main.c

/*
 * -------------------------------------------------------------------------------
 *
 * Copyright (c) 2022, Daniel Gorbea
 * All rights reserved.
 *
 * This source code is licensed under the MIT-style license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * -------------------------------------------------------------------------------
 *
 *  A pio program to capture signal edges on any pins of the RP2040:
 *
 *  Base pin is 0. CAPTURE_EDGE_PIN_COUNT is 2 -> Pins 0 & 1 can be captured
 *
 *  Set the number of pins to capture in capture_edge.pio with CAPTURE_EDGE_PIN_COUNT
 *
 *  Connect a signal to pins 0 and/or 1 and check output at 115200
 *
 * -------------------------------------------------------------------------------
 */

#include <stdio.h>

#include "capture_edge.h"
#include "hardware/clocks.h"
#include "pico/stdlib.h"

float clk_div = 1;
volatile uint capture_counter, pin;
volatile float frequency, duty, duration_cycle;
volatile bool is_captured;
volatile edge_type_t edge_type;

static void capture_pin_0_handler(uint counter, edge_type_t edge) {
    static uint counter_edge_rising = 0, counter_edge_falling = 0;
    capture_counter = counter;
    pin = 0;
    is_captured = true;
    edge_type = edge;

    if (edge == EDGE_RISING) {
        duration_cycle = (float)(counter - counter_edge_rising) / clock_get_hz(clk_sys) * COUNTER_CYCLES;
        frequency = 1 / duration_cycle;
        counter_edge_rising = counter;
    }
    if (edge == EDGE_FALLING) {
        float duration_pulse = (float)(counter - counter_edge_rising) / clock_get_hz(clk_sys) * COUNTER_CYCLES;
        duty = duration_pulse / duration_cycle * 100;
        counter_edge_falling = counter;
    }
}

static void capture_pin_1_handler(uint counter, edge_type_t edge) {
    static uint counter_edge_rising = 0, counter_edge_falling = 0;
    capture_counter = counter;
    pin = 1;
    is_captured = true;
    edge_type = edge;

    if (edge == EDGE_RISING) {
        duration_cycle = (float)(counter - counter_edge_rising) / clock_get_hz(clk_sys) * COUNTER_CYCLES;
        frequency = 1 / duration_cycle;
        counter_edge_rising = counter;
    }
    if (edge == EDGE_FALLING) {
        float duration_pulse = (float)(counter - counter_edge_rising) / clock_get_hz(clk_sys) * COUNTER_CYCLES;
        duty = duration_pulse / duration_cycle * 100;
        counter_edge_falling = counter;
    }
}

int main() {
    PIO pio = pio0;         // values: pio0, pio1
    uint pin_base = 0;      // starting gpio to capture
    uint irq = PIO0_IRQ_0;  // values for pio0: PIO0_IRQ_0, PIO0_IRQ_1. values for pio1: PIO1_IRQ_0, PIO1_IRQ_1

    stdio_init_all();

    capture_edge_init(pio, pin_base, clk_div, irq);
    capture_edge_set_handler(0, capture_pin_0_handler);
    capture_edge_set_handler(1, capture_pin_1_handler);

    while (true) {
        if (is_captured) {
            printf("\n\rCapture pin %u. Counter: %u State: %s Duration(us): %.0f", pin, capture_counter,
                   edge_type == EDGE_FALLING ? "High" : "Low ", duration_cycle * 1000000);
            if (edge_type == EDGE_RISING) printf(" Freq(Hz): %.1f Duty: %.1f", frequency, duty);
            is_captured = false;
        }
    }
}