nuclear@0: #ifdef XTAL
nuclear@0: #define F_CLK	XTAL
nuclear@0: #define F_CPU	XTAL
nuclear@0: #else
nuclear@0: #warning "compiled for 1mhz internal rc osc. serial comms won't work"
nuclear@0: #define F_CLK	1000000
nuclear@0: #define F_CPU	1000000
nuclear@0: #endif
nuclear@0: 
nuclear@0: #include <stdio.h>
nuclear@0: #include <avr/io.h>
nuclear@0: #include <avr/interrupt.h>
nuclear@0: #include <util/delay.h>
nuclear@0: #include <avr/power.h>
nuclear@0: 
nuclear@0: static int uart_send_char(char c, FILE *fp);
nuclear@0: static int uart_get_char(FILE *fp);
nuclear@0: 
nuclear@0: #define BUF_SZ	64
nuclear@0: #define BUF_IDX_MASK	0x3f
nuclear@0: #define NEXT_IDX(x)	(((x) + 1) & BUF_IDX_MASK)
nuclear@0: static char outbuf[BUF_SZ];
nuclear@0: static volatile unsigned char out_rd, out_wr;
nuclear@0: static char inbuf[BUF_SZ];
nuclear@0: static volatile unsigned char in_rd, in_wr;
nuclear@0: 
nuclear@0: static FILE std_stream = FDEV_SETUP_STREAM(uart_send_char, uart_get_char, _FDEV_SETUP_RW);
nuclear@0: 
nuclear@0: 
nuclear@0: 
nuclear@0: void init_serial(long baud)
nuclear@0: {
nuclear@0: 	unsigned int ubrr_val = F_CLK / 16 / baud - 1;
nuclear@0: 
nuclear@0: 	power_usart0_enable();
nuclear@0: 
nuclear@0: 	/* set baud generator timer reset value */
nuclear@0: 	UBRR0H = (unsigned char)(ubrr_val >> 8);
nuclear@0: 	UBRR0L = (unsigned char)ubrr_val;
nuclear@0: 
nuclear@0: 	/* enable rx/tx and recv interrupt */
nuclear@0: 	UCSR0B = (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0);
nuclear@0: 	/* set frame format: 8n1 */
nuclear@0: 	UCSR0C = 3 << UCSZ00;
nuclear@0: 
nuclear@0: 	stdin = stdout = stderr = &std_stream;
nuclear@0: }
nuclear@0: 
nuclear@0: int have_input(void)
nuclear@0: {
nuclear@0: 	return in_wr != in_rd;
nuclear@0: }
nuclear@0: 
nuclear@0: static int uart_send_char(char c, FILE *fp)
nuclear@0: {
nuclear@0: 	int next;
nuclear@0: 
nuclear@0: 	if(c == '\n') {
nuclear@0: 		uart_send_char('\r', fp);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	next = NEXT_IDX(out_wr);
nuclear@0: 	while(next == out_rd);
nuclear@0: 
nuclear@0: 	outbuf[out_wr] = c;
nuclear@0: 	out_wr = next;
nuclear@0: 
nuclear@0: 	/* enable the Tx data register empty interrupt */
nuclear@0: 	UCSR0B |= 1 << UDRIE0;
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: static int uart_get_char(FILE *fp)
nuclear@0: {
nuclear@0: 	char c;
nuclear@0: 
nuclear@0: 	while(in_rd == in_wr);
nuclear@0: 
nuclear@0: 	c = inbuf[in_rd];
nuclear@0: 	in_rd = NEXT_IDX(in_rd);
nuclear@0: 	return c;
nuclear@0: }
nuclear@0: 
nuclear@0: ISR(USART0_RX_vect)
nuclear@0: {
nuclear@0: 	char c = UDR0;
nuclear@0: 
nuclear@0: 	if(c == '\r') {
nuclear@0: 		c = '\n';
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	inbuf[in_wr] = c;
nuclear@0: 	in_wr = NEXT_IDX(in_wr);
nuclear@0: }
nuclear@0: 
nuclear@0: /* USART Tx data register empty (can send more data) */
nuclear@0: ISR(USART0_UDRE_vect)
nuclear@0: {
nuclear@0: 	if(out_rd != out_wr) {
nuclear@0: 		UDR0 = outbuf[out_rd];
nuclear@0: 		out_rd = NEXT_IDX(out_rd);
nuclear@0: 	} else {
nuclear@0: 		/* no more data to send for now, disable the interrupt */
nuclear@0: 		UCSR0B &= ~(1 << UDRIE0);
nuclear@0: 	}
nuclear@0: }