QUERY · ISSUE

ESP32C6: USB not in board.json `features` but GPIO pins are disabled anyway

openby smurfixopened 2025-10-05updated 2025-10-08

enhancementport-esp32

Description

IMHO the default value for MICROPY_HW_ESP_USB_SERIAL_JTAG should be "is the USB feature turned on in the board.json file".

An even better default might be "micropython checks the EFuse flags and enables the pins iff these flags are set".

The relevant efuse bits are DIS_PAD_JTAG and DIS_USB_JTAG, see tech manual 9.2.4 "JTAG Signal Source Control" page 378/379.

Code Size

No response

Implementation

I would like to sponsor development of this feature

Code of Conduct

Yes, I agree

CANDIDATE · ISSUE

ESP32-C3 CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG=y disables repl on USB

closedby bdambrosioopened 2022-05-06updated 2022-05-06

On my ESP32-C3 boards (AI-Thinker, Espressif esp32-c3 devkit, and Espressif esp32-c3-wroom), I could only get repl on the uart RX/TX pins using the default GENERIC_C3_USB board defs.

I had to change to
CONFIG_ESP_CONSOLE_UART_DEFAULT=y
CONFIG_ESP_CONSOLE_USB_CDC=y
CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG=

and now I get repl on the USB.
Shouldn't this be the default, or am I missing something?

Assessment

Q Qwen · medium

Both issues concern USB serial/JTAG functionality on ESP32 chips (C6 vs C3) and involve board configuration. However, they address different specific problems: Issue #18213 is a feature request about making MICROPY_HW_ESP_USB_SERIAL_JTAG default behavior check board.json features or EFuse flags before disabling GPIO pins. Issue #8640 is a bug report about USB REPL not working on ESP32-C3 due to CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG being enabled. While they share the same component area (esp32/usb) and involve similar concepts (USB serial JTAG), the root causes and proposed solutions are different. #18213 proposes hardware capability detection, while #8640 is about console configuration defaults.

Suggested action

Keep both issues open as they address different problems. #18213 is a feature request for automatic hardware detection, while #8640 is a configuration bug for a specific board. They may inform each other but neither resolves the other.