esp32-s3 serial port over usb

[atx823]

One of the answers to another question https://esp32.com/viewtopic.php?f=2&t=28326 says:

The -S3 has both an USB-serial-JTAG device as well as a 'general-purpose' USB-OTG peripheral. The device you see on bootup is the USB-serial-JTAG unit; it does not need software to work and as such you can program the ESP32S3 directly from the factory.

On my linux box when I plug in a regular esp32 devboard with a cp2102 bridge I see a port /dev/ttyUSB0 appear.

When I plug in an esp32-s3 with a usb cable connecting D- and D+ to GPIO19 and GPIO20, I don't see any port appear. What port should I be using in this case?

[username]

Have you programmed it yet? If not, flash some code to it. You should see a port appear.
Also, another thing to try is use menuconfig and change "Channel for console output" to be USB Serial/JTAG Controler)
It under Component config -> ESP System Settings.

Rebuild, and flash it should work normally then.

[corz.org]

Yes, pop it into download mode and it should appear as /dev/ttyACM0 or similar.
Once you upload a sketch to it, it will operate more like normal.

[atx823]

No luck with this.

I reflashed with the menuconfig console output set to USB Serial/JTAG Controller, then plugged in the usb cable, rebooted with GPIO0 grounded. I have verified the sketch is running, but no new ports show up.

I've probed inside the female A end of the cable to verify the connections between D-/D+ and GPIO19/GPIO20 and everything is good.

Can't think of anything else to try.

[username]

When I plug in an esp32-s3 with a usb cable

What exactly are you plugging in? You own board design or a dev kit, or other ?

[atx823]

My own board design. It's pretty simple - just an ap2115 regulator, a usb4105-gf-a receptacle, a couple of headers, and some buttons for EN and IO0.

[username]

Ah, ok. IF you willing to post the schematic we can take a look.

[atx823]

Cool, thanks.

s3 schem.png (23.66 KiB) Viewed 5323 times

s3 pcb.png (224.11 KiB) Viewed 5323 times

[username]

Nothing jumped out at me for the USB connections.
Though, If I might nit pick. You really need to add caps on that board.
There should be at least a 0.1uf cap on the input to the regulator, and output. Would be better to also include >4.7uf to them as well.
I did a board similar 2 weeks ago, and It worked just fine.

Mini_skiz.png (215.4 KiB) Viewed 5310 times

Mini_pcb.png (74.86 KiB) Viewed 5310 times

[atx823]

Good point on the caps -- I'll add them. Thanks for taking a look.