ESP32 Forum

Hello,

I am made a project with ESP32-C3-MINI-1-H4 module in the past and it works great. I could program it directly from USB out of the box. But for a newer project I used ESP32-C3-MINI-1-N4 variant. As per the datasheet,

The ESP32-C3FN4 chip and the ESP32-C3FH4 chip vary only in the ambient temperature

. However after making the PCB I can't program it directly from USB.
So I pull the GPIO 9 LOW to put it into boot mode and when I compare it with the previous board that I have I found, in the serial monitor my previous board (based on ESP32-C3FH4 chip) shows while this new board (based on ESP32-C3FN4 chip) shows I don't understand why it functions differently on both modules while rest of the circuit is identical on both boards.
How can I change this boot mode to make the ESP32-C3-MINI-1-N4 module program over USB since I didn't break out the UART pins.
Please help!
Thanks

Can you check GPIO8? It should have a high level (either externally or due to the internal pullup)

Yes, GPIO 8 has external 10k pullup resistor on both boards

Can you check if it's actually doing its job of pulling the GPIO up? There've been some instances with people with issues like you have that had a short to ground under the module.

Okay, there are external circuitry connected on the GPIO 8 and I think that might pulling the pin low, I removed it and now I am able to program it via USB, thank you so much for your help.

You are welcome!