Subversion Repositories FlightCtrl

#include <avr/io.h>
#include <avr/interrupt.h>
#include "uart1.h"
#include "ubx.h"

#define USART1_BAUD 57600

/****************************************************************/
/*              Initialization of the USART1                    */
/****************************************************************/
void usart1_init(void) {
        // USART1 Control and Status Register A, B, C and baud rate register
        uint8_t sreg = SREG;
        uint16_t ubrr = (uint16_t) ((uint32_t) F_CPU / (8 * USART1_BAUD) - 1);

        // disable all interrupts before reconfiguration
        cli();

        // disable RX-Interrupt, disable TX-Interrupt, disable DRE-Interrupt
        UCSR1B &= ~ ((1 << RXCIE1) | (1 << TXCIE1) | (1 << UDRIE1));

        // set direction of RXD1 and TXD1 pins
        // set RXD1 (PD2) as an input pin,  set TXD1 (PD3) as an output pin
        PORTD |= (1 << PORTD2) | (1 << PORTD3);
        DDRD &= ~(1 << DDD2);
        DDRD |= (1 << DDD3);

        // USART0 Baud Rate Register
        // set clock divider
        UBRR1H = (uint8_t) (ubrr >> 8);
        UBRR1L = (uint8_t) ubrr;

        // enable double speed operation
        UCSR1A |= (1 << U2X1);
        // enable receiver and transmitter
        UCSR1B = (1 << TXEN1) | (1 << RXEN1);
        // set asynchronous mode,  no parity, 1 stop bit
        UCSR1C &= ~((1 << UMSEL11) | (1 << UMSEL10) | (1 << UPM11) | (1 << UPM10) | (1 << USBS1));

        // 8-bit
        UCSR1B &= ~(1 << UCSZ12);
        UCSR1C |= (1 << UCSZ11) | (1 << UCSZ10);

        // flush receive buffer explicit
        while (UCSR1A & (1 << RXC1))
                UDR1;

        // enable interrupts at the end
        // enable RX-Interrupt
        UCSR1B |= (1 << RXCIE1);
        // enable TX-Interrupt
        //UCSR1B |= (1 << TXCIE1);
        // enable DRE interrupt
        //UCSR1B |= (1 << UDRIE1);

        // restore global interrupt flags
        SREG = sreg;
}

/****************************************************************/
/*               USART1 data register empty ISR                 */
/****************************************************************/
/*ISR(USART1_UDRE_vect) {
 }
 */

/****************************************************************/
/*               USART1 transmitter ISR                         */
/****************************************************************/
/*ISR(USART1_TX_vect) {
 }
 */
/****************************************************************/
/*               USART1 receiver ISR                            */
/****************************************************************/
ISR(USART1_RX_vect) {
    ubx_parser(UDR1);  // get data byte and put it into the ubx protocol parser
}