Enabling UARTx on 40-pin header

Hello,
I’m trying to port a Python application from Raspberry PI to Cubie A5E but I need to use an UART to connect the board to an external device. If I list /dev/tty* I can see ttyAS0 and ttyAS1, are these ports correspondig to some UARTs on the 40-pin header? If not, how can I enable the hardware UARTs on the Debian 11 xfce system?

Thanks in advance,
Francesco