Subversion Repositories svnkaklik

/*------------------------------------------------*/
/* UART functions                                 */


#include <avr/io.h>
#include <avr/interrupt.h>
#include "uart.h"

#define SYSCLK          9216000
#define BAUD            115200


typedef struct _fifo {
        uint8_t idx_w;
        uint8_t idx_r;
        uint8_t count;
        uint8_t buff[64];
} FIFO;


static volatile
FIFO txfifo, rxfifo;



/* Initialize UART */

void uart_init()
{
        rxfifo.idx_r = 0;
        rxfifo.idx_w = 0;
        rxfifo.count = 0;
        txfifo.idx_r = 0;
        txfifo.idx_w = 0;
        txfifo.count = 0;

        UBRR0L = SYSCLK/BAUD/16-1;
        UCSR0B = _BV(RXEN0)|_BV(RXCIE0)|_BV(TXEN0);
}


/* Get a received character */

uint8_t uart_test ()
{
        return rxfifo.count;
}


uint8_t uart_get ()
{
        uint8_t d, i;


        i = rxfifo.idx_r;
        while(rxfifo.count == 0);
        d = rxfifo.buff[i++];
        cli();
        rxfifo.count--;
        sei();
        if(i >= sizeof(rxfifo.buff))
                i = 0;
        rxfifo.idx_r = i;

        return d;
}


/* Put a character to transmit */

void uart_put (uint8_t d)
{
        uint8_t i;


        i = txfifo.idx_w;
        while(txfifo.count >= sizeof(txfifo.buff));
        txfifo.buff[i++] = d;
        cli();
        txfifo.count++;
        UCSR0B = _BV(RXEN0)|_BV(RXCIE0)|_BV(TXEN0)|_BV(UDRIE0);
        sei();
        if(i >= sizeof(txfifo.buff))
                i = 0;
        txfifo.idx_w = i;
}


/* UART RXC interrupt */

SIGNAL(SIG_UART0_RECV)
{
        uint8_t d, n, i;


        d = UDR0;
        n = rxfifo.count;
        if(n < sizeof(rxfifo.buff)) {
                rxfifo.count = ++n;
                i = rxfifo.idx_w;
                rxfifo.buff[i++] = d;
                if(i >= sizeof(rxfifo.buff))
                        i = 0;
                rxfifo.idx_w = i;
        }
}


/* UART UDRE interrupt */

SIGNAL(SIG_UART0_DATA)
{
        uint8_t n, i;


        n = txfifo.count;
        if(n) {
                txfifo.count = --n;
                i = txfifo.idx_r;
                UDR0 = txfifo.buff[i++];
                if(i >= sizeof(txfifo.buff))
                        i = 0;
                txfifo.idx_r = i;
        }
        if(n == 0)
                UCSR0B = _BV(RXEN0)|_BV(RXCIE0)|_BV(TXEN0);
}