mirror of https://github.com/arendst/Tasmota.git
244 lines
7.1 KiB
C++
244 lines
7.1 KiB
C++
/*!
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* @file Adafruit_SGP30.cpp
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*
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* @mainpage Adafruit SGP30 gas sensor driver
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*
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* @section intro_sec Introduction
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*
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* This is the documentation for Adafruit's SGP30 driver for the
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* Arduino platform. It is designed specifically to work with the
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* Adafruit SGP30 breakout: http://www.adafruit.com/products/3709
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*
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* These sensors use I2C to communicate, 2 pins (SCL+SDA) are required
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* to interface with the breakout.
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit and open-source hardware by purchasing
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* products from Adafruit!
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*
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*
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* @section author Author
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* Written by Ladyada for Adafruit Industries.
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*
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* @section license License
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* BSD license, all text here must be included in any redistribution.
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*
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*/
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#if ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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#include "Adafruit_SGP30.h"
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//#define I2C_DEBUG
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/**************************************************************************/
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/*!
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@brief Instantiates a new SGP30 class
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*/
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/**************************************************************************/
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Adafruit_SGP30::Adafruit_SGP30() {
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}
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/**************************************************************************/
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/*!
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@brief Setups the hardware and detects a valid SGP30. Initializes I2C
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then reads the serialnumber and checks that we are talking to an SGP30
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@param theWire Optional pointer to I2C interface, otherwise use Wire
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@returns True if SGP30 found on I2C, False if something went wrong!
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::begin(TwoWire *theWire) {
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_i2caddr = SGP30_I2CADDR_DEFAULT;
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if (theWire == NULL) {
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_i2c = &Wire;
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} else {
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_i2c = theWire;
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}
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_i2c->begin();
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uint8_t command[2];
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command[0] = 0x36;
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command[1] = 0x82;
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if (! readWordFromCommand(command, 2, 10, serialnumber, 3))
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return false;
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uint16_t featureset;
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command[0] = 0x20;
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command[1] = 0x2F;
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if (! readWordFromCommand(command, 2, 10, &featureset, 1))
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return false;
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//Serial.print("Featureset 0x"); Serial.println(featureset, HEX);
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if (featureset != SGP30_FEATURESET)
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return false;
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if (! IAQinit())
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return false;
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return true;
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}
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/**************************************************************************/
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/*!
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@brief Commands the sensor to begin the IAQ algorithm. Must be called after startup.
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@returns True if command completed successfully, false if something went wrong!
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::IAQinit(void) {
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uint8_t command[2];
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command[0] = 0x20;
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command[1] = 0x03;
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return readWordFromCommand(command, 2, 10);
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}
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/**************************************************************************/
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/*!
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@brief Commands the sensor to take a single eCO2/VOC measurement. Places results in {@link TVOC} and {@link eCO2}
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@returns True if command completed successfully, false if something went wrong!
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::IAQmeasure(void) {
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uint8_t command[2];
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command[0] = 0x20;
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command[1] = 0x08;
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uint16_t reply[2];
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if (! readWordFromCommand(command, 2, 12, reply, 2))
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return false;
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TVOC = reply[1];
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eCO2 = reply[0];
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return true;
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}
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/**************************************************************************/
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/*!
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@brief Request baseline calibration values for both CO2 and TVOC IAQ calculations. Places results in parameter memory locaitons.
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@param eco2_base A pointer to a uint16_t which we will save the calibration value to
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@param tvoc_base A pointer to a uint16_t which we will save the calibration value to
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@returns True if command completed successfully, false if something went wrong!
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::getIAQBaseline(uint16_t *eco2_base, uint16_t *tvoc_base) {
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uint8_t command[2];
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command[0] = 0x20;
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command[1] = 0x15;
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uint16_t reply[2];
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if (! readWordFromCommand(command, 2, 10, reply, 2))
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return false;
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*eco2_base = reply[0];
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*tvoc_base = reply[1];
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return true;
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}
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/**************************************************************************/
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/*!
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@brief Assign baseline calibration values for both CO2 and TVOC IAQ calculations.
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@param eco2_base A uint16_t which we will save the calibration value from
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@param tvoc_base A uint16_t which we will save the calibration value from
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@returns True if command completed successfully, false if something went wrong!
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::setIAQBaseline(uint16_t eco2_base, uint16_t tvoc_base) {
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uint8_t command[8];
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command[0] = 0x20;
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command[1] = 0x1e;
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command[2] = tvoc_base >> 8;
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command[3] = tvoc_base & 0xFF;
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command[4] = generateCRC(command+2, 2);
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command[5] = eco2_base >> 8;
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command[6] = eco2_base & 0xFF;
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command[7] = generateCRC(command+5, 2);
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return readWordFromCommand(command, 8, 10);
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}
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/**************************************************************************/
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/*!
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@brief I2C low level interfacing
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*/
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/**************************************************************************/
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boolean Adafruit_SGP30::readWordFromCommand(uint8_t command[], uint8_t commandLength, uint16_t delayms, uint16_t *readdata, uint8_t readlen)
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{
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uint8_t data;
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_i2c->beginTransmission(_i2caddr);
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#ifdef I2C_DEBUG
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Serial.print("\t\t-> ");
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#endif
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for (uint8_t i=0; i<commandLength; i++) {
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_i2c->write(command[i]);
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#ifdef I2C_DEBUG
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Serial.print("0x"); Serial.print(command[i], HEX); Serial.print(", ");
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#endif
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}
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#ifdef I2C_DEBUG
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Serial.println();
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#endif
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_i2c->endTransmission();
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delay(delayms);
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if (readlen == 0)
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return true;
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uint8_t replylen = readlen * (SGP30_WORD_LEN +1);
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if (_i2c->requestFrom(_i2caddr, replylen) != replylen)
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return false;
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uint8_t replybuffer[replylen];
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#ifdef I2C_DEBUG
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Serial.print("\t\t<- ");
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#endif
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for (uint8_t i=0; i<replylen; i++) {
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replybuffer[i] = _i2c->read();
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#ifdef I2C_DEBUG
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Serial.print("0x"); Serial.print(replybuffer[i], HEX); Serial.print(", ");
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#endif
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}
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#ifdef I2C_DEBUG
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Serial.println();
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#endif
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for (uint8_t i=0; i<readlen; i++) {
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uint8_t crc = generateCRC(replybuffer+i*3, 2);
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#ifdef I2C_DEBUG
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Serial.print("\t\tCRC calced: 0x"); Serial.print(crc, HEX);
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Serial.print(" vs. 0x"); Serial.println(replybuffer[i * 3 + 2], HEX);
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#endif
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if (crc != replybuffer[i * 3 + 2])
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return false;
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// success! store it
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readdata[i] = replybuffer[i*3];
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readdata[i] <<= 8;
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readdata[i] |= replybuffer[i*3 + 1];
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#ifdef I2C_DEBUG
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Serial.print("\t\tRead: 0x"); Serial.println(readdata[i], HEX);
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#endif
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}
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return true;
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}
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uint8_t Adafruit_SGP30::generateCRC(uint8_t *data, uint8_t datalen) {
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// calculates 8-Bit checksum with given polynomial
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uint8_t crc = SGP30_CRC8_INIT;
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for (uint8_t i=0; i<datalen; i++) {
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crc ^= data[i];
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for (uint8_t b=0; b<8; b++) {
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if (crc & 0x80)
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crc = (crc << 1) ^ SGP30_CRC8_POLYNOMIAL;
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else
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crc <<= 1;
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}
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}
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return crc;
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}
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