Arduino MCP980X Temperature Sensor Library v1.0

https://github.com/JChristensen/MCP980X ReadMe file
Jack Christensen Mar 2014

Introduction

Arduino Library for Microchip MCP9800/1/2/3 2-Wire High-Accuracy Temperature Sensors

A lightweight implementation that exposes all functionality of the Microchip MCP980X sensors. Temperatures are dealt with in the integer domain to avoid the code size and runtime overhead associated with floating-point. Still, it is easy enough to perform the necessary conversions should the user wish to work in floating-point format.

Temperatures read from the device's registers are returned as °C*16. (If the device resolution is set to less than 12 bits, the corresponding lower order bits are simply returned as zero.) Temperatures can alternately be read as °F*10.

When writing the Hysteresis and Limit-Set registers, the value must be given as °C*2, which corresponds to the internal representation in these registers.

Bit masks for the control register are provided in the MCP980X.h file.

"Arduino Library for Microchip MCP9800/1/2/3" by Jack Christensen is licensed under CC BY-SA 4.0.

Installation

To use the MCP980X library:

Go to https://github.com/JChristensen/MCP980X, click the Download ZIP button and save the ZIP file to a convenient location on your PC.
Uncompress the downloaded file. This will result in a folder containing all the files for the library, that has a name that includes the branch name, usually MCP980X-master.
Rename the folder to just MCP980X.
Copy the renamed folder to the Arduino sketchbook\libraries folder.

Examples

The following example sketch is included with the MCP980X library:

MCP980X_EX1: Demonstrates basic reading of ambient temperature in Celsius and Fahrenheit, conversion to floating-point, changing device options via the Cofiguration register, and changing the Limit-Set and Hysteresis registers.

Usage notes

The MCP980X library is designed for use with Arduino version 1.0 or later.

To use the MCP980X library, the standard Arduino Wire library must also be included. For brevity, this include is not repeated in the examples below:

#include <Wire.h>         //http://arduino.cc/en/Reference/Wire (included with Arduino IDE)

Enumeration

###MCP980X_REGS_t #####Description Symbolic names for the MCP980X registers. #####Values

AMBIENT -- for the Ambient Temperature Register
HYSTERESIS -- for the Temperature Hysteresis Register
LIMITSET -- for the Temperature Limit-Set Register

Constructor

###MCP980X(int LS_ADDR_BITS) #####Description Instantiates an MCP980X sensor object. #####Syntax MCP980X mySensor(0); #####Parameters LS_ADDR_BITS: An integer (int) representing the least-significant three bits of the I2C device address (i.e. a value between 0 and 7). Note that some devices in the MCP980X family allow the user to select the least significant three bits of the address, and some have a fixed address from the factory. See the datasheet for details. As ever, all devices on an I2C bus must have unique addresses.

Methods

###begin(void) #####Description Initializes the library. Call this method once in the setup code. #####Syntax mySensor.begin(void); #####Parameters None. #####Returns None. #####Example

MCP980X mySensor(0);
mySensor.begin();

###readTempC16(MCP980X_REGS_t reg) #####Description Reads one of the three temperature registers from the sensor. #####Syntax mySensor.readTempC16(MCP980X_REGS_t reg); #####Parameters reg: The temperature register to read, AMBIENT, HYSTERESIS or LIMITSET (MCP980X_REGS_t) #####Returns Temperature as degrees Celsius times 16 (int). #####Example

MCP980X mySensor(0);
mySensor.begin();
int c16 = mySensor.readTempC16(AMBIENT);
float C = c16 / 16.0;

###readTempF10(MCP980X_REGS_t reg) #####Description Reads one of the three temperature registers from the sensor. #####Syntax mySensor.readTempF10(MCP980X_REGS_t reg); #####Parameters reg: The temperature register to read, AMBIENT, HYSTERESIS or LIMITSET (MCP980X_REGS_t) #####Returns Temperature as degrees Fahrenheit times 10 (int). #####Example

MCP980X mySensor(0);
mySensor.begin();
int f10 = mySensor.readTempF10(AMBIENT);
float F = f10 / 10.0;

###writeTempC2(MCP980X_REGS_t reg, int value) #####Description Sets the Temperature Hysteresis Register or the Temperature Limit-Set Register. #####Syntax mySensor.writeTempC2(MCP980X_REGS_t reg, int value); #####Parameters reg: The temperature register to write, HYSTERESIS or LIMITSET (MCP980X_REGS_t). If given the AMBIENT temperature register, no action is taken (AMBIENT is a read-only register).
value: The temperature value to set, in degrees Celsius times two (int) #####Returns None. #####Example

MCP980X mySensor(0);
mySensor.begin();
mySensor.writeTempC2(HYSTERESIS, 25 * 2);	//set hysteresis register to 25°C
mySensor.writeTempC2(LIMITSET, 100 * 2);	//set limit-set register to 100°C

###readConfig(void) #####Description Reads the value of the configuration register. #####Syntax mySensor.readConfig(void); #####Parameters None. #####Returns Configuration register value (byte) #####Example

MCP980X mySensor(0);
mySensor.begin();
byte config = mySensor.readConfig();

###writeConfig(uint8_t value) #####Description Writes a value to the configuration register. #####Syntax mySensor.writeConfig(byte value); #####Parameters value: The value to be written to the register. See the MCP980X.h file for symbolic definitions for the bits in the configuration register. #####Returns None. #####Example

MCP980X mySensor(0);
mySensor.begin();
//set ADC resolution to 12 bits and the fault queue length to 6
byte config = ADC_RES_12BITS | FAULT_QUEUE_6;
mySensor.writeConfig(config);

PaxInstruments/MCP980X