFO_Empty(&FIFO_Tx)) {
/* buffer is not empty. Wait for ISR to transmit. */
};
/* wait 40 bit times since reception */
if (RS485_Baud_Rate == 9600)
turnaround_time = 4;
else if (RS485_Baud_Rate == 19200)
turnaround_time = 2;
else
turnaround_time = 1;
while (mstp_port->SilenceTimer < turnaround_time) {
/* The line has not been silent long enough, so wait. */
};
if (FIFO_Add(&FIFO_Tx, buffer, nbytes)) {
/* disable the receiver */
PIE3bits.RC2IE = 0;
RCSTA2bits.CREN = 0;
/* enable the transceiver */
RS485_TX_ENABLE = 1;
RS485_RX_DISABLE = 1;
/* enable the transmitter */
TXSTA2bits.TXEN = 1;
PIE3bits.TX2IE = 1;
/* reset the silence timer per MSTP spec, sort of */
mstp_port->SilenceTimer = 0;
}
return;
}
