RTS/CTS Lines Accidentally Transposed Between STM32H7 and GNSS Module

[Muruganandam]

Hi everyone,

I’m working on a design using an STM32H7 MCU communicating with a GPS/GNSS module over UART. Unfortunately, during board routing, the RTS and CTS lines were connected directly (RTS↔RTS, CTS↔CTS) instead of crossed.

I understand that for proper hardware flow control, they should be:

• STM32 RTS → GPS/GNSS CTS

• STM32 CTS ← GPS/GNSS RTS

At this stage, I can’t modify the hardware or rework the PCB, but I’d still like to maintain some form of flow control or transmission reliability if possible.

[Andrew Neil]

Just drive them "manually" as GPIOs ?

Is XON/XOFF (so-called "software" flow control) supported?

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@Muruganandam wrote:

but I’d still like to maintain some form of flow control or transmission reliability if possible.

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GNSS modules generally work fine without flow control ...