3 files changed, 287 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0b31adb
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+*.flash
+*.eeprom
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..642202a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,38 @@
+MCU=atmega48
+AVRDUDE=avrdude
+ACC=avr-gcc
+AOBJCOPY=avr-objcopy
+ALD=avr-ld
+CFLAGS=-Wall -Wextra -Wno-unused-parameter -pedantic -std=c99
+ifdef PIN
+DPIN=-DPIN=\"$(PIN)\"
+endif
+ACFLAGS=-g -mmcu=$(MCU) $(CFLAGS) $(DPIN) -Os -mcall-prologues
+# ALDFLAGS=-L/usr/avr/lib/avr4 -L/usr/lib/binutils/avr/2.18
+LD=gcc
+CC=gcc
+CXX=g++ -g
+LDXX=g++ -g
+
+love: kbc.flash
+
+%.flash: %.ld.o
+        $(AOBJCOPY) -O binary $< $@
+
+%.eeprom: %.ld.o
+        $(AOBJCOPY) -j .eeprom -O binary $^ $@
+
+%.ld.o: %.o
+        $(ACC) $(ACFLAGS) $(ALDFLAGS) -o $@ $<
+
+%.o: %.c
+        $(ACC) $(ACFLAGS) -c -o $@ $<
+
+flash: kbc.flash
+        $(AVRDUDE) -y -p m48 -E noreset -U $^
+
+clean:
+        rm -f *.flash *.eeprom *.o
+
+.PHONY: love flash clean
+
diff --git a/kbc.c b/kbc.c
new file mode 100644
index 0000000..6a161c3
--- /dev/null
+++ b/kbc.c
@@ -0,0 +1,246 @@
+#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)
+                ;
+}
+