USB CDC auto boot and auto reset (without BOOT / RESET buttons)

[lam90@yahoo.com]

I'm trying to design a custom board with ESP32 C6. The code needs to be uploaded to bare chip using USB CDC and cannot have manual intervention to press BOOT and RESET. Is there any references schematic that shows how to auto BOOT and auto RESET with USB CDC?

[Sprite]

The USB-serial-JTAG device in that chip generally handles auto-reset by itself, but as it's part of the SoC, there are exceptions: e.g. on a failed flash or when firmware reconfigures the USB pins into something else, or when the entire chip is put into deep sleep without a wake trigger, it doesn't work. If you need auto-reset that always works without buttons, you're better off using an external USB-serial chip with the auto-reset two-transistor circuit commonly found on ESP32 boards.

[lam90@yahoo.com]

Thank you for your answer. I suppose the reset would work for me even with the limitation since it is supported by the SoC. Question is, how do I enter into the boot mode so the native USB can be used without a boot switch?

[Sprite]

The USB-serial-JTAG device should generally work without needing to enable it, and it can reset the ESP32 via the USB protocol.