GY-63_MS5611/libraries/I2C_ASDX/README.md

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# I2C_ASDX

Arduino library for I2C ASDX pressure sensor.


## Description

The ASDX sensor of Honeywell exist in many variations.
Check the datasheet of your type for all the details.

The I2C_ASDX library can read the sensor and give the pressure in millibar, 
bar or PSI or many other units. See below.

#### Links

Related library: https://github.com/RobTillaart/pressure


#### Hardware connection

Always check datasheet for the exact pins.

```
        ASDX              ARDUINO
    +----------+        +----------+
    |          |        |          |
    |     GND o|--------|o GND     |
    |     VCC o|--------|o VCC     |
    |     SDA o|--------|o SDA     |
    |     SCL o|--------|o SCL     |
    |          |        |          |
    +----------+        +----------+
```


## Interface

```cpp
#include "I2C_ASDX.h"
```


#### Constructor

- **I2C_ASDX(uint8_taddress, uint8_t psi, TwoWire \*wire = &Wire)** Constructor, 
I2C address and maximum pressure. Optional the wire interface can be defined.
- **bool begin(uint8_t sda, uint8_t scl)** I2C parameters for ESP32 a.o. 
Returns true if address can be found  on I2C bus.
- **bool begin()** for UNO and other boards supporting Wire. 
Returns true if address can be found  on I2C bus.
- **void reset()** resets internal variables, including pressure.
- **bool isConnected()** tests if address can be found on I2C bus.
- **uint8_t getAddress()** returns I2C address used.
Mainly for debug message.


#### Read

Before any call to **getPressure()** one need to call **read()** unless one wants the last value read.

- **int read()** actually reads the sensor, checks for errors, 
calculates the pressure and set the lastRead timestamp. 
Returns **I2C_ASDX_OK** or an error code.


#### Units

- **int getPressure()** returns pressure in milliBar.
(rounded integer!).
Returns 0 after a reset() and no read() done yet.
Calling **getPressure()** (Or any of the other pressure functions) multiple times 
without read() will return the same value again.
- **float getMilliBar()** returns pressure in milliBar (float).
- **float getBar()** returns pressure in bar.
- **float getPSI()** returns pressure in PSI = Pounds per Square Inch.
- **float getATM()** returns pressure in Atmosphere.
- **float getDynes()** returns pressure in Dynes.
- **float getInchHg()** returns pressure in inches mercury.
- **float getInchH2O()** returns pressure in inches water.
- **float getPascal()** returns pressure in Pascal. Note this is the SI unit.
- **float getTORR()** returns pressure in TORR.
- **float getCmHg()** returns pressure in centimetre mercury.
- **float getCmH2O()** returns pressure in centimetre water.
- **float getMSW()** returns pressure in Meters of Sea Water. (under water pressure unit).

Related library: https://github.com/RobTillaart/pressure


#### State

- **uint16_t errorCount()** total counter for the number of errors occurred.
- **uint32_t lastRead()** time in milliseconds of last successful read of the sensor.
- **int state()** last known state of read, also returned by **read()**

|  state                   |  meaning             |
|:-------------------------|:---------------------|
|  I2C_ASDX_OK             |  no error            |
|  I2C_ASDX_INIT           |  begin() not called  |
|  I2C_ASDX_READ_ERROR     |  I2C error           |
|  I2C_ASDX_C000_ERROR     |  sensor error        |
|  I2C_ASDX_CONNECT_ERROR  |  I2C error           |


## Testing

The library is tested with only 3 different sensors, all of the PG type.

Code is prepared but not tested for 15, 5 and 1 PSI too.

```
    ID    UNIT       TYPE   DESCRIPTION
                              output is proportional to difference
    PG    PSI        Gage   * between applied pressure and atmospheric pressure
    MG    mBar       Gage   * idem
    BG    Bar        Gage   * idem
    KG    KiloPascal Gage   * idem
     D    Differential      * between pressure applied to each of the ports.
     A    Absolute          * between applied pressure and built-in reference to vacuum.


    ADDRESS   PRESSURE   RANGE          TYPE      P   A T V
    0x58      100 psi    0..6895 mBar   SSCDANN 100PG 5 A 5
    0x38       60 psi    0..4137 mbar   SSCDANN 060PG 3 A 5
    0x28       30 psi    0..2068 mbar   SSCDANN 030PG 2 A 5

    P = pressure range
    A = I2C address indicator
    T = accuracy range
    V = voltage (3 volt also supported, not tested)
```

That said it is expected that the library is modifiable to support many
more as long as they have the following raw read values.

```
    1638  =   0 PSI
    14746 = max PSI
```


## Tested types

|  Type number        |  result  |  notes  |
|:--------------------|:--------:|:--------|
|  SSCDANN 100PG 5A5  |    OK    |  type A 10% - 90% only
|  SSCDANN 060PG 3A5  |    OK    |
|  SSCDANN 030PG 2A5  |    OK    |

(elaborate test table)


## Operation

See examples


## Future

#### Must

- update documentation.


#### Should

- add real life examples if possible.
- add error/state code for after reset() and before read()
  - I2C_ASDX_NO_READ or I2C_ASDX_RESET


#### Could

- remove less common pressure formats from lib (0.4.0 ?)
  - are covered in pressure lib.
  - but they do no harm either.
- move code from .h to .cpp
- **getPressure()** obsolete ? 
  - **getMillibar()**  ==> 0.4.0 ??
- find a good reference for conversion formula constants.


#### Wont


## Support

If you appreciate my libraries, you can support the development and maintenance.
Improve the quality of the libraries by providing issues and Pull Requests, or
donate through PayPal or GitHub sponsors.

Thank you,