mhsw-espurna/code/espurna/sensors/EmonADC121Sensor.h

// -----------------------------------------------------------------------------
// ADS121-based Energy Monitor Sensor over I2C
// Copyright (C) 2017 by Xose Pérez <xose dot perez at gmail dot com>
// -----------------------------------------------------------------------------

#pragma once

#include "Arduino.h"
#include "BaseSensor.h"
#include "EmonSensor.h"
#include "EmonAnalogSensor.h"

#if I2C_USE_BRZO
#include <brzo_i2c.h>
#else
#include <Wire.h>
#endif

// ADC121 Registers
#define ADC121_REG_RESULT       0x00
#define ADC121_REG_ALERT        0x01
#define ADC121_REG_CONFIG       0x02
#define ADC121_REG_LIMITL       0x03
#define ADC121_REG_LIMITH       0x04
#define ADC121_REG_HYST         0x05
#define ADC121_REG_CONVL        0x06
#define ADC121_REG_CONVH        0x07

#define ADC121_RESOLUTION       12

class EmonADC121Sensor : public EmonAnalogSensor {

    public:

        // ---------------------------------------------------------------------
        // Public
        // ---------------------------------------------------------------------

        void setAddress(unsigned char address) {
            _address = address;
        }

        // ---------------------------------------------------------------------
        // Sensor API
        // ---------------------------------------------------------------------

        // Initialization method, must be idempotent
        void begin() {

            // Discover
            if (_address == 0) {
                unsigned char addresses[] = {0x50, 0x51, 0x52, 0x54, 0x55, 0x56, 0x58, 0x59, 0x5A};
                _address = i2cFindFirst(9, addresses);
            }
            if (_address == 0) {
                _error = SENSOR_ERROR_UNKNOWN_ID;
                return;
            }

            // Init sensor
            #if I2C_USE_BRZO
                uint8_t buffer[2];
                buffer[0] = ADC121_REG_CONFIG;
                buffer[1] = 0x00;
                brzo_i2c_start_transaction(_address, I2C_SCL_FREQUENCY);
                brzo_i2c_write(buffer, 2, false);
                brzo_i2c_end_transaction();
            #else
                Wire.beginTransmission(_address);
                Wire.write(ADC121_REG_CONFIG);
                Wire.write(0x00);
                Wire.endTransmission();
            #endif

            // Just one channel
            _count = _magnitudes;

            // Bit depth
            _resolution = ADC121_RESOLUTION;

            // Call the parent class method
            EmonSensor::begin();

            // warmup channel 0 (the only one)
            _pivot = _adc_counts >> 1;
            read(0, _pivot);

        }

        // Descriptive name of the sensor
        String name() {
            char buffer[30];
            snprintf(buffer, sizeof(buffer), "EMON @ ADC121 @ I2C (0x%02X)", _address);
            return String(buffer);
        }

        // Pre-read hook (usually to populate registers with up-to-date data)
        void pre() {

            if (_address == 0) {
                _error = SENSOR_ERROR_UNKNOWN_ID;
                return;
            }

            EmonAnalogSensor:pre();

        }

    protected:

        // ---------------------------------------------------------------------
        // Protected
        // ---------------------------------------------------------------------

        unsigned int readADC(unsigned char channel) {

            unsigned int value;

            #if I2C_USE_BRZO
                uint8_t buffer[2];
                buffer[0] = ADC121_REG_RESULT;
                brzo_i2c_start_transaction(_address, I2C_SCL_FREQUENCY);
                brzo_i2c_write(buffer, 1, false);
                brzo_i2c_read(buffer, 2, false);
                brzo_i2c_end_transaction();
                value = (buffer[0] & 0x0F) << 8;
                value |= buffer[1];
            #else
                Wire.beginTransmission(_address);
                Wire.write(ADC121_REG_RESULT);
                Wire.endTransmission();
                Wire.requestFrom(_address, (unsigned char) 2);
                value = (Wire.read() & 0x0F) << 8;
                value = value + Wire.read();
            #endif

            return value;

        }

        unsigned char _address = 0;

};