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USB CDC on Boot Settings

Take note of the option labeled "USB CDC on Boot" when selecting the Board from the Tools menu. This option sets the serial outputs and defines their label for use in code. The SparkFun variants default to Enable USB CDC on boot which sets both Serial and Serial0 as available serial ports. In this configuration, Serial corresponds to the direct USB/Serial converter on the chip (and the USB-C interface) and Serial0 corresponds to the UART0 bus (default pins are 16 and 17).

With either setting, Serial1 is available and refers to the UART1 bus (default pins are 4 and 5).


The board definition for the Thing Plus - ESP32-C6 sets IO23 to use espressif's RGB_BUILTIN code support. This automatically includes the necessary code to control an RGB LED easily when calling RGB_BUILTIN. Unfortunately, this means the RGB PTH pin (IO23) can run into code conflicts when users attempt to use it for another purpose. If you really need IO23 for something other than the RGB LED, you may need to modify the board definition files in the ESP32 Arduino boards package. Modifying these files is beyond the scope of this tutorial and is not supported by SparkFun.

General Troubleshooting

Need Help?

If you need technical assistance or more information on a product that is not working as you expected, we recommend heading on over to the SparkFun Technical Assistance page for some initial troubleshooting.

SparkFun Technical Assistance Page

If you can't find what you need there, the SparkFun Forums is a great place to search product forums and ask questions.

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