I2C Temprature Sensor Progemm MPL3115A2
Dependents: I2C_Temprature_raspiboard
Fork of MPL3115A2 by
Diff: MPL3115A2.cpp
- Revision:
- 0:beb43bc3d6d4
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MPL3115A2.cpp Tue Apr 01 21:35:23 2014 +0000 @@ -0,0 +1,219 @@ +#include "MPL3115A2.h" +#include "mbed.h" + +#include "stdarg.h" // For debugOut use of the ... parameter and va_list + +MPL3115A2::MPL3115A2(I2C *i2c, Serial *pc) : _i2c(i2c), _debug(pc) +{ +} + +// By default I set the sensor to altimeter mode. I inserted a 1ms pause +// between each call to allow logic capture if needed. This give a small +// gap between captures on the bus to make working with the data easier. +void MPL3115A2::init() +{ + setModeStandby(); + wait_ms(1); + setModeAltimeter(); + wait_ms(1); + setOversampleRate(7); + wait_ms(1); + enableEventFlags(); + wait_ms(1); + setModeActive(); + wait_ms(1); +} + +// This method wait for a specified amount of time for one of the data +// ready flags to be set. You need to pass in the correct data ready +// mask for this to work. See page 22 of the datasheet. +int MPL3115A2::dataReady(const char mask) +{ + int attempts = 0; + + while ((i2cRead(STATUS) & mask) == 0) + { + attempts++; + + if(attempts > MAX_DATA_READY_ATTEMPTS) + return 0; // Failed + + wait_ms(1); + } + + return 1; // Success +} + +Altitude* MPL3115A2::readAltitude(Altitude* a) +{ + // Force the sensor to take a new reading. + toggleOneShot(); + + // Wait for the data to be ready. + if (!pressureDataReady()) + { + debugOut("MPL3115A2::readAltitude: Sensor failed to generate an altitude reading in a reasonable time.\r\n"); + + // We leave the altitude object as is if we encounter an error. + return a; + } + + // Get the new data from the sensor. + _i2c->start(); // Start + if (_i2c->write(MPL3115A2_ADDRESS) != 1) // A write to device + debugOut("MPL3115A2::readAltitude: Sensor failed to respond to write request at address 0x%X\r\n", MPL3115A2_ADDRESS); + + if (_i2c->write(OUT_P_MSB) != 1) // Register to read + debugOut("MPL3115A2::readAltitude: Sensor at address 0x%X did not acknowledge register 0x%X\r\n", MPL3115A2_ADDRESS, OUT_P_MSB); + + // Write the data directly into our Altitude object. This object + // takes care of converting the compressed data from the sensor, and + // provides functions to get the data in various units. And it also + // has a print function to output the data as a string. + _i2c->read(MPL3115A2_ADDRESS, (*a), Altitude::size); + a->setAltitude(); + + return a; +} + +// See readAltitude for comments about this function. +Pressure* MPL3115A2::readPressure(Pressure* p) +{ + toggleOneShot(); + + if (!pressureDataReady()) + { + debugOut("MPL3115A2::readPressure: Sensor failed to generate a pressure reading in a reasonable time.\r\n"); + return p; + } + + _i2c->start(); + if (_i2c->write(MPL3115A2_ADDRESS) != 1) + debugOut("MPL3115A2::readPressure: Sensor failed to respond to write request at address 0x%X\r\n", MPL3115A2_ADDRESS); + + if (_i2c->write(OUT_P_MSB) != 1) + debugOut("MPL3115A2::readPressure: Sensor at address 0x%X did not acknowledge register 0x%X\r\n", MPL3115A2_ADDRESS, OUT_P_MSB); + + _i2c->read(MPL3115A2_ADDRESS, (*p), Pressure::size); + p->setPressure(); + + return p; +} + +// See readAltitude for comments about this function. +Temperature* MPL3115A2::readTemperature(Temperature* t) +{ + toggleOneShot(); + + if (!temperatureDataReady()) + { + debugOut("MPL3115A2::readTemperature: Sensor failed to generate a temperature reading in a reasonable time.