95 lines
2.4 KiB
C
95 lines
2.4 KiB
C
#include <dio.h>
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#include <stdio.h>
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#include <display.h>
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uint32_t read_capacitance(dio_t *dio) {
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uint32_t i;
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dio_set_direction(dio, LINE_OUT);
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dio_set(dio, 1);
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i = 0;
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dio_set_direction(dio, LINE_IN);
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while (dio_read(dio) > 0) i++;
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return i;
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}
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uint32_t calibrate(dio_t *dio) {
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uint32_t max = 0;
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for (uint8_t i = 0; i < 100; i++) {
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uint8_t cap = read_capacitance(dio);
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max = cap > max ? cap : max;
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_delay_ms(10);
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}
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return max;
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}
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int main(void) {
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dio_t sensor = (dio_t){ .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 0 };
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display_t display = {
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.reg = {
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.output = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 4 },
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.shift_clock = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 3 },
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.latch_clock = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 2 },
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},
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};
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display_init(&display);
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display_enable(&display);
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display_clear(&display);
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// calibration
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//
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// 100 times:
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// Output 1
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// Switch to Input
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// measure in a loop until the input is 0
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// save the measurement
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//
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// normal function
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// Output 1
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// Switch to input
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// measure in a loop until the input is 0
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// check against the saved measurement
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// enable pin if significantly higher than the saved measurement
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// update the average
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MCUCR |= _BV(PUD);
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uint8_t calibration_countdown = 0;
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uint32_t calibration = 0;
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bool touch = false;
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while (1) {
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if (calibration_countdown == 0 && !touch) {
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calibration = calibrate(&sensor);
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calibration_countdown = 100;
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char msg[20];
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snprintf(msg, 20, "calib: %6ld", calibration);
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display_set_location(&display, 0, 0);
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display_write_message(&display, msg);
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}
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uint32_t cap = read_capacitance(&sensor);
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if (cap > calibration) {
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display_set_location(&display, 1, 0);
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display_write_message(&display, "touch!");
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touch = true;
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} else if (touch) {
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display_set_location(&display, 1, 0);
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display_write_message(&display, " ");
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touch = false;
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}
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if (calibration_countdown > 0) {
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calibration_countdown--;
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}
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_delay_ms(100);
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}
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}
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