modules not needing usb chips

[assegid]

I have seen boards like T7S3 that do not have usb chips. How do they work? Is it implemented in the esp32-S3-wroom-1-n16r8 module? if so, does the module come programmed ready to be used with a usb connector? if not, what is the procedure for making usb connectivity. Also, how does one identfy the modules that do not need external chips? Hope I am at the right place for the question.

[ESP_Sprite]

The ESP32S3 has built-in USB and you can use that to program/debug the chip. The details are in the datasheet/TRM, but thispage has the important bits.

[assegid]

Thank you ESP-Sprite. That was very useful.

[assegid]

which of the esp32 modules come with built-in USB. Is there a quick way to identify them?

[ESP_Sprite]

Check the datasheet of the chip and module. The chip datasheet will tell you if the chip has USB capabilities. (At this point in time, the ESP32-S3, -C3, -C6, -H, -P4 have USB-JTAG-serial, the -S3 and -S2 have USB-OTG) and the pins the USB signals are on. The module datasheet will tell you if these pins are available. (Generally, they will be available unless you get very specialized low-GPIO modules.)

[espcurt]

I'm working with an ESP32-C3 module (just the module) and dutifully wired up the D-/D+/GND to my PC and it does not recognize anything meaningful. It see's *something* and enumerates it as an "Unknown USB Device (Device Descriptor Request Failed)" but that's it.

I can flash code to it as normal over the TX/RX but the "build itn USB" seems to elude me. I have tried looking for drivers to no avail. Anything obvious and common I am doing wrong?

[ESP_Sprite]

Did you possibly swap the D+ and D- leads?

[espcurt]

I am embarrassed to admit that I did swap them. The silly thing is of course I tried them both ways and somehow came to the conclusion it did not work in either configuration. I assume some other problem prevented me from seeing it work with the correct polarity.

Once I discovered that everything started working as expected, marvelous little module here.