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# MS5611

Arduino library for MS5611 temperature and pressure sensor.


## Description

The MS5611 is a high resolution temperature and pressure sensor.
The high resolution is made possible by oversampling (many times).

The device address is 0x76 or 0x77 depending on the CSB pin.


#### 0.3.0 breaking changes

1. fixed math error so previous versions are **obsolete**.
2. temperature is a float expressed in degrees Celsius.
3. pressure is a float expressed in mBar.


## Interface

- **MS5611(uint8_t deviceAddress)** constructor.
- **bool begin(uint8_t sda, uint8_t scl, TwoWire \*wire = &Wire)** for ESP and alike, optionally set Wire interface. initializes internals, 
- **bool begin(TwoWire \*wire = &Wire)** for UNO and alike, optionally set Wire interface. Initializes internals.
- **bool isConnected()** checks availability of device address on the I2C bus.
- **reset()** resets the chip and loads constants from its ROM.
- **int read(uint8_t bits)** the actual reading of the sensor. Returns MS5611_READ_OK upon success.
- **int read()** the actual reading of the sensor. Returns MS5611_READ_OK upon success.
- **void setOversampling(osr_t samplingRate)** sets the amount of oversampling. 
See table below and test example how to use.
- **osr_t getOversampling()** returns amount of oversampling.
- **float getTemperature()** returns temperature in °C. Subsequent calls will return same value until a new **read()** is called.
- **float getPressure()** pressure is in mBar. Subsequent calls will return same value until a new **read()** is called.
- **int getLastResult()** checks last I2C communication (replace with more informative error handling?)
- **uint32_t lastRead()** last time when **read()** was called in millis() since startup.


#### Oversampling table

| definition     | value | oversampling ratio | resolution (mbar) | time (ms) | notes |
|:--------------:|:-----:|:------------------:|:----------------:|:---------:|:------:|
| OSR_ULTRA_HIGH |  12   |        4096        |      0.012       |   8.22    |
| OSR_HIGH       |  11   |        2048        |      0.018       |   4.1     |
| OSR_STANDARD   |  10   |        1024        |      0.027       |   2.1     |
| OSR_LOW        |  9    |        512         |      0.042       |   1.1     |
| OSR_ULTRA_LOW  |  8    |        256         |      0.065       |   0.5     | Default = backwards compatible


## Disclaimer

The library is experimental. As I have no such sensor the quality is hard to test.
So if you happen to have such a sensor, please give it a try and let me know.


## Operation

See examples


## Future

- get such a sensor to test
- update documentation
- create a SPI based library (same base class if possible?)
- proper error handling
- redo lower level functions?
- handle the read + math of temperature first? (need hardware to test)
-