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#include <stdint.h>
#include <string.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#ifndef PIN
#error need to define a PIN
#endif
#define B_RED (1 << 0)
#define B_YLW (1 << 1)
static void usart_rx()
{
UCSR0B = (1 << RXCIE0) /* recv int en */
| (1 << RXEN0); /* do RX */
}
static void usart_rxpoll()
{
UCSR0B = (1 << RXEN0); /* do RX*/
}
static void usart_dis()
{
UCSR0B = 0;
}
#define CLK (1 << 3)
#define DATA (1 << 1)
static uint8_t send_byte(uint8_t byte)
{
uint8_t cntr, bit, parity = 1, rv;
usart_dis();
rv = UDR0;
/* make clock low, request clock from keyboard */
PORTD = 0;
DDRD = CLK;
#define delay(x) for (cntr = 0; cntr < x; cntr++) __asm__ volatile ("nop\n")
delay(200);
DDRD = CLK | DATA;
delay(10);
DDRD = DATA;
PORTD = CLK;
#define wait_CLKlo while (PIND & CLK) __asm__ volatile ("nop\n")
#define wait_CLKhi while (!(PIND & CLK)) __asm__ volatile ("nop\n")
#define wait_CLK wait_CLKhi; wait_CLKlo; delay(3)
for (bit = 0; bit < 8; bit++) {
wait_CLK;
if (byte & 1) {
PORTD = CLK | DATA;
parity++;
} else {
PORTD = CLK;
}
byte >>= 1;
}
wait_CLK;
PORTD = (parity & 1) ? (CLK | DATA) : CLK;
wait_CLK;
PORTD = CLK | DATA;
wait_CLKhi;
DDRD = 0;
wait_CLKlo;
wait_CLKhi;
usart_rxpoll();
while (!(UCSR0A & (1 << RXC0)))
__asm__ volatile("nop\n");
rv = UDR0;
usart_rx();
return rv;
}
uint8_t ext, brk, pressed, state;
const char passwd[4] = PIN;
char code[sizeof(passwd)];
const char kbc_60[32] = {
'_', '_', '_', '_', '_', '_', '_', '_', /* 60 - 67 */
'_', '1', '_', '4', '7', '_', '_', '_', /* 68 - 6f */
'0', '.', '2', '5', '6', '8', '_', '_', /* 70 - 77 */
'_', '+', '3', '-', '*', '9', '_', '_' /* 78 - 7f */
};
#define KBLED_STATE 0x02
#define KBLED_ERROR 0x04
#define KBLED_OK 0x01
#define DDRD_BEEP 0x20
#define DDRD_OPEN 0x40
#define DDRD_CLOSE 0x80
#define CNTRTOP 96
#define CNTRERR 90
#define CNTRKEYBEEPOFF 4
#define CNTROK 88 /* regulates length of keymatic button press */
#define CNTROK_BEEPOFF 90
#define CNTROK_BEEPON2 94
#define OK_WAIT 3 /* mult CNTRTOP */
static uint8_t cntr = 0;
ISR(SIG_OVERFLOW0)
{
switch (cntr) {
case CNTRTOP:
DDRD = 0;
if (state > 1) {
state--;
} else if (state == 1) {
memset(&code, 0, sizeof(code));
state = 0;
} else {
send_byte(0xed);
send_byte(KBLED_STATE);
}
cntr = 0;
return;
case CNTROK_BEEPOFF:
if (state > 1)
DDRD &= ~DDRD_BEEP;
break;
case CNTROK_BEEPON2:
if (state > 1)
DDRD |= DDRD_BEEP;
break;
case CNTRKEYBEEPOFF:
DDRD = 0;
break;
case 0x00:
if (state <= 1) {
send_byte(0xed);
send_byte(state ? KBLED_STATE : 0);
}
break;
}
cntr++;
}
ISR(SIG_USART_RECV)
{
uint8_t data = UDR0, now;
if (data == 0xe0) {
ext = 0x80;
return;
}
if (data == 0xf0) {
brk = 1;
return;
}
if (data < 0x80) {
if (brk) {
pressed = 0;
brk = 0;
ext = 0;
return;
} else {
now = (data | ext);
ext = 0;
if (pressed == now)
return;
pressed = now;
if (pressed > 0x60 && pressed < 0x80 && pressed != 0x76 && pressed != 0x77) {
uint8_t c;
for (c = 1; c < sizeof(code); c++)
code[c - 1] = code[c];
code[sizeof(code) - 1] = kbc_60[pressed - 0x60];
TCNT0 = 0;
state = 1;
send_byte(0xed);
send_byte(0x00);
DDRD = DDRD_BEEP;
cntr = 0;
TIFR0 = (1 << TOV0);
};
if (pressed == 0xda || pressed == 0x76 || pressed == 0x77) {
if (memcmp(passwd, code, sizeof(passwd))) {
TCNT0 = 0;
memset(&code, 0, sizeof(code));
state = 0;
send_byte(0xed);
send_byte(KBLED_ERROR);
DDRD = DDRD_BEEP;
cntr = CNTRERR;
TIFR0 = (1 << TOV0);
return;
}
TCNT0 = 0;
send_byte(0xed);
send_byte(KBLED_OK);
state = OK_WAIT;
cntr = CNTROK;
TIFR0 = (1 << TOV0);
DDRD = DDRD_BEEP | ((pressed == 0xda) ? DDRD_OPEN : DDRD_CLOSE);
}
}
return;
}
}
int main()
{
DDRB = (1 << 4) | B_RED | B_YLW;
PORTB = (1 << 4) | B_RED | B_YLW;
DDRD = 0;
PORTD = 0x3f;
TCCR0A = 0;
TIMSK0 = (1 << TOIE0);
TCCR0B = (1 << CS02);
UCSR0C = (1 << UMSEL00) /* synch mode */
| (1 << UPM01) | (1 << UPM00) /* odd parity */
| (1 << UCSZ01) | (1 << UCSZ00) /* 8-bit chars */
| (0 << UCPOL0); /* polarity: sample on falling */
usart_rx();
sei();
while (1)
;
}
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