mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-09-19 16:46:11 -04:00
301 lines
6.7 KiB
C++
301 lines
6.7 KiB
C++
//
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// FILE: MS5611.cpp
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// AUTHOR: Rob Tillaart
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// Erni - testing/fixes
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// VERSION: 0.4.0
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// PURPOSE: Arduino library for MS5611 temperature and pressure sensor
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// URL: https://github.com/RobTillaart/MS5611
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//
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// HISTORY see changelog.md
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#include "MS5611.h"
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// datasheet page 10
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#define MS5611_CMD_READ_ADC 0x00
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#define MS5611_CMD_READ_PROM 0xA0
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#define MS5611_CMD_RESET 0x1E
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#define MS5611_CMD_CONVERT_D1 0x40
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#define MS5611_CMD_CONVERT_D2 0x50
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/////////////////////////////////////////////////////
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//
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// PUBLIC
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//
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MS5611::MS5611(uint8_t deviceAddress, TwoWire * wire)
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{
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_address = deviceAddress;
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_wire = wire;
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_samplingRate = OSR_ULTRA_LOW;
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_temperature = MS5611_NOT_READ;
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_pressure = MS5611_NOT_READ;
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_result = MS5611_NOT_READ;
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_lastRead = 0;
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_deviceID = 0;
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_pressureOffset = 0;
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_temperatureOffset = 0;
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_compensation = true;
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}
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bool MS5611::begin()
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{
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if ((_address < 0x76) || (_address > 0x77)) return false;
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if (! isConnected()) return false;
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return reset();
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}
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bool MS5611::isConnected()
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{
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_wire->beginTransmission(_address);
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#ifdef ARDUINO_ARCH_NRF52840
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// needed for NANO 33 BLE
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_wire->write(0);
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#endif
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return (_wire->endTransmission() == 0);
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}
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bool MS5611::reset(uint8_t mathMode)
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{
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command(MS5611_CMD_RESET);
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uint32_t start = micros();
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// while loop prevents blocking RTOS
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while (micros() - start < 2800)
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{
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yield();
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delayMicroseconds(10);
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}
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// initialize the C[] array
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initConstants(mathMode);
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// read factory calibrations from EEPROM.
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bool ROM_OK = true;
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for (uint8_t reg = 0; reg < 7; reg++)
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{
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// used indices match datasheet.
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// C[0] == manufacturer - read but not used;
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// C[7] == CRC - skipped.
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uint16_t tmp = readProm(reg);
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C[reg] *= tmp;
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// _deviceID is a SHIFT XOR merge of 7 PROM registers, reasonable unique
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_deviceID <<= 4;
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_deviceID ^= tmp;
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// Serial.println(readProm(reg));
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if (reg > 0)
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{
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ROM_OK = ROM_OK && (tmp != 0);
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}
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}
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return ROM_OK;
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}
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int MS5611::read(uint8_t bits)
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{
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// VARIABLES NAMES BASED ON DATASHEET
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// ALL MAGIC NUMBERS ARE FROM DATASHEET
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convert(MS5611_CMD_CONVERT_D1, bits);
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if (_result) return _result;
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// NOTE: D1 and D2 seem reserved in MBED (NANO BLE)
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uint32_t _D1 = readADC();
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if (_result) return _result;
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convert(MS5611_CMD_CONVERT_D2, bits);
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if (_result) return _result;
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uint32_t _D2 = readADC();
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if (_result) return _result;
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// Serial.println(_D1);
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// Serial.println(_D2);
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// TEST VALUES - comment lines above
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// uint32_t _D1 = 9085466;
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// uint32_t _D2 = 8569150;
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// TEMP & PRESS MATH - PAGE 7/20
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float dT = _D2 - C[5];
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_temperature = 2000 + dT * C[6];
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float offset = C[2] + dT * C[4];
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float sens = C[1] + dT * C[3];
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if (_compensation)
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{
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// SECOND ORDER COMPENSATION - PAGE 8/20
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// COMMENT OUT < 2000 CORRECTION IF NOT NEEDED
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// NOTE TEMPERATURE IS IN 0.01 C
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if (_temperature < 2000)
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{
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float T2 = dT * dT * 4.6566128731E-10;
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float t = (_temperature - 2000) * (_temperature - 2000);
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float offset2 = 2.5 * t;
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float sens2 = 1.25 * t;
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// COMMENT OUT < -1500 CORRECTION IF NOT NEEDED
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if (_temperature < -1500)
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{
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t = (_temperature + 1500) * (_temperature + 1500);
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offset2 += 7 * t;
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sens2 += 5.5 * t;
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}
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_temperature -= T2;
