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#include <hardware.h>
#include <tty.h>
#include <stdint.h>
#include <input.h>
enum encoder_state {
START,
CW_START,
CW_NEXT,
CW_FINAL,
CCW_START,
CCW_NEXT,
CCW_FINAL,
CW = 0x10,
CCW = 0x20
};
/* State machine to keep track of encoder */
static const uint8_t encoder_table[7][4] = {
/* 00 01 10 11*/
[START] = { START, CCW_START, CW_START, START },
[CCW_START] = { CCW_NEXT, CCW_START, START, START },
[CCW_NEXT] = { CCW_NEXT, CCW_START, CCW_FINAL, START },
[CCW_FINAL] = { CCW_NEXT, START, CCW_FINAL, START | CCW },
[CW_START] = { CW_NEXT, START, CW_START, START },
[CW_NEXT] = { CW_NEXT, CW_FINAL, CW_START, START },
[CW_FINAL] = { CW_NEXT, CW_FINAL, START, START | CW }
};
struct fifo input_fifo = {0, 0, {0}};
void
input_event(void) __critical __interrupt(4)
{
if ((port_b_data & 0x03) != 0x03) {
// Encoder
uint8_t state = START;
uint8_t encoder;
uint8_t next_state;
do {
encoder = port_b_data & 0x03;
next_state = encoder_table[state][encoder];
state = next_state & 0x0F;
} while (state != START);
if (next_state == CW || next_state == CCW)
fifo_push(&input_fifo, next_state);
} else if (port_b_data & 0x7C) {
// Key pressed
for (int i = 0; i < 5; i++) {
uint8_t bit = 1 << (i + 2);
uint8_t state = !(port_b_data & bit);
if (state)
fifo_push(&input_fifo, i);
}
}
}
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