198 lines
2.7 KiB
C
198 lines
2.7 KiB
C
#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <util/delay.h>
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#include <stdbool.h>
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#include <stdint.h>
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static volatile int8_t kbd_state = 0;
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static volatile uint8_t kbd_input = 0;
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static volatile uint8_t kbd_output = 0;
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static volatile uint8_t kbd_flags = 0;
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static volatile uint8_t ts = 10;
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#define KBD_FLAG_ERROR (_BV(0))
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#define KBD_FLAG_BREAK (_BV(1))
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#define KBD_FLAG_EXT (_BV(2))
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#define KBD_CODE_UP 0xe075
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#define KBD_CODE_LEFT 0xe06b
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#define KBD_CODE_DOWN 0xe072
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#define KBD_CODE_RIGHT 0xe074
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static inline bool kbd_data() {
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return (PINC & (1 << 0));
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}
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static inline bool kbd_clock() {
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return (PINC & (1 << 1));
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}
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ISR(PCINT1_vect) {
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if (kbd_clock())
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return;
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if (kbd_state < 0) {
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if (kbd_state >= -8) {
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if (kbd_output & (1 << (-1-kbd_state)))
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PORTC |= 0x01;
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else
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PORTC &= ~0x01;
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kbd_state--;
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return;
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}
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if (kbd_state == -9) {
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if ((__builtin_popcount(kbd_output) & 1) == 0)
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PORTC |= 0x01;
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else
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PORTC &= ~0x01;
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kbd_state--;
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return;
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}
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if (kbd_state == -10) {
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kbd_state--;
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DDRC &= ~0x01;
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PORTC |= 0x01;
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return;
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}
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kbd_state = 0;
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return;
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}
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bool data = kbd_data();
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if (kbd_state == 0) {
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if (!data) { /* start bit */
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kbd_input = 0;
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kbd_state++;
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}
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return;
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}
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if (kbd_state <= 8) {
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kbd_input |= (data << (kbd_state-1));
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kbd_state++;
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return;
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}
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if (kbd_state == 9) {
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if ((__builtin_popcount(kbd_input) & 1) == data)
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kbd_flags |= KBD_FLAG_ERROR;
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kbd_state++;
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return;
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}
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kbd_state = 0;
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if (kbd_flags & KBD_FLAG_ERROR) {
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/* Retry */
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return;
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}
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if (kbd_input == 0xe0) {
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kbd_flags |= KBD_FLAG_EXT;
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return;
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}
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if (kbd_input == 0xf0) {
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kbd_flags |= KBD_FLAG_BREAK;
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return;
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}
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uint16_t code = kbd_input;
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if (kbd_flags & KBD_FLAG_EXT)
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code |= 0xe000;
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if (!(kbd_flags & KBD_FLAG_BREAK)) {
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switch (code) {
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case KBD_CODE_UP:
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if (ts > 0)
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ts--;
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break;
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case KBD_CODE_DOWN:
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if (ts < 31)
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ts++;
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break;
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}
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}
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kbd_flags = 0;
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}
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void kbd_send(uint8_t command) {
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while (kbd_state) {} /* wait for idle */
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DDRC |= 0x02;
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PORTC &= ~0x02;
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_delay_us(100);
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DDRC |= 0x01;
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PORTC &= ~0x01;
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_delay_us(10);
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DDRC &= ~0x02;
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PORTC |= 0x02;
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kbd_output = command;
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kbd_state = -1;
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/* wait for idle */
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while (kbd_state) {}
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while (!kbd_state) {}
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while (kbd_state) {}
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}
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int main(void) {
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DDRB = 0xff;
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PORTB = 0;
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DDRC = 0x00;
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PORTC = 0x03;
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PCMSK1 = (1 << PCINT9);
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PCICR = (1 << PCIE1);
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sei();
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kbd_send(0xff);
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uint8_t l = 0;
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while(true) {
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uint8_t state = PORTB ^ 0x20;
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PORTB = state;
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if (state & 0x20) {
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l = (l+1)%3;
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kbd_send(0xed);
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kbd_send(1 << l);
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}
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uint32_t i;
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for (i = 0; i < (1 << ts); i++)
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_delay_ms(1);
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}
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return 0;
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}
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