65 lines
1.9 KiB
C
65 lines
1.9 KiB
C
#define __AVR_ATmega2560__
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#define F_CPU 16000000UL
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#include <avr/io.h>
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#include <util/delay.h>
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#include <stdbool.h>
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#include "lib/util.h"
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#include "lib/7segment.h"
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#include "lib/7segment_4digits.h"
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/**
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* O O O O O O O O
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* DDRF x x x x x x x x
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* \-\-\-\-\-\-\-\--- 7 segment output
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*
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* I I O O O O O O
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* DDRK x x x x x x x x
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* | | \-\-\-\--- digit selection output
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* \-\--------------- Button input
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*/
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void main() {
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DDRF = 0b11111111;
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DDRK = 0b00001111;
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PORTK = 0b11000000; // set pull-up
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uint32_t millis = 0;
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bool counting = false;
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bool pressed_pause = false;
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bool pressed_clear = false;
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while(1) {
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// show_float() doesn't actually print to the display directly, it only updates
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// a variable stored in memory. We call `update_display_all_sync()` periodically,
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// which reads the stored variable and outputs it.
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show_float(millis / 1000.0f);
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// Cycles through all 4 displays, turns them on for a set amount of time
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// while displaying the value set by `show_float()` earlier and returns
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// the total amount waited.
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uint32_t sleep_time = update_display_all_sync();
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if (counting) {
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// We can use the returned sleep_time to (inaccurately) count time.
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millis += sleep_time;
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}
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// If the button connected to PIN7 is pressed, pause or unpause the counter.
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if (!pressed_pause && bit_is_clear(PINK, PINK7)) {
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counting = !counting;
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pressed_pause = true;
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} else if (pressed_pause && bit_is_set(PINK, PINK7)) {
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pressed_pause = false;
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}
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// If the button connected to PIN6 is pressed, reset and pause the counter.
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if (bit_is_clear(PINK, PINK6)) {
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millis = 0;
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counting = false;
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pressed_clear = true;
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} else pressed_clear = false;
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}
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}
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