QUERY · ISSUE

ESP32-C6, ESP32-S3, etc.: MICROPY_HW_ENABLE_UART_REPL should be disabled for boards that have both direct USB and UART connectors

openby bikeNomadopened 2025-07-13updated 2025-08-10

enhancementport-esp32

Description

On many ESP32 boards, there are two USB connectors: one connected directly to the MCU and the other connected via a USB/UART bridge chip.

The default ESP32 build for these boards puts the REPL on both ports, making it impossible to use the USB/UART connector as an independent UART for other purposes.

See discussion at #17633 .

Code Size

No response

Implementation

I hope the MicroPython maintainers or community will implement this feature

Code of Conduct

Yes, I agree

CANDIDATE · ISSUE

esp32: UART(0) is disabled (dedicated to REPL)

closedby andcss93opened 2018-05-21updated 2022-05-18

Hi @dpgeorge,
in response of to the pull request #3784 relative to the dupterm of the esp8266, my need is to use the UART(0) it's not because the other ports are in use, but because my society production version of the board esp32 use RXD0 and TXD0 to communicate with the device.
By now the esp32 was produced so we can't change the hardwere, is there any way to detach the UART(0) from the REPL using the dupterm function?

I hope i made my point.
Thank you for your reply in advance.

Assessment

S Sonnet · high

Both issues concern UART(0)/UART REPL on ESP32 blocking use of those pins for other purposes, but they differ in scope and proposed resolution. #3805 is about a production board needing RXD0/TXD0 for device communication and requests a runtime dupterm mechanism to detach UART(0) from REPL. #17672 is specifically about boards with dual USB (direct MCU USB + UART bridge) where the UART REPL is redundant because USB provides the REPL, and requests a compile-time per-board configuration flag (MICROPY_HW_ENABLE_UART_REPL). The root symptom overlaps (UART tied to REPL, can't use it for other purposes), but the contexts differ: #3805 is hardware-constrained arbitrary UART use, #17672 is about board-level defaults for a specific hardware topology. Neither resolves the other.

Suggested action

Cross-reference these issues when addressing either. A solution to #17672 (per-board MICROPY_HW_ENABLE_UART_REPL) would partially address #3805 for users able to recompile, but #3805 also asks for a runtime/dynamic solution. Link the issues to consolidate discussion, but keep both open as they represent distinct asks.