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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1993 | - | 1 | /* |
| 2 | MS5611-01BA.cpp - Interfaces a Measurement Specialities MS5611-01BA with Arduino |
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| 3 | See http://www.meas-spec.com/downloads/MS5611-01BA01.pdf for the device datasheet |
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| 4 | |||
| 5 | Copyright (C) 2011 Fabio Varesano <fvaresano@yahoo.it> |
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| 6 | |||
| 7 | Development of this code has been supported by the Department of Computer Science, |
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| 8 | Universita' degli Studi di Torino, Italy within the Piemonte Project |
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| 9 | http://www.piemonte.di.unito.it/ |
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| 10 | |||
| 11 | |||
| 12 | This program is free software: you can redistribute it and/or modify |
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| 13 | it under the terms of the version 3 GNU General Public License as |
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| 14 | published by the Free Software Foundation. |
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| 15 | |||
| 16 | This program is distributed in the hope that it will be useful, |
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| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 19 | GNU General Public License for more details. |
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| 20 | |||
| 21 | You should have received a copy of the GNU General Public License |
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| 22 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
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| 23 | |||
| 24 | */ |
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| 25 | |||
| 26 | #include "MS561101BA.h" |
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| 27 | #define EXTRA_PRECISION 5 // trick to add more precision to the pressure and temp readings |
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| 28 | |||
| 29 | MS561101BA::MS561101BA() { |
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| 30 | ; |
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| 31 | } |
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| 32 | |||
| 33 | void MS561101BA::init(uint8_t address) { |
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| 34 | _addr = address; |
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| 35 | |||
| 36 | // disable internal pullups of the ATMEGA which Wire enable by default |
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| 37 | #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) |
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| 38 | // deactivate internal pull-ups for twi |
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| 39 | // as per note from atmega8 manual pg167 |
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| 40 | cbi(PORTC, 4); |
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| 41 | cbi(PORTC, 5); |
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| 42 | #else |
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| 43 | // deactivate internal pull-ups for twi |
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| 44 | // as per note from atmega128 manual pg204 |
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| 45 | cbi(PORTD, 0); |
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| 46 | cbi(PORTD, 1); |
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| 47 | #endif |
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| 48 | |||
| 49 | reset(); // reset the device to populate its internal PROM registers |
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| 50 | delay(1000); // some safety time |
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| 51 | readPROM(); // reads the PROM into object variables for later use |
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| 52 | } |
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| 53 | |||
| 54 | float MS561101BA::getPressure(uint8_t OSR) { |
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| 55 | // see datasheet page 7 for formulas |
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| 56 | int64_t dT = getDeltaTemp(OSR); |
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| 57 | int64_t off = (((int64_t)_C[1]) << 16) + ((_C[3] * dT) >> 7); |
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| 58 | int64_t sens = (((int64_t)_C[0]) << 15) + ((_C[2] * dT) >> 8); |
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| 59 | return ((((rawPressure(OSR) * sens) >> 21) - off) >> (15-EXTRA_PRECISION)) / ((1<<EXTRA_PRECISION) * 100.0); |
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| 60 | } |
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| 61 | |||
| 62 | float MS561101BA::getTemperature(uint8_t OSR) { |
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| 63 | // see datasheet page 7 for formulas |
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| 64 | return ((1<<EXTRA_PRECISION)*2000l + ((getDeltaTemp(OSR) * _C[5]) >> (23-EXTRA_PRECISION))) / ((1<<EXTRA_PRECISION) * 100.0); |
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| 65 | } |
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| 66 | |||
| 67 | int64_t MS561101BA::getDeltaTemp(uint8_t OSR) { |
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| 68 | return rawTemperature(OSR) - (((int32_t)_C[4]) << 8); |
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| 69 | } |
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| 70 | |||
| 71 | int32_t MS561101BA::rawPressure(uint8_t OSR) { |
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| 72 | return doConversion(MS561101BA_D1 + OSR); |
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| 73 | } |
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| 74 | |||
| 75 | int32_t MS561101BA::rawTemperature(uint8_t OSR) { |
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| 76 | return doConversion(MS561101BA_D2 + OSR); |
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| 77 | } |
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| 78 | |||
| 79 | |||
| 80 | unsigned long MS561101BA::doConversion(uint8_t command) { |
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| 81 | unsigned long conversion = 0; |
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| 82 | |||
| 83 | // see page 11 of the datasheet |
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| 84 | |||
| 85 | // initialize pressure conversion |
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| 86 | Wire.beginTransmission(_addr); |
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| 87 | Wire.send(command); |
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| 88 | Wire.endTransmission(); |
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| 89 | |||
| 90 | delay(10); // the conversion will take a time <= 9.04 ms to have the output ready |
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| 91 | // TODO: make the delay dependant on the OSR requested in the command |
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| 92 | |||
| 93 | // start read sequence |
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| 94 | Wire.beginTransmission(_addr); |
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| 95 | Wire.send(0); |
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| 96 | Wire.endTransmission(); |
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| 97 | |||
| 98 | Wire.beginTransmission(_addr); |
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| 99 | Wire.requestFrom(_addr, (uint8_t) MS561101BA_D1D2_SIZE); |
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| 100 | if(Wire.available()) { |
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| 101 | conversion = Wire.receive() * 65536 + Wire.receive() * 256 + Wire.receive(); |
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| 102 | } |
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| 103 | else { |
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| 104 | conversion = -1; |
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| 105 | } |
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| 106 | |||
| 107 | return conversion; |
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| 108 | } |
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| 109 | |||
| 110 | |||
| 111 | /** |
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| 112 | * Reads factory calibration and store it into object variables. |
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| 113 | */ |
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| 114 | int MS561101BA::readPROM() { |
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| 115 | for (int i=0;i<MS561101BA_PROM_REG_COUNT;i++) { |
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| 116 | Wire.beginTransmission(_addr); |
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| 117 | Wire.send(MS561101BA_PROM_BASE_ADDR + (i * MS561101BA_PROM_REG_SIZE)); |
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| 118 | Wire.endTransmission(); |
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| 119 | |||
| 120 | Wire.beginTransmission(_addr); |
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| 121 | Wire.requestFrom(_addr, (uint8_t) MS561101BA_PROM_REG_SIZE); |
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| 122 | if(Wire.available()) { |
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| 123 | _C[i] = Wire.receive() << 8 | Wire.receive(); |
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| 124 | |||
| 125 | //DEBUG_PRINT(_C[i]); |
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| 126 | } |
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| 127 | else { |
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| 128 | return -1; // error reading the PROM or communicating with the device |
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| 129 | } |
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| 130 | } |
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| 131 | return 0; |
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| 132 | } |
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| 133 | |||
| 134 | |||
| 135 | /** |
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| 136 | * Send a reset command to the device. With the reset command the device |
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| 137 | * populates its internal registers with the values read from the PROM. |
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| 138 | */ |
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| 139 | void MS561101BA::reset() { |
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| 140 | Wire.beginTransmission(_addr); |
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| 141 | Wire.send(MS561101BA_RESET); |
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| 142 | Wire.endTransmission(); |
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| 143 | } |