I have an Arty Z7-20 and I'm trying to figure out how to get arbitrary data from HDL in the PL to the PS, to be printed over USB UART. I've followed this tutorial and I understand how to connect GPIO to the PS and to print to a serial terminal, but I can't figure out how to send data from the PL to the PS.
Say I want to implement a simple CPU in the PL, that I can interact with through a serial terminal. How could I send, for example, the output of a program (like printing "hello world") run on the CPU in PL to the PS to then be output to a serial terminal, and vice versa (typing in the serial terminal to send data to the CPU in the PL)?
I want to do o this because I am interested in architectures, compilers, emulators and the like and would like to learn FPGAs by eventually implementing a CPU on the FPGA side. I've been stuck for so long by the USB UART being accessible only through the PS. I essentially just need a bridge on the PS to exchange data from the PL to the PC's serial terminal.
Thank you to anyone that can help!