ESP32-S3 USB JTAG and MSD

[steaky1212]

Hi everyone,

Is it possible to use the USB port for both JTAG and MassStorageDevice (or CDC)?

This can either be:

• it enumerates as a composite device
• for the first 10 seconds of booting it is JTAG, but then switches over to MSD if nothing has connected

I am using the ESP32-S3-Mini and I'm using every pin, so I can't use the external JTAG interface.

[ESP_Sprite]

The first option is impossible, as USB-serial-JTAG (which provides the JTAG connection) and USB-OTG (which can provide the mass storage functionality) can't be connected to the USB pins at the same time. The second option is viable.

[steaky1212]

It's good to know that option1 is impossible due to silicon!

Regarding switching out JTAG for MSD during run-time, would this just be a case of not running "tinyusb_driver_install" (etc.), or something a lot more involved?
Also, is there a way for the ESP32 to know that it is currently under JTAG and so to not enable the USB?

Thanks

[ESP_Sprite]

Regarding switching out JTAG for MSD during run-time, would this just be a case of not running "tinyusb_driver_install" (etc.), or something a lot more involved?

I think so, yes. Until that call, the usb-serial-jtag should still be available.

Also, is there a way for the ESP32 to know that it is currently under JTAG and so to not enable the USB?

There is: https://docs.espressif.com/projects/esp ... _attachedv