ESP32-C3 Dev Kit In-Circuit Debugging

Adding In-Circuit debugging to the ESP32-C3 Dev Kit.

Using an old USB cable/breakout I had lying around. You’ll probably want to use USB-C. 😉

Attach nothing to the Dev Kit USB connector.

Also, I use a lot of power and grounds.


Debugging (at a break point) in VSCode on Ubuntu.


> The ESP32-C3 is said to be the successor to the ESP-8266. And like the 8266 is limited in Programmable IO compared with the ESP-32. This USB method of In-Circuit debugging uses two processor PIO pins instead of the four pins needed for JTAG debugging–freeing up two pins for general use.

> In the processor’s low power modes, the USB interface is powered down and USB debugging is not possible. If you need to debug while in one of the two low power modes, you should use the JTAG interface.

> Visual Studio Code operates at the source code level and is able to use this method of debugging to set breakpoints, examine variables and the stack, single-step high level source code and flash the device. But VSCode has no knowledge of the processor details (e.g. CPU internal registers, memory configuration–access and format). As a result single-stepping through assembly code while examining CPU registers, flags and memory is not possible.
But the detailed knowledge gained while single-stepping assembly code would be an advantage in learning the ESP32-C3’s risc-v architecture. VSCode teamed with PlatformIO could provide this capability and I have filed an issue to that purpose on PlatformIO’s github.

APRS Client on a MCU

I wanted to develop an APRS client on an MCU (ESP-32) instead of a SBC (Raspberry Pi).

This client would use a modem/radio combination (Mobilinkd TNC3/Baofeng UV-5R) to get on the air (144.390 MHz). The client connects to the TNC3 over a Bluetooth Low Energy (BLE) link and is secure against Man-In-The-Middle attacks,

Looking around, I settled on hardware similar to that Amazon’s AWS IoT EduKit workshop uses but using APRS instead of the internet—of course.

I choose the (relatively) inexpensive M5Stack Core2 unit ( 
Or I might ultimately build my own using an ESP32 development board.

The video demonstrates the first step in using APRS–position beaconing and registering with a station having an APRS-IS (internet) connection. After the first beacon, you must transmit a beacon every 30 minutes to stay current in the system.

Step 1 for APRS, beacon your position and register with APRS-IS.
Step 2 to follow…

Video Notes:
Next time use a script
It’s APRS-IS not -SI
Be cool. Don’t sound so excited when it works!

DSP Done Dirt Cheap

Created a new GitHub and added a Real-Time FIR filter implementation from Espressif’s DSP Library.

Time permitting, I’ll be adding new DSP Library functions and documenting them here and on my YouTube channel @wm6h.

Using the Arduino IDE allows me to add Arduino Libraries for servos, LEDs, etc. along with action figure leitmotifs (WAV audio) for my Holiday displays.