File T67XX.h

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This is a library for the Telaire T67XX series miniature CO2 sensor module.More...

#include <Arduino.h>
#include <Wire.h>

Classes

Type	Name
class	T67XX Class for T67XX CO2 sensor communication.

Public Types

Type	Name
enum	Modbus_FC Modbus function codes.
union	StatusRegister Each bit represents the status of a device function or error.
enum	T67XX_Registers T67XX register addresses.

Macros

Type	Name
define	T67XX_DEFAULT_I2C_ADDR `0x15` Default I2C address.
define	T67XX_MEASURE_DELAY `2250` Delay between starting PPM measurement and reading the data (manufacturer recommended value).
define	T67XX_READ_DELAY `10` Delay between read/write transmissions (manufacturer recommended value).
define	T67XX_REG_VAL_DISABLE `0x0000` Value to disable a register.
define	T67XX_REG_VAL_ENABLE `0xFF00` Value to enable a register.

Detailed Description

These sensors use UART and I2C to communicate. This library is designed for the I2C communication option. 2 pins are required for the interface. To enable I2C communication, connect pin CTRL (pin 6 of the module) to GND.

Author:

[ALD-DSL/ATARI_RESEARCH_LAB]

Date:

[2024-07-22/2025-10-15]

Version:

2.0

Copyright:

GNU General Public License version 3 or later

Note:

This module is based on the library by Yaroslav Osadchyy (drug123@gmail.com) with MIT License

MIT license, all text above must be included in any redistribution

Public Types Documentation

enum Modbus_FC

Modbus function codes.

enum Modbus_FC {
    MODBUS_READ_COIL = 0x01,
    MODBUS_READ_DISCRETE_INPUT = 0x02,
    MODBUS_READ_MULTIPLE_HOLDING_REGISTERS = 0x03,
    MODBUS_READ_INPUT_REGISTERS = 0x04,
    MODBUS_WRITE_SINGLE_COIL = 0x05,
    MODBUS_WRITE_SINGLE_REGISTER = 0x06,
    MODBUS_WRITE_MULTIPLE_COILS = 0x0F,
    MODBUS_WRITE_MULTIPLE_REGISTERS = 0x10
};

The I2C implementation uses the Modbus protocol and encapsulates the message in I2C format; however, in this case CRC is not included. Function codes vary according to the data type and whether a single or multiple read/write is performed.

Modbus data model:

Discrete Inputs: 1bit. Read only.
Coils: 1bit. Read/Write.
Input Registers: 16bits. Read only.
Holding Registers: 16bits. Read/Write.

union StatusRegister

Each bit represents the status of a device function or error.

Allows verification of device status and the different errors that can occur.

Under error conditions, a "1" indicates an error; a "0" indicates no error. A Flash error is fatal (i.e., no recovery). Calibration errors can be cleared by running the calibration procedure again with correct results.

Under calibration conditions, a "1" indicates that the calibration cycle is in progress. No other calibration cycle can be started while one is in progress and the Modbus response will report an error to the new calibration request.

If the warmup bit (WARMUP) is active, the sensor is in a mode where internal registers and gas data (ppm) are being initialized and are not necessarily correct.

enum T67XX_Registers

T67XX register addresses.

enum T67XX_Registers {
    T67XX_REG_FIRMWARE = 0x1389,
    T67XX_REG_STATUS = 0x138A,
    T67XX_REG_PPM = 0x138B,
    T67XX_REG_RESET = 0x03E8,
    T67XX_REG_SPCAL = 0x03EC,
    T67XX_REG_FLASH_UPDATE = 0x03ED,
    T67XX_REG_ADDRESS = 0x0FA5,
    T67XX_REG_ABC_LOGIC = 0x03EE,
    T67XX_REG_MOD_MODE = 0x100B
};

Macro Definition Documentation

define T67XX_DEFAULT_I2C_ADDR

Default I2C address.

#define T67XX_DEFAULT_I2C_ADDR `0x15`

define T67XX_MEASURE_DELAY

Delay between starting PPM measurement and reading the data (manufacturer recommended value).

#define T67XX_MEASURE_DELAY `2250`

define T67XX_READ_DELAY

Delay between read/write transmissions (manufacturer recommended value).

#define T67XX_READ_DELAY `10`

define T67XX_REG_VAL_DISABLE

Value to disable a register.

#define T67XX_REG_VAL_DISABLE `0x0000`

define T67XX_REG_VAL_ENABLE

Value to enable a register.

#define T67XX_REG_VAL_ENABLE `0xFF00`

The documentation for this class was generated from the following file firmware/T67XX.h