Summary

I was having an issue getting USB serial going on an ESP32S3 LilyGO T-Deck, the flavor that is called "Serial/JTAG mode" in Micropython (not the one where there's an explicit serial -> USB chip onboard.)

The REPL appears fine on the UART chip models. But on the T-Deck (and presumably other boards with no explicit UART chip) I cannot see or type into the REPL from the serial monitor.

If i set in mpconfigport.h:

#define MICROPY_HW_USB_CDC (1)
#define MICROPY_HW_ESP_USB_SERIAL_JTAG (1)

I get a compiler error: #error "Invalid build config: Can't enable both native USB and USB Serial/JTAG peripheral". OK, so for the T-Deck I turn off HW_USB_CDC:

#ifdef TDECK
#define MICROPY_HW_USB_CDC (0)
#else
#define MICROPY_HW_USB_CDC (1)
#endif

But then ports/esp32/usb.c has a #ifdef for MICROPY_HW_USB_CDC bracketed around the entire code, including usb_usj_mode which is required in the bootloader. So, if i'm understanding it right -- we can't have both USB_CDC and USB_SERIAL_JTAG on at once. Makes sense. But usb_usj_mode requires USB_CDC to be enabled to switch the PHY back to Serial/JTAG mode. That doesn't make sense to me. So this PR moves the #ifdef out of the way of usb_usj_mode.

Testing

With this, everything compiles fine and I'm able to use mpremote etc to control the T-Deck over Serial/JTAG.