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Tasmota/lib/lib_i2c/Adafruit_SGP30-1.2.0/Adafruit_SGP30.cpp

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/*!
* @file Adafruit_SGP30.cpp
*
* @mainpage Adafruit SGP30 gas sensor driver
*
* @section intro_sec Introduction
*
* This is the documentation for Adafruit's SGP30 driver for the
* Arduino platform. It is designed specifically to work with the
* Adafruit SGP30 breakout: http://www.adafruit.com/products/3709
*
* These sensors use I2C to communicate, 2 pins (SCL+SDA) are required
* to interface with the breakout.
*
* Adafruit invests time and resources providing this open source code,
* please support Adafruit and open-source hardware by purchasing
* products from Adafruit!
*
*
* @section author Author
* Written by Ladyada for Adafruit Industries.
*
* @section license License
* BSD license, all text here must be included in any redistribution.
*
*/
#include "Arduino.h"
#include "Adafruit_SGP30.h"
//#define I2C_DEBUG
/*!
* @brief Instantiates a new SGP30 class
*/
Adafruit_SGP30::Adafruit_SGP30() {}
/*!
* @brief Setups the hardware and detects a valid SGP30. Initializes I2C
* then reads the serialnumber and checks that we are talking to an
* SGP30
* @param theWire
* Optional pointer to I2C interface, otherwise use Wire
* @param initSensor
* Optional pointer to prevent IAQinit to be called. Used for Deep
* Sleep.
* @return True if SGP30 found on I2C, False if something went wrong!
*/
boolean Adafruit_SGP30::begin(TwoWire *theWire, boolean initSensor) {
_i2caddr = SGP30_I2CADDR_DEFAULT;
_i2c = theWire;
_i2c->begin();
uint8_t command[2];
command[0] = 0x36;
command[1] = 0x82;
if (!readWordFromCommand(command, 2, 10, serialnumber, 3))
return false;
uint16_t featureset;
command[0] = 0x20;
command[1] = 0x2F;
if (!readWordFromCommand(command, 2, 10, &featureset, 1))
return false;
// Serial.print("Featureset 0x"); Serial.println(featureset, HEX);
if ((featureset & 0xF0) != SGP30_FEATURESET)
return false;
if (initSensor) {
if (!IAQinit())
return false;
}
return true;
}
/*!
* @brief Commands the sensor to perform a soft reset using the "General
* Call" mode. Take note that this is not sensor specific and all devices that
* support the General Call mode on the on the same I2C bus will perform this.
*
* @return True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::softReset(void) {
uint8_t command[2];
command[0] = 0x00;
command[1] = 0x06;
return readWordFromCommand(command, 2, 10);
}
/*!
* @brief Commands the sensor to begin the IAQ algorithm. Must be called
* after startup.
* @returns True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::IAQinit(void) {
uint8_t command[2];
command[0] = 0x20;
command[1] = 0x03;
return readWordFromCommand(command, 2, 10);
}
/*!
* @brief Commands the sensor to take a single eCO2/VOC measurement. Places
* results in {@link TVOC} and {@link eCO2}
* @return True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::IAQmeasure(void) {
uint8_t command[2];
command[0] = 0x20;
command[1] = 0x08;
uint16_t reply[2];
if (!readWordFromCommand(command, 2, 12, reply, 2))
return false;
TVOC = reply[1];
eCO2 = reply[0];
return true;
}
/*!
* @brief Commands the sensor to take a single H2/ethanol raw measurement.
* Places results in {@link rawH2} and {@link rawEthanol}
* @returns True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::IAQmeasureRaw(void) {
uint8_t command[2];
command[0] = 0x20;
command[1] = 0x50;
uint16_t reply[2];
if (!readWordFromCommand(command, 2, 25, reply, 2))
return false;
rawEthanol = reply[1];
rawH2 = reply[0];
return true;
}
/*!
* @brief Request baseline calibration values for both CO2 and TVOC IAQ
* calculations. Places results in parameter memory locaitons.
* @param eco2_base
* A pointer to a uint16_t which we will save the calibration
* value to
* @param tvoc_base
* A pointer to a uint16_t which we will save the calibration value to
* @return True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::getIAQBaseline(uint16_t *eco2_base,
uint16_t *tvoc_base) {
uint8_t command[2];
command[0] = 0x20;
command[1] = 0x15;
uint16_t reply[2];
if (!readWordFromCommand(command, 2, 10, reply, 2))
return false;
*eco2_base = reply[0];
*tvoc_base = reply[1];
return true;
}
/*!
