Matek F405-SE & USART ports, whats going on?!

I have a Matek F405-SE FC and it has two USART ports?!

I can’t get these USART ports working with GPS, Bluetooth connection. Once I move those devices to ‘normal’ UART’s ports all works. But what good are those USART ports, do they need to be configured differently?

Nope, all the same from a user persepctive

It has 5 UARTS and an additional serial Rx.

We I did try two different gps units on USART 3, don’t work. Move the gps to UART 5 all good, with the same gps setup/config

Its more likely that you need DMA for the GPS since it needs 230kbs by default. Not all ports have DMA