ESP32C3-mini-1 problem with strapping pins

[svenssonjoel]

Hello,

We are using a lot of ESP32C3-mini-1 modules. We used to have modules with Package Code XXN4 but on our latest purchases we have Package Code M4N4. We are noticing that these two batches of mini-1 modules behave differently on boot-up.

We are using USB to connect and flash (Not uart).

We are unable to flash the M4N4 modules unless there is 0V on GPIO2 and GPIO3. If the module is started up with other combinations of
3V and 0V on GPIO 2 and 3 the esptool errors out: "[Errno 71] Protocol error"

(esptool version 4.5.1)

With 0V on GPI0 2 and 3 esptool reports:
"
esptool.py v4.5.1
Serial port /dev/ttyACM0
Connecting...
Detecting chip type... ESP32-C3
Chip is ESP32-C3 (revision v0.4)
Features: WiFi, BLE
Crystal is 40MHz
MAC: XXXXXXXXXXX
Uploading stub...
Running stub...
Stub running...
Warning: ESP32-C3 has no Chip ID. Reading MAC instead.
MAC: XXXXXXXXXXXX
Hard resetting via RTS pin..
"

This behavior is clearly different between revision v0.3 and revision v0.4 of of the esp32c3 chips we have in our modules (XXN4 v0.3, M4N4 v0.4).

Thank you and best regards

[hristesp]

I have had the same issue however have not been able to pull GPIO2 down. I have had our devices with modules marked XXN4 function fine, however when attempting to flash new devices (exact same PCB design) with modules marked M4N4, I get the error "Errno 32: Broken Pipe". We are also using USB to connect, not UART nor JTAG, and cannot even monitor the device.

We removed the front cover of the module and found the date code that showed the new modules (marked M4N4) were manufactured in 2023, while the functioning modules marked "XXN4" were manufactured in 2021.

Were you able to get your modules working? Does USB connectivity not work with modules manufactured in 2023?

[jonnny]

Hello,

We recently received a new batch of PCBs assembled with M4N4 parts, and we've encountered an issue similar to one you experienced previously: the USB connection behavior has changed, making it impossible to flash the boards. Specifically, the strapping pin GPIO9 is set high while GPIO8 is low. Notably, our previous batch used ESP32C3 chips with the identifier XXN4 and worked flawlessly. Did you manage to resolve the problem you had before?

Looking forward to your advice. Thank you!

Best regards,
Jonny

[AndreRamakers]

Hi all,

Same for me. I can't flash modules with M4N4 while the others work just fine. I have sent a message to Espressif and hope that they come up with a solution.

André

[aschewski]

Is there any new information or a solution by now?
I am planning to produce some PCBs including assembly with JLCPCB, so it would be best to avoid any surprises. Do I have a way of finding out which revision the chip is? Mine is the ESP32-C3-MINI-1-N4 (C2838502 / LCSC). Can I assume that it's version v0.4? According to the datasheet, that seems to be the case.

Are there any other designations? I’m seeing mentions of XXN4 / M4N4.

I would like to flash and use the Serial Monitor via the built-in USB serial/JTAG module (IO18/IO19). Do I need to pay attention to the strapping pins? The datasheet doesn’t seem to directly address this. In many reference schematics, the strapping pins are not considered. It's all a bit confusing! Could someone please help me?