* @brief Assign baseline calibration values for both CO2 and TVOC IAQ
* calculations.
* @param eco2_base
* A uint16_t which we will save the calibration value from
* @param tvoc_base
* A uint16_t which we will save the calibration value from
* @return True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::setIAQBaseline(uint16_t eco2_base, uint16_t tvoc_base) {
uint8_t command[8];
command[0] = 0x20;
command[1] = 0x1e;
command[2] = tvoc_base >> 8;
command[3] = tvoc_base & 0xFF;
command[4] = generateCRC(command + 2, 2);
command[5] = eco2_base >> 8;
command[6] = eco2_base & 0xFF;
command[7] = generateCRC(command + 5, 2);
return readWordFromCommand(command, 8, 10);
}
/*!
* @brief Set the absolute humidity value [mg/m^3] for compensation to
* increase precision of TVOC and eCO2.
* @param absolute_humidity
* A uint32_t [mg/m^3] which we will be used for compensation.
* If the absolute humidity is set to zero, humidity compensation
* will be disabled.
* @return True if command completed successfully, false if something went
* wrong!
*/
boolean Adafruit_SGP30::setHumidity(uint32_t absolute_humidity) {
if (absolute_humidity > 256000) {
return false;
}
uint16_t ah_scaled =
(uint16_t)(((uint64_t)absolute_humidity * 256 * 16777) >> 24);
uint8_t command[5];
command[0] = 0x20;
command[1] = 0x61;
command[2] = ah_scaled >> 8;
command[3] = ah_scaled & 0xFF;
command[4] = generateCRC(command + 2, 2);
return readWordFromCommand(command, 5, 10);
}
/*!
* @brief I2C low level interfacing
*/
boolean Adafruit_SGP30::readWordFromCommand(uint8_t command[],
uint8_t commandLength,
uint16_t delayms,
uint16_t *readdata,
uint8_t readlen) {
_i2c->beginTransmission(_i2caddr);
#ifdef I2C_DEBUG
Serial.print("\t\t-> ");
#endif
for (uint8_t i = 0; i < commandLength; i++) {
_i2c->write(command[i]);
#ifdef I2C_DEBUG
Serial.print("0x");
Serial.print(command[i], HEX);
Serial.print(", ");
#endif
}
#ifdef I2C_DEBUG
Serial.println();
#endif
_i2c->endTransmission();
delay(delayms);
if (readlen == 0)
return true;
uint8_t replylen = readlen * (SGP30_WORD_LEN + 1);
if (_i2c->requestFrom(_i2caddr, replylen) != replylen)
return false;
uint8_t replybuffer[replylen];
#ifdef I2C_DEBUG
Serial.print("\t\t<- ");
#endif
for (uint8_t i = 0; i < replylen; i++) {
replybuffer[i] = _i2c->read();
#ifdef I2C_DEBUG
Serial.print("0x");
Serial.print(replybuffer[i], HEX);
Serial.print(", ");
#endif
}
#ifdef I2C_DEBUG
Serial.println();
#endif
for (uint8_t i = 0; i < readlen; i++) {
uint8_t crc = generateCRC(replybuffer + i * 3, 2);
#ifdef I2C_DEBUG
Serial.print("\t\tCRC calced: 0x");
Serial.print(crc, HEX);
Serial.print(" vs. 0x");
Serial.println(replybuffer[i * 3 + 2], HEX);
#endif
if (crc != replybuffer[i * 3 + 2])
return false;
// success! store it
readdata[i] = replybuffer[i * 3];
readdata[i] <<= 8;
readdata[i] |= replybuffer[i * 3 + 1];
#ifdef I2C_DEBUG
Serial.print("\t\tRead: 0x");
Serial.println(readdata[i], HEX);
#endif
}
return true;
}
uint8_t Adafruit_SGP30::generateCRC(uint8_t *data, uint8_t datalen) {
// calculates 8-Bit checksum with given polynomial
uint8_t crc = SGP30_CRC8_INIT;
for (uint8_t i = 0; i < datalen; i++) {
crc ^= data[i];
for (uint8_t b = 0; b < 8; b++) {
if (crc & 0x80)
crc = (crc << 1) ^ SGP30_CRC8_POLYNOMIAL;
else
crc <<= 1;
}
}
return crc;
}
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