ESP32 TWI Relay

The program is designed to run on a Seeed XIAO ESP32C3 to relay events published to an AMQP topic to a TWI bus as well as reads the state of devices on the bus and relays them back.

This uses the AduinoJson and EspMQTTClient libraries.

Configuration

JSON file, written to the SPIFFS, needs to define the following:

{
  "auth": {
    "username": "username",
    "password": "password"
  },
  "server": {
    "ipAddress": "192.168.1.2",
    "port": 5672
  },
  "readDevices": [
    {
      "address": 80, // Corresponding to device: 0x50
      "length": 2
    },
    {
      "address": 81, // Corresponding to device: 0x51
      "length": 3
    }
  ],
  "readInterval": 1, // seconds
  "topicPrefix": "i2c-agent",
  "wifi": {
    "ssid": "Some-WIFI-SSID",
    "password": "wifi-password"
  }
}

TWI Relay

If the topicPrefix has been set to i2c-agent the micro-controller will subscribe to the topics with a pattern: i2c-agent/output/#. To write to a device with address 0x50 the topic: i2c-agent/output/50 should be published to with a JSON array of the bytes to write to the device.

For the example config above the micro-controller with read 2 bytes from 0x50 and 3 bytes from 0x51 and publish the byte arrays as JSON array of numbers to the topics: i2c-agent/input/50 and i2c-agent/input/51 respectively.