v3_firmware/lib/SPS30/SPS30.cpp

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4.4 KiB
C++

/*
.cpp - SPS30 Sensor Library
Copyright (c) 2020-2021, Stefan Brand
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Arduino.h>
#include "SPS30.h"
SPS30::SPS30() {
}
uint8_t SPS30::getSensorData(char *payload, uint8_t startbyte) {
uint8_t data[30];
for (uint8_t i = 0; i < 30; i++)
data[i] = 0xFF;
uint16_t massPM1, massPM25, massPM4, massPM10, typPM;
// Start Measuring, Integer Output
write(SPS30_START_MEASUREMENT, 0x0500);
// Wait for Stable Values (max 30s according to datasheet)
delay(30000);
if (hasData()) {
write(SPS30_READ_MEASUREMENT);
Wire.requestFrom(SPS30_I2C_ADDRESS, 30);
if (Wire.available() != 0) {
Wire.readBytes(data, 30);
for (uint8_t i = 0; i < 30; i++)
data[i] = 0xFE;
// PM1.0
if (data[3] == calcCRC(data, 2))
massPM1 = data[0] << 8 | data[1];
// PM2.5
if (data[5] == calcCRC(data+3, 2))
massPM25 = data[3] << 8 | data[4];
// PM4
if (data[8] == calcCRC(data+6, 2))
massPM4 = data[6] << 8 | data[7];
// PM10
if (data[11] == calcCRC(data+9, 2))
massPM10 = data[9] << 8 | data[10];
// Typical Size
if (data[29] == calcCRC(data+27, 2))
typPM = data[27] << 8 | data[28];
}
}
write(SPS30_STOP_MEASUREMENT);
uint16ToPayload(massPM1, payload, startbyte);
uint16ToPayload(massPM25, payload, startbyte+2);
uint16ToPayload(massPM4, payload, startbyte+4);
uint16ToPayload(massPM10, payload, startbyte+6);
uint16ToPayload(typPM, payload, startbyte+8);
}
// Check if Sensor has Data
bool SPS30::hasData(void) {
uint16_t resp = readReg(SPS30_GET_DATA_READY);
return (resp == 1);
}
// Read a 16Bit Register
uint16_t SPS30::readReg(uint16_t regAddr) {
Wire.beginTransmission(SPS30_I2C_ADDRESS);
Wire.write(regAddr >> 8);
Wire.write(regAddr & 0xFF);
Wire.endTransmission();
Wire.requestFrom(SPS30_I2C_ADDRESS, 2);
if (Wire.available() != 0) {
uint8_t msb = Wire.read();
uint8_t lsb = Wire.read();
return ((uint16_t)msb << 8 | lsb);
}
return(0);
}
bool SPS30::write(uint16_t cmd) {
Wire.beginTransmission(SPS30_I2C_ADDRESS);
Wire.write(cmd >> 8);
Wire.write(cmd & 0xFF);
if (Wire.endTransmission() != 0)
return(false);
return(true);
}
bool SPS30::write(uint16_t cmd, uint16_t arg){
uint8_t crcdata[2];
crcdata[0] = arg >> 8;
crcdata[1] = arg & 0xFF;
uint8_t csum = calcCRC(crcdata, 2);
Wire.beginTransmission(SPS30_I2C_ADDRESS);
Wire.write(cmd >> 8);
Wire.write(cmd & 0xFF);
Wire.write(arg >> 8);
Wire.write(arg & 0xFF);
Wire.write(csum);
if (Wire.endTransmission() != 0)
return(false);
return(true);
}
// Calculate the Checksum
uint8_t SPS30::calcCRC(uint8_t data[], uint8_t len) {
uint8_t csum = 0xFF;
for (uint8_t x = 0; x < len; x++)
{
csum ^= data[x];
for (uint8_t i = 0; i < 8; i++)
{
if ((csum & 0x80) != 0)
csum = (uint8_t)((csum << 1) ^ 0x31);
else
csum <<= 1;
}
}
return csum;
}