107 lines
4.1 KiB
C
107 lines
4.1 KiB
C
/*
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* MIT License
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*
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* Copyright (c) 2018 Nis Wechselberg
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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/**
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* Firmware for MiCS-6841-based I2C adapter board.
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* Implements a behaviour compatible to the Seeedstudio
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* Grove Mutichannel Gas Sensor-library.
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*
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* Using ATmega core from:
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* https://raw.githubusercontent.com/carlosefr/atmega/master/package_carlosefr_atmega_index.json
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*
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* Pin mapping:
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* Heater Enable (out): PB0 / Digital 8 (Active low)
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* NH3 resistance (in): PC0 / Analog 0
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* RED resistance (in): PC1 / Analog 1
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* OX resistance (in): PC2 / Analog 2
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*
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* SDA: PC4 / Analog 4
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* SCL: PC5 / Analog 5
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*/
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#ifndef MiCS6814_V1_H
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#define MiCS6814_V1_H
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// Include Wire library for I2C support
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#include <Wire.h>
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#include <EEPROM.h>
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// Pin mapping constants
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#define HEATER 8
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#define NH3_IN A0
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#define RED_IN A1
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#define OX_IN A2
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/*
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* I2C commands
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*
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* Taken from Grove Mutichannel Gas Sensor Library, just some renaming done here
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*/
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#define CMD_GET_NH3 1 // Retrieve current resistance for NH3 sensor channel
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#define CMD_GET_RED 2 // Retrieve current resistance for RED sensor channel
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#define CMD_GET_OX 3 // Retrieve current resistance for OX sensor channel
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#define CMD_GET_ALL 4 // Retrieve all sensor resistance channels
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#define CMD_CHANGE_I2C 5 // Change I2C address of the sensor
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#define CMD_READ_EEPROM 6 // Read stored uint16_t data from EEPROM (MSB is transmitted first)
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#define CMD_SET_R0 7 // Set custom R0 values
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#define CMD_GET_R0 8 // Retrieve current R0 values
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#define CMD_GET_R0_DEFAULT 9 // Retrieve default R0 values
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#define CMD_CONTROL_LED 10 // Control status LED (no LED on my board, but Grove supports is, so ... meh!)
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#define CMD_CONTROL_PWR 11 // Heater control
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/* EEPROM Addresses
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*
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* These match the addresses used in the Grove library
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* If the library was implemented in a sensible fashion I would
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* be free to use my own mapping here.
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* However, the library accesses eeprom data directly quite frequently, so ... meh!
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*/
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#define EEPROM_VERSION_ID 0 // Identifier for the current version, Grove uses value 1126 to identify version 2 of their sensor.
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#define EEPROM_R0_DEFAULT_NH3 2
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#define EEPROM_R0_DEFAULT_RED 4
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#define EEPROM_R0_DEFAULT_OX 6
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#define EEPROM_R0_NH3 8
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#define EEPROM_R0_RED 10
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#define EEPROM_R0_OX 12
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#define EEPROM_I2C_ADDR 20
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#define DATA_VERSION_ID 1126
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#define DATA_I2C_ADDR 0x04
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#define DATA_R0_DEFAULT_NH3 123
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#define DATA_R0_DEFAULT_RED 123
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#define DATA_R0_DEFAULT_OX 123
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// Runtime data
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uint32_t timer; // Timer value of last update
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uint16_t resistanceNH3; // Current resistance value for NH3 channel
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uint16_t resistanceRED; // Current resistance value for RED channel
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uint16_t resistanceOX; // Current resistance value for OX channel
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uint8_t i2CResp[6]; // Buffer for I2C response
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uint8_t i2CRespLength; // Amount of bytes to be sent to master
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#endif
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