Meaning of routing and pin assignment for UART

[yefj]

Hello, I am trying to understand the link between the two parts of this UART example code which is taken from the link bellow.
At first we set PORT C pint 1 to be RX input and port C pin 0 as output(push pull amplified)
What exactly happens next in the USART-> ROUTE line?
I see bitwise OR but i can see how its linked to the locations we defined previosly.
Thanks.

peripheral_examples/series0/usart/async_polled/src/main_s0.c at master · SiliconLabs/peripheral_examples

Simple peripheral examples for Silicon Labs EFM32/EFR32 Series 0, Series 1, and Series 2 devices - SiliconLabs/peripheral_examples

github.com

 

[FvM]

For an detailed explanation, read the processor reference manual. In a short, writing to the USART1->ROUTE register is activating the above configured pins. The processor as several sets of dedicated GPIO pins that can be selected for the USART by a specific location code. The present code is apparently using default location 0, unless the LOC bits in USART1->ROUTE haven't been set differently before.