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offset -= offset2;
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sens -= sens2;
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}
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// END SECOND ORDER COMPENSATION
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}
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_pressure = (_D1 * sens * 4.76837158205E-7 - offset) * 3.051757813E-5;
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_lastRead = millis();
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return MS5611_READ_OK;
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}
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void MS5611::setOversampling(osr_t samplingRate)
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{
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_samplingRate = (uint8_t) samplingRate;
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}
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float MS5611::getTemperature() const
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{
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if (_temperatureOffset == 0) return _temperature * 0.01;
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return _temperature * 0.01 + _temperatureOffset;
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};
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float MS5611::getPressure() const
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{
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if (_pressureOffset == 0) return _pressure * 0.01;
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return _pressure * 0.01 + _pressureOffset;
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};
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// EXPERIMENTAL
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uint16_t MS5611::getManufacturer()
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{
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return readProm(0);
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}
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// EXPERIMENTAL
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uint16_t MS5611::getSerialCode()
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{
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return readProm(7) >> 4;
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}
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/////////////////////////////////////////////////////
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//
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// PRIVATE
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//
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void MS5611::convert(const uint8_t addr, uint8_t bits)
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{
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// values from page 3 datasheet - MAX column (rounded up)
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uint16_t del[5] = {600, 1200, 2300, 4600, 9100};
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uint8_t index = bits;
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if (index < 8) index = 8;
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else if (index > 12) index = 12;
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index -= 8;
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uint8_t offset = index * 2;
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command(addr + offset);
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uint16_t waitTime = del[index];
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uint32_t start = micros();
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// while loop prevents blocking RTOS
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while (micros() - start < waitTime)
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{
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yield();
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delayMicroseconds(10);
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}
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}
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uint16_t MS5611::readProm(uint8_t reg)
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{
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// last EEPROM register is CRC - Page 13 datasheet.
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uint8_t promCRCRegister = 7;
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if (reg > promCRCRegister) return 0;
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uint8_t offset = reg * 2;
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command(MS5611_CMD_READ_PROM + offset);
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if (_result == 0)
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{
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uint8_t length = 2;
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int bytes = _wire->requestFrom(_address, length);
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if (bytes >= length)
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{
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uint16_t value = _wire->read() * 256;
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value += _wire->read();
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return value;
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}
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return 0;
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}
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return 0;
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}
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uint32_t MS5611::readADC()
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{
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command(MS5611_CMD_READ_ADC);
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if (_result == 0)
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{
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uint8_t length = 3;
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int bytes = _wire->requestFrom(_address, length);
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if (bytes >= length)
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{
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uint32_t value = _wire->read() * 65536UL;
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value += _wire->read() * 256UL;
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value += _wire->read();
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return value;
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}
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return 0UL;
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}
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return 0UL;
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}
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int MS5611::command(const uint8_t command)
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{
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yield();
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_wire->beginTransmission(_address);
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_wire->write(command);
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_result = _wire->endTransmission();
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return _result;
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}
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void MS5611::initConstants(uint8_t mathMode)
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{
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// constants that were multiplied in read() - datasheet page 8
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// do this once and you save CPU cycles
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//
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// datasheet ms5611 | appNote
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// mode = 0; | mode = 1
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C[0] = 1;
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C[1] = 32768L; // SENSt1 = C[1] * 2^15 | * 2^16
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C[2] = 65536L; // OFFt1 = C[2] * 2^16 | * 2^17
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C[3] = 3.90625E-3; // TCS = C[3] / 2^8 | / 2^7
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C[4] = 7.8125E-3; // TCO = C[4] / 2^7 | / 2^6
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C[5] = 256; // Tref = C[5] * 2^8 | * 2^8
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C[6] = 1.1920928955E-7; // TEMPSENS = C[6] / 2^23 | / 2^23
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if (mathMode == 1) // Appnote version for pressure.
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{
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C[1] = 65536L; // SENSt1
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C[2] = 131072L; // OFFt1
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C[3] = 7.8125E-3; // TCS
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C[4] = 1.5625e-2; // TCO
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}
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}
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// -- END OF FILE --
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