nymea-plugins/i2cdevices/ads1115channel.cpp

92 lines
2.9 KiB
C++

// SPDX-License-Identifier: GPL-3.0-or-later
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* Copyright (C) 2013 - 2024, nymea GmbH
* Copyright (C) 2024 - 2025, chargebyte austria GmbH
*
* This file is part of nymea-plugins.
*
* nymea-plugins 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 3 of the License, or
* (at your option) any later version.
*
* nymea-plugins is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with nymea-plugins. If not, see <https://www.gnu.org/licenses/>.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include "ads1115channel.h"
#include "extern-plugininfo.h"
#include <unistd.h>
#define REGISTER_CONVERSATION 0x00
#define REGISTER_CONFIG 0x01
#define OPERATIONAL_STATE_IDLE 0x00
#define OPERATIONAL_STATE_CONVERSATION 0x80
#define CONVERSION_MODE_CONTINUOUS 0x00
#define CONVERSION_MODE_SINGLE 0x40
#define CHANNEL_MODE_DIFFERENTIAL 0x00
#define CHANNEL_MODE_SINGLE 0x01
ADS1115Channel::ADS1115Channel(const QString &portName, int address, int channel, Gain gain, QObject *parent):
I2CDevice(portName, address, parent),
m_channel(channel),
m_gain(gain)
{
}
QByteArray ADS1115Channel::readData(int fd)
{
// Start a configuration conversation
unsigned char writeBuf[3] = {0};
writeBuf[0] = REGISTER_CONFIG; // Select config register
writeBuf[1] |= OPERATIONAL_STATE_CONVERSATION; // Set conversation bit
writeBuf[1] |= CHANNEL_MODE_SINGLE;
writeBuf[1] |= m_channel << 4;
writeBuf[1] |= m_gain << 1;
writeBuf[1] |= CONVERSION_MODE_SINGLE;
writeBuf[2] = 0x85; // 0b10000101: Data rate: 100, not using comparator
if (write(fd, writeBuf, 3) != 3) {
qCWarning(dcI2cDevices()) << "ADS1115: could not write config register";
return QByteArray();
}
// Wait for device to accept configuration (conversation bit is cleared)
char readBuf[2] = {0};
do {
if (read(fd, readBuf, 2) != 2) {
qCWarning(dcI2cDevices()) << "ADS1115: could not read ADC data";
return QByteArray();
}
} while (!(readBuf[0] & OPERATIONAL_STATE_CONVERSATION));
// Select conversation register
writeBuf[0] = REGISTER_CONVERSATION;
if (write(fd, writeBuf, 1) != 1) {
qCWarning(dcI2cDevices()) << "ADS1115: could not write select register";
return QByteArray();
}
// Read conversation register
if (read(fd, readBuf, 2) != 2) {
qCWarning(dcI2cDevices()) << "ADS1115: could not read ADC data";
return QByteArray();
}
return QByteArray(readBuf, 2);
}