Encoder.cpp

// Pico Electronic Leadscrew
// https://github.com/funkenjaeger/pico-els
//
// MIT License
//
// Copyright (c) 2025 Evan Dudzik
//
// This software is based on the Clough42 Electronic Leadscrew project under the MIT license
// https://github.com/clough42/electronic-leadscrew
// Leveraged portions of this software are Copyright (c) 2019 James Clough
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include <cmath>
#include "Encoder.h"
#include "Configuration.h"

Encoder :: Encoder( void )
{
    previous = 0;
    rpm = 0;
}

void Encoder :: initHardware(void)
{
    this->pio = pio1;
    this->pio_sm = 0; 
    pio_sm_claim(this->pio, this->pio_sm);   
    pio_add_program_at_offset(pio, &quadrature_encoder_program, 0); // This PIO code must be loaded at address 0 because it uses computed jumps
    quadrature_encoder_program_init(this->pio, this->pio_sm, QUADRATURE_B_PIN, 0);

    add_repeating_timer_ms(-1000/_ENCODER_RPM_CALC_HZ, encoder_timer_callback, this, &timer);
}

int32_t Encoder :: getPosition(void)
{
    #ifdef REVERSE_ENCODER
        return -quadrature_encoder_get_count(this->pio, this->pio_sm);
    #else
        return quadrature_encoder_get_count(this->pio, this->pio_sm);
    #endif
}

bool encoder_timer_callback(repeating_timer *rt)
{
    Encoder * encoder = static_cast<Encoder *>(rt->user_data);
    int32_t position = encoder->getPosition();

    encoder->rpm = (uint16_t)(abs(position - encoder->previous) * _ENCODER_RPM_CALC_HZ * 60 / ENCODER_RESOLUTION);

    encoder->previous = position;
    return true;
}