AD7705Comm.h

#ifndef __AD7705COMM_H
#define __AD7705COMM_H
 
/*
 * AD7705 class to read data at a given sampling rate
 *
 * Copyright (c) 2007  MontaVista Software, Inc.
 * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
 * Copyright (c) 2013-2022  Bernd Porr <mail@berndporr.me.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 *
 */
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#include <thread>  
#include <string>
 
#ifndef NDEBUG
#define DEBUG
#endif
 
 
class AD7705callback {
public:
    virtual void hasSample(float sample) = 0;
};
 
 
struct AD7705settings {
    std::string spiDevice = "/dev/spidev0.0";
    
    enum SamplingRates {
        FS50HZ  = 0,
        FS60HZ  = 1,
        FS250HZ = 2,
        FS500HZ = 3
    };
 
    SamplingRates samplingRate = FS50HZ;
 
    enum PGAGains {
        G1   = 0,
        G2   = 1,
        G4   = 2,
        G8   = 3,
        G16  = 4,
        G32  = 5,
        G64  = 6,
        G128 = 7
    };
 
    PGAGains pgaGain = G1;
 
    enum AIN {
        AIN1 = 0,
        AIN2 = 1
    };
 
    AIN channel = AIN1;
 
    enum Modes {
        Bipolar  = 0,
        Unipolar = 1
    };
 
    Modes mode = Unipolar;
};
 
 
class AD7705Comm {
 
public:
    AD7705Comm(AD7705settings settings);
 
    ~AD7705Comm();
       
    void registerCallback(AD7705callback* cb);
 
    void unRegisterCallback();
 
    void start();
 
    void stop();
 
private:
    const uint8_t mode = SPI_CPHA | SPI_CPOL;
    const int drdy_GPIO = 22;
    const uint32_t speed = 500000;
    const uint16_t delay = 0;
    const uint8_t bpw   = 8;
    static constexpr float ADC_REF = 2.5;
    int fd = 0;
    std::thread* daqThread = nullptr;
    int running = 0;
    AD7705callback* ad7705callback = nullptr;
    AD7705settings ad7705settings;
 
    int spi_transfer(int fd, uint8_t* tx, uint8_t* rx, int n);
    void writeReset(int fd);
    void writeReg(int fd, uint8_t v);
    uint8_t readReg(int fd);
    int16_t readData(int fd);
    static void run(AD7705Comm* ad7705comm);
 
        inline float pgaGain() {
        return (float)(1 << ad7705settings.pgaGain);
    }
 
    inline uint8_t commReg() {
        return ((uint8_t)(ad7705settings.channel));
    }
 
    static int getSysfsIRQfd(int gpio);
    static int fdPoll(int gpio_fd, int timeout);
    static void gpio_unexport(int gpio);
};
 
 
#endif