nuclear@2: #include <stdio.h>
nuclear@2: #include <avr/io.h>
nuclear@2: #include <avr/interrupt.h>
nuclear@2: #include <util/delay.h>
nuclear@2: #include "amigakb.h"
nuclear@2: #include "defs.h"
nuclear@2: #include "timer.h"
nuclear@2: 
nuclear@2: #define TIMEOUT_MSEC	143
nuclear@2: 
nuclear@2: static void resync(void);
nuclear@2: 
nuclear@2: void amikb_sendkey(unsigned char keycode, int press)
nuclear@2: {
nuclear@2: 	int i;
nuclear@2: 	static unsigned char prev_keycode = 0xff;
nuclear@2: 
nuclear@2: 	/* keycode bit transfer order: 6 5 4 3 2 1 0 7 (7 is pressed flag) */
nuclear@2: 	keycode = (keycode << 1) | (~press & 1);
nuclear@2: 	if(keycode == prev_keycode) return;
nuclear@2: 	prev_keycode = keycode;
nuclear@2: 
nuclear@2: 	/* make sure we don't pulse the lines while grabbing control
nuclear@2: 	 * by first reinstating the pullups before changing direction
nuclear@2: 	 */
nuclear@2: 	PORTD |= ACLK_BIT | ADATA_BIT;
nuclear@2: 	DDRD |= ACLK_BIT | ADATA_BIT;
nuclear@2: 
nuclear@2: 	/* pulse the data line and wait for about 100us */
nuclear@2: 	PORTD &= ~ADATA_BIT;
nuclear@2: 	_delay_us(20);
nuclear@2: 	PORTD |= ADATA_BIT;
nuclear@2: 	_delay_us(100);
nuclear@2: 
nuclear@2: 	for(i=0; i<8; i++) {
nuclear@2: 		/* data line is inverted */
nuclear@2: 		if(keycode & 0x80) {
nuclear@2: 			PORTD &= ~ADATA_BIT;
nuclear@2: 		} else {
nuclear@2: 			PORTD |= ADATA_BIT;
nuclear@2: 		}
nuclear@2: 		keycode <<= 1;
nuclear@2: 		_delay_us(20);
nuclear@2: 		/* pulse the clock */
nuclear@2: 		cli();
nuclear@2: 		PORTD &= ~ACLK_BIT;
nuclear@2: 		EIFR |= (1 << INTF1);
nuclear@2: 		sei();
nuclear@2: 		_delay_us(20);
nuclear@2: 		PORTD |= ACLK_BIT;
nuclear@2: 		_delay_us(20);
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	/* similarly tristate first, then drop the pullups */
nuclear@2: 	DDRD &= ~(ACLK_BIT | ADATA_BIT);
nuclear@2: 	PORTD &= ~(ACLK_BIT | ADATA_BIT);
nuclear@2: 
nuclear@2: 	/* wait for ack */
nuclear@2: 	reset_timer();
nuclear@2: 	while(PIND & ADATA_BIT) {
nuclear@2: 		if(get_msec() >= TIMEOUT_MSEC) {
nuclear@2: 			resync();
nuclear@2: 			break;
nuclear@2: 		}
nuclear@2: 	}
nuclear@2: }
nuclear@2: 
nuclear@2: void amikb_reset(void)
nuclear@2: {
nuclear@2: 	cli();
nuclear@2: 	PORTD &= ~ARST_BIT;
nuclear@2: 	DDRD |= ARST_BIT;
nuclear@2: 	_delay_ms(10);
nuclear@2: 	PORTD |= ARST_BIT;
nuclear@2: 	DDRD &= ~ARST_BIT;
nuclear@2: 	sei();
nuclear@2: }
nuclear@2: 
nuclear@2: static void resync(void)
nuclear@2: {
nuclear@2: 	PORTD |= ACLK_BIT | ADATA_BIT;
nuclear@2: 	printf("lost sync\r\n");
nuclear@2: 
nuclear@2: 	for(;;) {
nuclear@2: 		cli();
nuclear@2: 		DDRD |= ACLK_BIT | ADATA_BIT;
nuclear@2: 
nuclear@2: 		PORTD &= ~ACLK_BIT;
nuclear@2: 		EIFR |= (1 << INTF1);	/* clear interrupt raised by the previous line */
nuclear@2: 		sei();
nuclear@2: 		_delay_us(20);
nuclear@2: 		PORTD |= ACLK_BIT;
nuclear@2: 
nuclear@2: 		DDRD &= ~(ACLK_BIT | ADATA_BIT);
nuclear@2: 
nuclear@2: 		reset_timer();
nuclear@2: 		while(get_msec() < TIMEOUT_MSEC) {
nuclear@2: 			if(!(PIND & ADATA_BIT)) {
nuclear@2: 				return;
nuclear@2: 			}
nuclear@2: 		}
nuclear@2: 	}
nuclear@2: }
nuclear@2: 
nuclear@2: static void handle_cmd(unsigned char cmd)
nuclear@2: {
nuclear@2: 	printf("amikbd got cmd: %x\r\n", (unsigned int)cmd);
nuclear@2: }
nuclear@2: 
nuclear@2: ISR(INT1_vect)
nuclear@2: {
nuclear@2: 	static unsigned char value;
nuclear@2: 	static int nbits;
nuclear@2: 
nuclear@2: 	value <<= 1;
nuclear@2: 	if(PIND & ADATA_BIT) {
nuclear@2: 		value |= 1;
nuclear@2: 	}
nuclear@2: 	if(++nbits >= 8) {
nuclear@2: 		handle_cmd(value);
nuclear@2: 		nbits = 0;
nuclear@2: 		value = 0;
nuclear@2: 	}
nuclear@2: }