Custom ESP32-C3 not detecting COM port (crystal problem?)

[ESP_Sprite]

No, not really... the series component indicated by the hardware design guideline is a zero-ohm resistor, possibly as a placeholder if you need something there, but I haven't seen a situation where it actually is needed.

One thing you may try is to feed an external 40MHz signal into XTAL_P. If that suddenly makes everything work, the issue is likely to be something related to the crystal. If the ESP32C3 still doesn't work, it may be an issue with that, e.g. bad soldering, or the CHIP_EN pin at the wrong level.

[ESP_LJH]

If pin 22,23,24 are used? These pins could not be used.
As for the strange crystal figure, do you have our module on your hand? Could you try to solder your crystal on our module? Or solder our crystal on your PCB? You could also swap ESP32-C3 chip and try.
And how is your PCB layout around crystal, maybe if the layout is not good so crystal will be affected.

[ollieelliot]

If pin 22,23,24 are used? These pins could not be used.
As for the strange crystal figure, do you have our module on your hand? Could you try to solder your crystal on our module? Or solder our crystal on your PCB? You could also swap ESP32-C3 chip and try.
And how is your PCB layout around crystal, maybe if the layout is not good so crystal will be affected.

As for now, the section using pin 22,23,24 are not soldered. What module do you mean? I have the Esp32 C3 mini devkit, however that uses the finished module so there is no external crystal what I can see on the devkit. I have already tested swapping the C3 chip and crystal. Say that I order a new PCB, are there any changes I should do to maybe increase the chances of it working?

[ollieelliot]

No, not really... the series component indicated by the hardware design guideline is a zero-ohm resistor, possibly as a placeholder if you need something there, but I haven't seen a situation where it actually is needed.

One thing you may try is to feed an external 40MHz signal into XTAL_P. If that suddenly makes everything work, the issue is likely to be something related to the crystal. If the ESP32C3 still doesn't work, it may be an issue with that, e.g. bad soldering, or the CHIP_EN pin at the wrong level.

Unfortunately I don't have access to a function generator that can produce 40Mhz, the highest I have available goes to 10Mhz. As for the CHIP_EN, bootstrap pins and all the power/decoupling I have verified that all the levels are correct. The CHIP_EN has 3.3V from the pull-up.

[ESP_LJH]

I mean open the shield box and use crystal we use in your board, I just want to figure it out why the crystal wave is so strange, so I want to make sure if your crystal is soldered on our module, the wave is still the same. BTW, which pin of crystal do you measure, XTAL_P or XTAL_N? Could you measure both pins?

[ollieelliot]

Hello again,

After taking some time off from this project I came back to it and realized I never soldered the ground pad underneath the ESP32-C3 chip, stupid mistake. I must've simply had a enormous brain fart when soldering.

Everything works as expected now.

Sorry for this.