It appears you answered your question. :)

As documented, just make sure your custom commands fall under the CmdOurCustomCmds (or EZB Command 0 (zero))

} else if (cmd == CmdOurCustomCmds) {

    byte cmd2 = ReadByte();

  if (cmd2 == CmdCustomSomething1) {

    // do something for your custom thing

  } else if (cmd2 == CmdCustomSomething2) {

    // do something for your custom thing

  } else if (cmd2 == CmdCustomSomething2) {

    // do something for your custom thing

  } else if (cmd2 == CmdCustomSomething3) {

   // do something for something else

To add new functions to the EZB firmware for the Arduino Due/Mega, you can indeed use the CmdOurCustomCmds (Command 0) as a starting point for creating custom commands. This is a designated area in the firmware for user-defined commands, which helps avoid conflicts with existing or future ARC commands.

Here's a step-by-step guide on how to define new custom command functions in the Arduino Mega EZB firmware:

1. Identify the Custom Command Range:

   • Ensure that the custom command numbers you choose do not conflict with existing commands in the firmware. It's a good practice to define a range of numbers for your custom commands that are unique to your project.

2. Modify the Firmware:

   • Open the Arduino Mega EZB firmware source code in the Arduino IDE or your preferred development environment.
   • Locate the section of the code that handles the CmdOurCustomCmds command.
   • Define your custom command numbers as constants or enums for better code readability. For example:

     const byte CmdCustomAction1 = 1;
     const byte CmdCustomAction2 = 2;
     // ... and so on
     

   • Add additional else if statements within the CmdOurCustomCmds block to handle your new custom commands. For example:

     } else if (cmd == CmdOurCustomCmds) {
       byte cmd2 = ReadByte();
       if (cmd2 == CmdCustomAction1) {
         // Handle custom action 1
       } else if (cmd2 == CmdCustomAction2) {
         // Handle custom action 2
       }
       // ... additional custom commands
     }
     

   • Implement the functions that correspond to each custom command. These functions will contain the logic for the actions you want to perform when the command is received.

3. Compile and Upload the Firmware:

   • Once you have added your custom commands and their corresponding functions, compile the firmware.
   • Upload the compiled firmware to your Arduino Mega.

4. Update Your ARC Skill:

   • In your ARC skill, update the code to send the custom commands to the Arduino Mega. Use the CmdOurCustomCmds command followed by the specific custom command number you defined.
   • For example, to send CmdCustomAction1, you would send a packet with CmdOurCustomCmds followed by CmdCustomAction1.

5. Testing:

   • Test your ARC skill to ensure that the custom commands are being sent correctly and that the Arduino Mega is responding as expected.

Regarding the number range for custom commands, there isn't a specific range reserved for user-defined commands. However, it's essential to choose numbers that are not already in use by the firmware and are unlikely to be used in future updates. Using sub-commands under CmdOurCustomCmds is a good approach, as it organizes your custom commands under a single parent command and reduces the likelihood of conflicts.

Remember to document your custom commands and maintain a list of them to ensure that you don't accidentally reuse numbers for different functions in the future.

A good example would be to look at DJ's Balance Robot firmware for the Arduino Mega, which is what you are using. The changes will be similar; here is the link: synthiam.com/Support/Hardware/Balance-Robot

Thanks for confirming this for me.

This is long but you can skip through it ... It's a live hack where i demonstrated extending the ezb protocol for the wheel encoder.