CubeMX 6.16.0 Forces TX Pin Configuration for RX-Only UART (e.g., SBUS) — Bug or New Feature?

[BJX]

Hi everyone,

I've noticed a change in UART pin configuration behavior from CubeMX 6.10.0 to 6.16.0 that has caused a practical issue:

Before (v6.10.0): It was possible to configure only the RX or TX pin for an asynchronous UART, enabling "receive-only" or "transmit-only" modes.
Now (v6.16.0): Both TX and RX pins must be assigned simultaneously; otherwise, the UART peripheral cannot be enabled.

Problem: This wastes a GPIO pin. My specific use case is an SBUS receiver (one-way communication, requiring only the RX pin). Now I'm forced to allocate an additional TX pin that will never actually be used.

Questions:
1. Is this a permanent new requirement in CubeMX, or is it a GUI bug in version 6.16.0?
2. What is the technical reason behind this change?
3. Is there any way to achieve a true single-pin UART configuration under the new version?

Thanks for any insights.

[TDK · Accepted solution]

Use single-wire mode if you only want a single pin assigned. It'll use the TX pin even to receive.

Don't think Asynchronous mode has ever let you not use both pins, even if you select transmit-only or receive-only. Certainly not in the past few years. Please include an IOC file of that if you want me to check it out.