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How do I configure an Rx only UART interface in cubeide?...

JHoun.1
Associate III

I dont want to 'waste' the pins on the Tx line as this will not be used (the datastream is one way from an RC receiver into the STM32) - This isnt a case of it being a half-duplex etc.

I can set the direction of data to be receive only in the advanced parameters section, but the Tx pin continues to be displayed on the chip annotations and if try to reassign the Tx pin to something else (like a standard GPIO) I lose the whole of the UART interface.....

Thanks in advance for your help.

James

5 REPLIES 5
TDK
Guru

Mode: Single Wire

Data Direction: Receive only

In this mode, it uses the TX pin to receive and transmit.

As soon as HDSEL is written to 1:

• the TX and RX lines are internally connected

• the RX pin is no longer used

• the TX pin is always released when no data is transmitted. Thus, it acts as a standard

I/O in idle or in reception. It means that the I/O must be configured so that TX is

configured as floating input (or output high open-drain) when not driven by the USART.

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Piranha
Chief II

Using only receiving functionality with Rx pin is completely valid use case. Don't use CubeMX non-working bloatware generator and you'll not be limited by it's stupidities.

I'd formulate slightly differently: Cube, and its configurator, CubeMX, inevitably cover only a limited subset of possible usage modes - those, which were envisaged by their authors as the "most common ones".

The clicking "magic" stops working immediately if you want something out of this limited set of modes, even if it as a trivial thing (such as simply not using setting the Tx pin in GPIO).

Ditch Cube, start programming as an adult.

JW

This assumes I can start programming as an adult. This is only a hobby for me, time is limited and precious and so when shortcuts are there (like cubemx generating the setup code) they need to be taken if possible - and to the point where I would use an MCU with higher pin count to avoid not being able to take this short cut.

I understand what you are getting at though.

po221
Senior

I have the same problem, it's a shame to discover this limitation on the last pin of the last feature of my application.

Yet I feel like I'm coding like an adult harnessing the power of cubeMX.