ESP32 Forum

Posted: **Tue Aug 20, 2024 10:04 pm**

Hi

I have made a custom PCB with an ESP32-C3-WROOM on it and wish to use it with the USB-JTAG for programming. However, whenever I connect it to the computer it throws errors and is not recognized as a COM/TTY port. Errors seem to indicate it could not properly communicate with the ESP32.

I am at a slight loss as to why though, I have followed the datasheet and I don't seem to be able to spot any errors. D+ and D- are connected as well as USB power and GND. Also looked at reference designs using ESP32-C3s like the rust-dev kit, and from what I can tell I have the same connections.

I have tried both on Linux and Windows, but none of them recognizes it as a valid USB. Neither when powering it in the download mode, nor in normal operation.

I have tested that the ESP32 does seem to work as when I connect an FTDI cable to the TX/RX and boot the ESP into download mode I can program it through the FTDI cable.

I have a feeling that it is somewhere between my USB connector and the connection to the ESP32 that it goes wrong. But I am not sure if I have routed the signal wrongly or have some EMC or interference that kills the signal. Any help would be appreciated

I have attached my schematics and board top and bottom copper layers.

Posted: **Wed Aug 21, 2024 2:47 am**

Does it also do this if you put the chip into bootloader mode manually (i.e. press and hold boot, then press and release reset)? Under Linux, what does 'dmesg' say after you plugged in the device?

Posted: **Wed Aug 21, 2024 7:53 am**

yes. Tried manually as you described, or keep the boot button down while plugging it in.

dmesg gives:

Code: Select all

[232515.423077] usb 1-1: new full-speed USB device number 25 using xhci_hcd
[232515.551097] usb 1-1: device descriptor read/64, error -71
[232515.787315] usb 1-1: device descriptor read/64, error -71
[232516.023174] usb 1-1: new full-speed USB device number 26 using xhci_hcd
[232516.151259] usb 1-1: device descriptor read/64, error -71
[232516.387303] usb 1-1: device descriptor read/64, error -71
[232516.495155] usb usb1-port1: attempt power cycle
[232516.907174] usb 1-1: new full-speed USB device number 27 using xhci_hcd
[232516.907348] usb 1-1: Device not responding to setup address.
[232517.115390] usb 1-1: Device not responding to setup address.
[232517.323252] usb 1-1: device not accepting address 27, error -71
[232517.451093] usb 1-1: new full-speed USB device number 28 using xhci_hcd
[232517.451453] usb 1-1: Device not responding to setup address.
[232517.659933] usb 1-1: Device not responding to setup address.
[232517.867111] usb 1-1: device not accepting address 28, error -71
[232517.867205] usb usb1-port1: unable to enumerate USB device

But as said, using the FTDI cable on the RX/TX pins works fine when manually putting into boot.

Posted: **Wed Aug 21, 2024 11:38 am**

That conks out really early in the detection process... given the fact that the device is detected as a full-speed device, I think your D- USB line may have issues.

Posted: **Wed Aug 21, 2024 12:32 pm**

Thanks for looking at it!

I will try to look further into the D- line and see if I can find anything wrong with it, and try to solder a direct wire etc.
Anything that jumps into your mind I should be looking for with the D- trace as potential trouble?

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