Comments: ESP32-C3 Super Mini

[utterances-bot]

ESP32-C3 Super Mini - DONE.LAND

Compact And Affordable Microcontroller Board With Great Functionality

https://done.land/components/microcontroller/families/esp/esp32/developmentboards/esp32-c3/c3supermini/

[aardwolf2]

I too ended up with bad super minis. Thanks to your article I tried lowering the TXpower which worked most of the time, however as suggested sticking my finger on the antenna worked even better, I guessed it was down to the extra capacitive loading, So i set the two GPIO pins, 20 and 21 which probably have tracks routed under the oscillator, to ground. Which appears to have worked even on full 20dB. Yes you lose 2 GPIO, but it works.

[TobiasPSP]

Thanks so much for sharing your solution!

That’s exactly why I do all this effort with done.land: to have a platform for all of us to collect crucial info about these components.

I‘ll try the gpio trick (I have plenty of these affected boards) and then update the article.

While it is sad to lose 2 gpios, for most of my use cases that’s still ok, and as a simple „software“ solution, it is quite elegant. Thanks again!

[flute2k3]

when you say "Bypasses the voltage regulator and does not turn on the red power LED. Use this pin for low-energy scenarios, such as battery operation", it is actually not... the voltage applied on 3.3V pin will back feed the power LED via the mosfet body diode inside ME6211, draw something like additional 0.2mA current.

[TobiasPSP]

Thank you for your feedback. There may be different pcb layouts. I‘ll check with the latest batch and update the article. Again, thank you for calling this out.

[AndrewLinden]

@TobiasPSP many thanks about this amazing information compendium!

In the section about I2C you write about hardware I2C pins and when not using these using software i2C. I think this is not correct. The ESP-C3 has GPIO matrix and peripherial signals such as I2C can be routed to any GPIO pins. Espressif documentation about it is here:
https://documentation.espressif.com/esp32-c3_technical_reference_manual_en.pdf#iomuxgpio

[TobiasPSP]

Andrew, you are absolutely correct: All pins route I2C through the GPIO matrix—no direct IO_MUX path exists for I2C signals on ESP32-C3, unlike classic ESP32 where defaults like GPIO21/22 can bypass it for lower latency.

So there are no „hardware optimized“ gpios here, just Arduino framework defaults.

Arduino default gpios for i2c may have shorter PCB traces, stronger internal drive strength configs, or less electrical noise/interference in your setup, yielding crisper SCL edges and reliable higher freq. but this is speculation. So yes, you can probsbly use any gpio on the c3 without penalty.

Thanks for pointing this out!