Diff: scd30.cpp

Revision:

0:2a16832400d0

Child:

1:24bb922e179c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scd30.cpp	Mon Sep 10 17:51:13 2018 +0000
@@ -0,0 +1,275 @@
+#include "mbed.h"
+#include "scd30.h"
+
+//-----------------------------------------------------------------------------
+// Constructor 
+
+scd30::scd30(PinName sda, PinName scl, int i2cFrequency)  : _i2c(sda, scl) {
+        _i2c.frequency(i2cFrequency);
+}
+
+//-----------------------------------------------------------------------------
+// Destructor
+
+scd30::~scd30() {
+}
+
+//-----------------------------------------------------------------------------
+// start auto-measurement with barometer reading (in mB)
+//
+
+uint8_t scd30::startMeasurement(uint16_t baro)
+{
+    i2cBuff[0] = SCD30_CMMD_STRT_CONT_MEAS >> 8;
+    i2cBuff[1] = SCD30_CMMD_STRT_CONT_MEAS & 255;
+    i2cBuff[2] = baro >> 8;
+    i2cBuff[3] = baro & 255;
+    i2cBuff[4] = scd30::calcCrc2b(baro);
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 5, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Stop auto-measurement
+
+uint8_t scd30::stopMeasurement()
+{
+    i2cBuff[0] = SCD30_CMMD_STOP_CONT_MEAS >> 8;
+    i2cBuff[1] = SCD30_CMMD_STOP_CONT_MEAS & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Change the measurement interval (in Secs), 
+
+uint8_t scd30::setMeasInterval(uint16_t mi)
+{
+    i2cBuff[0] = SCD30_CMMD_SET_MEAS_INTVL >> 8;
+    i2cBuff[1] = SCD30_CMMD_SET_MEAS_INTVL & 255;
+    i2cBuff[2] = mi >> 8;
+    i2cBuff[3] = mi & 255;
+    i2cBuff[4] = scd30::calcCrc2b(mi);
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 5, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Get ready status value
+
+uint8_t scd30::getReadyStatus(SCD30_str& sSTR)
+{
+    i2cBuff[0] = SCD30_CMMD_GET_READY_STAT >> 8;
+    i2cBuff[1] = SCD30_CMMD_GET_READY_STAT & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    
+    _i2c.read(SCD30_I2C_ADDR | 1, i2cBuff, 3, false);
+    uint16_t stat = (i2cBuff[0] << 8) | i2cBuff[1];
+    sSTR.ready = stat;
+    uint8_t dat = scd30::checkCrc2b(stat, i2cBuff[2]);
+    
+    if(dat == SCDcrcERROR) return SCDcrcERRORv1;
+    if(dat == SCDisReady) return SCDisReady;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Get all the measurement values, stick them into the array
+
+uint8_t scd30::readMeasurement(SCD30_str& sSTR)
+{
+    i2cBuff[0] = SCD30_CMMD_READ_MEAS >> 8;
+    i2cBuff[1] = SCD30_CMMD_READ_MEAS & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    
+    _i2c.read(SCD30_I2C_ADDR | 1, i2cBuff, 18, false);
+    
+    uint16_t stat = (i2cBuff[0] << 8) | i2cBuff[1];
+    sSTR.co2m = stat;
+    uint8_t dat = scd30::checkCrc2b(stat, i2cBuff[2]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv1;
+    
+    stat = (i2cBuff[3] << 8) | i2cBuff[4];
+    sSTR.co2l = stat;
+    dat = scd30::checkCrc2b(stat, i2cBuff[5]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv2;
+    
+    stat = (i2cBuff[6] << 8) | i2cBuff[7];
+    sSTR.tempm = stat;
+    dat = scd30::checkCrc2b(stat, i2cBuff[8]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv3;
+    
+    stat = (i2cBuff[9] << 8) | i2cBuff[10];
+    sSTR.templ = stat;
+    dat = scd30::checkCrc2b(stat, i2cBuff[11]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv4;
+    
+    stat = (i2cBuff[12] << 8) | i2cBuff[13];
+    sSTR.humm = stat;
+    dat = scd30::checkCrc2b(stat, i2cBuff[14]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv5;
+    
+    stat = (i2cBuff[15] << 8) | i2cBuff[16];
+    sSTR.huml = stat;
+    dat = scd30::checkCrc2b(stat, i2cBuff[17]);
+    if(dat == SCDcrcERROR) return SCDcrcERRORv6;
+    
+    sSTR.co2i = (sSTR.co2m << 16) | sSTR.co2l ;
+    sSTR.tempi = (sSTR.tempm << 16) | sSTR.templ ;
+    sSTR.humi = (sSTR.humm << 16) | sSTR.huml ;
+    
+    sSTR.co2f = *(float*)&sSTR.co2i;
+    sSTR.tempf = *(float*)&sSTR.tempi;
+    sSTR.humf = *(float*)&sSTR.humi;
+    
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Change the ambient temperature (in 0.01C), 
