ESP32-S3 is not booting, or is not even trying to

[preafixed]

Hi there,

I've been trying around for hours to get my custom made PCB to work, but it does not want to. I designed everything in Easy-EDA Pro, and ordered everything with all parts placed from JLCPCB, the board came yesterday. I have the following schematics:

schematic.jpg (553.78 KiB) Viewed 4443 times

schematic_1.jpg (251.95 KiB) Viewed 4400 times

Here is the assembled PCB:

20221231_122555.jpg (1.44 MiB) Viewed 4443 times

I wanted to build an ESP32 Cam myself, using the new ESP32-S3 model, instead of the old ESP32-S, that is discontinued but somehow still used in all ESP32-Cam chips. I have a few other schematic, but I don't think there is a problem with them, because one is for lipo charging (which works), one is for connecting the USB-C to the ESP32 with a CP-2102, connecting to the TX and RX of the ESP, and the other one is just a boost/buck circuit for generating stable 3.3V for the ESP (which works, too).

What I have done now is connected an USB-C cable to my PCB, I grounded IO-46 and IO-0 to boot to the bootloader. But I can't get a single signal from the ESP, the desktop ESP-Tool does not recognize it, and I've tried to hook up the RX/TX Pins of the ESP32, with an FTDI adapter whatsoever but nothing works.

It would be very kind if someone could help me? If you want the other schematics or the PCB design itself, just ask.

THANKS

[ESP_LJH]

So you could not see no log through TX RX, right? Do you make sure if TX RX are connected correctly? Could you make sure current requirement is met? I think you could provide complete schematic to us.

[preafixed]

Hey there,

here are all my schematics (I unfortunately can not post more than 3 images on here for whatever reason so I uploaded it to imgur:

https://imgur.com/a/r7bCllL

If anybody can find something wrong, I would be so happy. My other thought would be, that in my PCB Design itself I made some wrong connections, let me know if you need that to (the gerber file itself)

I tried to solder wires to TX and RX and hook up a CH340C, a FTDI Adapter, but nothing shows any output. I think that maybe the ESP32 is not even booting but I can't be sure. Someone knows how I can troubleshoot that?

[ESP_LJH]

all your schematic pictures are not seeable, could you upload schematic in pdf? or you could send your queries to sales@espressif.com, it is more convenient to send files.

[preafixed]

Here you go Sir,

I uploaded a PDF containing the Files

[ESP_Sprite]

For one, TX of the CP2102 should go to the RX of the ESP32 and RX of the CP2102 should go to the TX of the ESP32. (Also, on your PCB design: don't put vias inside pads. When in production, they can wick away the solder from the pad, making a bad connection. It can be worked around by plugging the vias, but that's usually expensive.)

[preafixed]

Hey,

thanks for your reply! I will remove the vias. Can you explain why I need to connect RX to TX and TX to RX? Would you recommend to build a circuit for RTS and DTS like here?

https://i.stack.imgur.com/Jtx4J.png

And do you know why my ESP32 is not responding or how can I tell that it is trying to boot?

Thank you

[ESP_Sprite]

Hey,

thanks for your reply! I will remove the vias. Can you explain why I need to connect RX to TX and TX to RX? Would you recommend to build a circuit for RTS and DTS like here?

https://i.stack.imgur.com/Jtx4J.png

And do you know why my ESP32 is not responding or how can I tell that it is trying to boot?

Thank you

Because on both the ESP32 and the CP2102, TX is the line that sends data (=output) and RX is the line that receives data (input). If you connect TX to TX, you're shorting two outputs, and if you connect RX to RX, neither device will be able to receive anything. That's the (or at least one) reason you don't get anything out of your ESP32: if it's trying to say something, your CP2102 is miswired so it can't receive it.

You can build that auto-reset circuit if you want to, your choice. Another option would be to forego the Cp2102 entirely and use the internal USB port of the ESP32-S3 to program/debug the chip; see here for more info on that.

[preafixed]

THANK YOU SO MUCH!! Never would've thought of that, I was literally just about to throw it away but now i removed the CP2102 with a knife and sand paper (XD) and soldered wires to RX and TX to hook up to a CH340C. BUT

Now I get this when I read Serial Monitor with BAUD 115200 (I tried different BAUD's too but no success):

serial_monitor.jpg (24.46 KiB) Viewed 4197 times

And when I connect IO46 and I0 to ground, I get this message:

serial_monitor_1.jpg (22.01 KiB) Viewed 4197 times

Any Idea why it is so obfuscated? And esptool says on upload, that no Serial Data was received so maybe it still does not boot to the bootloader right?

[Craige Hales]

How long are the TX and RX wires? Good common ground between the test circuits? Good power supplies?
You are really brave to try this without a scope. Even an old analog scope (in my case) will give insights about voltage levels, active signals, and noise.

I'm in the middle of a similar project, though I went with a 2 layer 100mm X 100mm board and hand soldered a wroom-32E because it isn't one of the basic parts...and was going to run the cost up a bunch. I also bought a couple of USB-to-serial devices for the serial and JTAG ports. Still had to get the TX-RX right.

I found this useful to pre-test/pre-load the wroom: https://www.amazon.com/dp/B08PKZ8SYP
This for the JTAG connection: https://www.amazon.com/dp/B09XTF7C1P
This for the serial connection: https://www.amazon.com/dp/B07BBPX8B8

The difference between the last two devices is one of them supports JTAG . The other has a nice case but only does serial. FT232RL vs FT232H. H is better.

I also upgraded my soldering station and invested in flux. It was easier than I feared. And now I understand why there are footprints for hand soldering...it is hard to get the pad hot if it is completely under the device.