Not able to program ESP32-C3-MINI-1-N4 on a custom PCB board

[shivdeepak]

Hello,

I am trying to program ESP32-C3-MINI-1-N4 using a CP2102N based programmer, and I have failed to program even after using up 7 different modules, and tried quite a lot of things.
- I have used a stencil to put solder paste and used a reflow oven to solder it
- I have also tried hot air gun to solder the module on the PCB


At this point, I am very confident that I have soldered the chip correctly on to the board, and I am also using the reference schematic from the devkitM board for the custom PCB.

My programmer is not able to recognize the ESP32-C3-MINI-N4 module, but when I wire 3V3, GND, GPIO9, EN, RX, TX on DevKitM, it is able to recognize the chip. I have also tried directly soldering the ESP32-C3-MINI-N4 module to the wires of the programmer without a PCB. No luck.


At this point, I feel like I have no other options I can trying out right now, and I want to reach out to the community to see if anybody was able to get the ESP32-C3-Mini-1-N4 working on a custom PCB, and soldering process they used, and has any idea what I am doing wrong. Happy to share schematics and board layout.

Thanks.

[ESP_Sprite]

This

I have also tried directly soldering the ESP32-C3-MINI-N4 module to the wires of the programmer without a PCB. No luck.

leads me to think you may have mis-interpreted something in how to hook up that module, as in, it may not be your soldering process at fault. Can you share your PCB / schematic here?

If you can't, some easy things to check:
- If you power on the module, do you get a bootup message on the Tx pin of the module? (Use a scope/LA to look for this.)
- Does that message make it to the USB-serial module and can you see it on the PC? If so, can you post the contents?
- If you pull GPIO9 low while powering up, does the bootup message reflect that you're in download mode?
- If it does, can you trace the Tx from the USB-serial to the module, see if that's OK?

[shivdeepak]

leads me to think you may have mis-interpreted something in how to hook up that module, as in, it may not be your soldering process at fault. Can you share your PCB / schematic here?

I have attached the schematic of the programmer and the esp32-c3-module on the custom PCB

- If you power on the module, do you get a bootup message on the Tx pin of the module? (Use a scope/LA to look for this.)

I am going to try this now. Will even a blank ESP32-C3 module show message on the TX pin?

- Does that message make it to the USB-serial module and can you see it on the PC? If so, can you post the contents?

I don't think so, as esp-idf.py build fails with "Time out waiting for packet header". Pretty much like nothing is connected to it. Is it possible if there is a baud rate or some other config mismatch?

- If you pull GPIO9 low while powering up, does the bootup message reflect that you're in download mode?

I will try this now.

- If it does, can you trace the Tx from the USB-serial to the module, see if that's OK?

I will try this now.


Thanks for helping with this.

[xien551]

hey, shivdeepak, I think Sprit have given you many reliable suggestion, you can follow this.

And I would like to give you some advises else. I have direct hundreds of students to solder a PCB. The schematic is very simple, but some of them cannot make the board work even using a week. One of the most happen mistake is dry joint, which means the joint looks good, and you check it with multi-meter, it is OK. However, it is not reliable, when you power the board, they are disconnected. If you check them again, they are still good. Very confusing.

For your board, the most place to have something wrong is the ground point, because this point is often connected to the ground plane with large-area copper, that is to say, their heat dispassion is good, you have to heat the solder to a high temperature, may be ~400 degrees Celsius, otherwise, the tin will not soak into the electrode which means dry joint and unreliable. For the mini-module, they are totally surface mount, dry joint is more easy to take place, compared to the larger module.

Dry joint is just a guess. You can firstly follow Spirit's advises. If the problem still there, you can consider the dry joint. And the easiest step is to replace the mini module by a larger one.

Good Luck!

[pataga]

I've used an AI Thinker ESP32-C3M module. Ref the AI Thinker datasheet schematic it had IO8 internally pulled up to VCC as bootstrap requirement for spi boot.

You have IO8 going to the LED anode, maybe it is a bootstrap issue.

[shivdeepak]

Thanks for all the responses. I was able to figure out the issue.

@ESP_Sprite based on your recommendation, I used a logic analyzer, and found out that the ESP32-C3 module was "Waiting for USB Download", while I was programming through serial. Thanks @pataga for your recommendation to look into GPIO8, I was able to fix the issue by pulling up GPIO8 with a 10k resistor.

Also, thanks @xien551 to telling me about dry solder joints. I decided to skip soldering by hand, and used solder paste, stencil and reflow oven instead.