+//   i.e. 0x1F4 = 500 = 5.00C, CRC = 0x33
+
+uint8_t scd30::setTemperatureOffs(uint16_t temp)
+{
+    i2cBuff[0] = SCD30_CMMD_SET_TEMP_OFFS >> 8;
+    i2cBuff[1] = SCD30_CMMD_SET_TEMP_OFFS & 255;
+    i2cBuff[2] = temp >> 8;
+    i2cBuff[3] = temp & 255;
+    i2cBuff[4] = scd30::calcCrc2b(temp);
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 5, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Change the altitude reading (in meters above seal level)
+
+uint8_t scd30::setAltitudeComp(uint16_t alt)
+{
+    i2cBuff[0] = SCD30_CMMD_SET_ALT_COMP >> 8;
+    i2cBuff[1] = SCD30_CMMD_SET_ALT_COMP & 255;
+    i2cBuff[2] = alt >> 8;
+    i2cBuff[3] = alt & 255;
+    i2cBuff[4] = scd30::calcCrc2b(alt);
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 5, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Perform a soft reset on the SCD30
+
+uint8_t scd30::softReset()
+{
+    i2cBuff[0] = SCD30_CMMD_SOFT_RESET >> 8;
+    i2cBuff[1] = SCD30_CMMD_SOFT_RESET & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+    
+//-----------------------------------------------------------------------------
+// Calculate the CRC of a 2 byte value using the SCD30 CRC polynomial
+
+uint8_t scd30::calcCrc2b(uint16_t seed)
+{
+  uint8_t bit;                  // bit mask
+  uint8_t crc = SCD30_CRC_INIT; // calculated checksum
+  
+  // calculates 8-Bit checksum with given polynomial
+
+    crc ^= (seed >> 8) & 255;
+    for(bit = 8; bit > 0; --bit)
+    {
+      if(crc & 0x80) crc = (crc << 1) ^ SCD30_POLYNOMIAL;
+      else           crc = (crc << 1);
+    }
+
+    crc ^= seed & 255;
+    for(bit = 8; bit > 0; --bit)
+    {
+      if(crc & 0x80) crc = (crc << 1) ^ SCD30_POLYNOMIAL;
+      else           crc = (crc << 1);
+    }
+    
+  return crc;
+}
+
+//-----------------------------------------------------------------------------
+// Compare the CRC values
+
+uint8_t scd30::checkCrc2b(uint16_t seed, uint8_t crcIn)
+{
+    uint8_t crcCalc = scd30::calcCrc2b(seed);
+    if(crcCalc != crcIn) return SCDcrcERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// start single-measurement with barometer reading (in mB)
+//
+
+uint8_t scd30::startOneMeasurement(uint16_t baro)
+{
+    i2cBuff[0] = SCD30_CMMD_START_SINGLE_MEAS >> 8;
+    i2cBuff[1] = SCD30_CMMD_START_SINGLE_MEAS & 255;
+    i2cBuff[2] = baro >> 8;
+    i2cBuff[3] = baro & 255;
+    i2cBuff[4] = scd30::calcCrc2b(baro);
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 5, false);
+    if(res) return SCDnoAckERROR;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Get article code
+
+uint8_t scd30::getArticleCode(SCD30_str& sSTR)
+{
+    i2cBuff[0] = SCD30_CMMD_READ_ARTICLECODE >> 8;
+    i2cBuff[1] = SCD30_CMMD_READ_ARTICLECODE & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    
+    _i2c.read(SCD30_I2C_ADDR | 1, i2cBuff, 3, false);
+    uint16_t stat = (i2cBuff[0] << 8) | i2cBuff[1];
+    sSTR.acode = stat;
+    uint8_t dat = scd30::checkCrc2b(stat, i2cBuff[2]);
+    
+    if(dat == SCDcrcERROR) return SCDcrcERRORv1;
+    return SCDnoERROR;
+}
+
+//-----------------------------------------------------------------------------
+// Get scd30 serial number
+
+uint8_t scd30::getSerialNumber(SCD30_str& sSTR)
+{
+    i2cBuff[0] = SCD30_CMMD_READ_SERIALNBR >> 8;
+    i2cBuff[1] = SCD30_CMMD_READ_SERIALNBR & 255;
+    int res = _i2c.write(SCD30_I2C_ADDR, i2cBuff, 2, false);
+    if(res) return SCDnoAckERROR;
+    
+    int i = 0;
+    for(i = 0; i < sizeof(sSTR.sn); i++) sSTR.sn[i] = 0;
+    for(i = 0; i < sizeof(i2cBuff); i++) i2cBuff[i] = 0;
+    
+    _i2c.read(SCD30_I2C_ADDR | 1, i2cBuff, SCD30_SN_SIZE, false);
+    int t = 0;
+    for(i = 0; i < SCD30_SN_SIZE; i +=3) {
+        uint16_t stat = (i2cBuff[i] << 8) | i2cBuff[i + 1];
+        sSTR.sn[i - t] = stat >> 8;
+        sSTR.sn[i - t + 1] = stat & 255;
+        uint8_t dat = scd30::checkCrc2b(stat, i2cBuff[i + 2]);
+        t++;
+        if(dat == SCDcrcERROR) return SCDcrcERRORv1;
+        if(stat == 0) break;
+    }
+
+    return SCDnoERROR;
+}