\r\n"); + return t; + } + + _i2c->start(); + if (_i2c->write(MPL3115A2_ADDRESS) != 1) + debugOut("MPL3115A2::readTemperature: Sensor failed to respond to write request at address 0x%X\r\n", MPL3115A2_ADDRESS); + + if (_i2c->write(OUT_T_MSB) != 1) + debugOut("MPL3115A2::readTemperature: Sensor at address 0x%X did not acknowledge register 0x%X\r\n", MPL3115A2_ADDRESS, OUT_P_MSB); + + _i2c->read(MPL3115A2_ADDRESS, (*t), Temperature::size); + t->setTemperature(); + + return t; +} + +void MPL3115A2::setModeAltimeter() +{ + setRegisterBit(CTRL_REG1, 0x80); // Set ALT bit +} + +void MPL3115A2::setModeBarometer() +{ + clearRegisterBit(CTRL_REG1, 0x80); // Clear ALT bit +} + +void MPL3115A2::setModeStandby() +{ + clearRegisterBit(CTRL_REG1, 0x01); // Clear SBYB bit for Standby mode +} +void MPL3115A2::setModeActive() +{ + setRegisterBit(CTRL_REG1, 0x01); // Set SBYB bit for Active mode +} + +void MPL3115A2::setOversampleRate(char sampleRate) +{ + if(sampleRate > 7) + sampleRate = 7; // OS cannot be larger than 0b.0111 + + sampleRate <<= 3; // Align it for the CTRL_REG1 register + + char temp = i2cRead(CTRL_REG1); // Read current settings + temp &= 0xC7; // Clear out old OS bits + temp |= sampleRate; // Mask in new OS bits + i2cWrite(CTRL_REG1, temp); +} + +void MPL3115A2::enableEventFlags() +{ + i2cWrite(PT_DATA_CFG, 0x07); // Enable all three pressure and temp event flags +} + +void MPL3115A2::toggleOneShot(void) +{ + clearRegisterBit(CTRL_REG1, 0x02); // Clear OST bit + setRegisterBit(CTRL_REG1, 0x02); // Set the OST bit. +} + +void MPL3115A2::clearRegisterBit(const char regAddr, const char bitMask) +{ + char temp = i2cRead(regAddr); // Read the current register value + temp &= ~bitMask; // Clear the bit from the value + i2cWrite(regAddr, temp); // Write register value back +} + +void MPL3115A2::setRegisterBit(const char regAddr, const char bitMask) +{ + char temp = i2cRead(regAddr); // Read the current register value + temp |= bitMask; // Set the bit in the value + i2cWrite(regAddr, temp); // Write register value back +} + +char MPL3115A2::i2cRead(char regAddr) +{ + _i2c->start(); // Start + if (_i2c->write(MPL3115A2_ADDRESS)!=1) // A write to device + debugOut("MPL3115A2::i2cRead: Sensor failed to respond to write request at address 0x%X\r\n", MPL3115A2_ADDRESS); + + if (_i2c->write(regAddr)!=1) // Register to read + debugOut("MPL3115A2::i2cRead: Sensor at address 0x%X did not acknowledge register 0x%X\r\n", MPL3115A2_ADDRESS, regAddr); + + _i2c->start(); + if (_i2c->write(MPL3115A2_ADDRESS|0x01)!=1) // Read from device + debugOut("MPL3115A2::i2cRead: Sensor failed to respond to read request at address 0x%X\r\n", MPL3115A2_ADDRESS); + + char result = _i2c->read(READ_NAK); // Read the data + _i2c->stop(); + + return result; +} + +void MPL3115A2::i2cWrite(char regAddr, char value) +{ + char cmd[2]; + cmd[0] = regAddr; + cmd[1] = value; + if (_i2c->write(MPL3115A2_ADDRESS, cmd, 2) != 0) + debugOut("MPL3115A2::i2cWrite: Failed writing value (%d, 0x%X) to register 0x%X\r\n", value, regAddr); +} + +void MPL3115A2::debugOut(const char * format, ...) +{ + if (_debug == NULL) + return; + + va_list arg; + _debug->printf(format, arg); +}