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ams5812

This library communicates with AMS-5812 pressure transducers.

Description

The Analog Microelectronics AMS-5812 pressure transducers are fully signal conditioned, amplified, and temperature compensated over a temperature range of -25 to +85 C. These sensors generate data with high precision, high stability and low drift. Digital measurements are sampled with a 14 bit resolution. The AMS 5812 sensors are available in a wide variety of pressure ranges and in configurations suited for barometric, differential, and bidirectional differential measurement.

Usage

This library communicates with the AMS-5812 sensors using an I2C interface. The default I2C address for the AMS-5812 is 0x78; however, a USB starter kit may be purchased to enable programming additional slave addresses. Pressure and temperature data can be provided at rates of up to 2 kHz.

Installation

CMake is used to build this library, which is exported as a library target called ams5812. The header is added as:

#include "ams5812/ams5812.h"

The library can be also be compiled stand-alone using the CMake idiom of creating a build directory and then, from within that directory issuing:

cmake .. -DMCU=MK66FX1M0
make

This will build the library and an example executable called ams5812_example. The example executable source files are located at examples/ams5812_example.cc. Notice that the cmake command includes a define specifying the microcontroller the code is being compiled for. This is required to correctly configure the code, CPU frequency, and compile/linker options. The available MCUs are:

  • MK20DX128
  • MK20DX256
  • MK64FX512
  • MK66FX1M0
  • MKL26Z64
  • IMXRT1062_T40
  • IMXRT1062_T41

These are known to work with the same packages used in Teensy products. Also switching packages is known to work well, as long as it's only a package change.

The ams5812_example targets creates an executable for communicating with the sensor using I2C communication. The example target also has a _hex for creating the hex file to upload to the microcontroller.

Namespace

This library is within the namespace bfs.

Methods

Ams5812(i2c_t3 *bus, uint8_t addr, Transducer type) Creates an Ams5812 object. A pointer to the I2C bus object is passed along with the I2C address of the sensor and the AMS-5812 transducer type. The enumerated transducer types are:

Sensor Name Enumerated Type Pressure Type Pressure Range
AMS 5812-0000-D AMS5812_0000_D differential / relative 0...517 Pa
AMS 5812-0001-D AMS5812_0001_D differential / relative 0...1034 Pa
AMS 5812-0000-D-B AMS5812_0000_D_B bidirectional differential -517...+517 Pa
AMS 5812-0001-D-B AMS5812_0001_D_B bidirectional differential -1034...+1034 Pa
AMS 5812-0003-D AMS5812_0003_D differential / relative 0...2068 Pa
AMS 5812-0008-D AMS5812_0008_D differential / relative 0...5516 Pa
AMS 5812-0015-D AMS5812_0015_D differential / relative 0...10342 Pa
AMS 5812-0003-D-B AMS5812_0003_D_B bidirectional differential -2068...+2068 Pa
AMS 5812-0008-D-B AMS5812_0008_D_B bidirectional differential -5516...+5516 Pa
AMS 5812-0015-D-B AMS5812_0015_D_B bidirectional differential -10342...+10342 Pa
AMS 5812-0030-D AMS5812_0030_D differential / relative 0...20684 Pa
AMS 5812-0050-D AMS5812_0050_D differential / relative 0...34474 Pa
AMS 5812-0150-D AMS5812_0150_D differential / relative 0...103421 Pa
AMS 5812-0300-D AMS5812_0300_D differential / relative 0...206843 Pa
AMS 5812-0600-D AMS5812_0600_D differential / relative 0...413685 Pa
AMS 5812-1000-D AMS5812_1000_D differential / relative 0...689476 Pa
AMS 5812-0030-D-B AMS5812_0030_D_B bidirectional differential -20684...+20684 Pa
AMS 5812-0050-D-B AMS5812_0050_D_B bidirectional differential -34474...+34474 Pa
AMS 5812-0150-D-B AMS5812_0150_D_B bidirectional differential -103421...+103421 Pa
AMS 5812-0150-B AMS5812_0150_B barometric 75842...120658 Pa
AMS 5812-0150-A AMS5812_0150_A absolute 0...103421 Pa
AMS 5812-0300-A AMS5812_0300_A absolute 0...206843 Pa

For example, the following code declares an AMS5812 object called ams with an AMS5812-0008-D sensor located on I2C bus 0 with an I2C address of 0x10:

bfs::Ams5812 ams(&Wire, 0x10, bfs::Ams5812::AMS5812_0008_D);

bool Begin() Initializes communication with the sensor and configures the sensor driver for the specified transducer. True is returned if communication is able to be established with the sensor and configuration completes successfully, otherwise, false is returned.

bool status = ams.Begin();
if (!status) {
  // ERROR
}

bool Read() Reads data from the AMS-5812 and stores the data in the Ams5812 object. Returns true if data is successfully read, otherwise, returns false.

/* Read the sensor data */
if (ams.Read()) {
}

float pressure_pa() Returns the pressure data from the Ams5812 object in units of Pa.

float pressure = ams.pressure_pa();

float die_temperature_c Returns the die temperature of the sensor from the Ams5812 object in units of degrees C.

float temperature = ams.die_temperature_c();

About

AMS 5812 sensor driver.

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