How do computers work?

Bravo

How do I interact with a kernel running on an FPGA?

If you want an easy to understand answer, it's going to be very simple, because modern computers themselves are incredibly complex and the result of decades of accumulation of knowledge and development from thousands of smart people, many of whom specialize in one particular component area of the computer and don't really know that much about the rest.

It's simple.
Computers are magic artifacts wielded by wizards. You'll understand once you turn 30.

it really depends how you've got your core configured. the kernel is a piece of software that runs in an embedded soft core(cpu+memory+glue letting them interact+peripherals) which is synthesized into an RTL tile configuration for the FPGA.

Since FPGA is very flexible, you could build a peripheral to support virtually any digital interface format, even emulating to use formats that your OS lacks drivers to support

with that said, if you're looking for a rrecommendation, an FTDI chip and UART are easy, although i know others who prefer ethernet and UDP

No one here knows because everyone things CS is for brainlets

other fields just jealous of our massive girthy throbbing compensation

Yeah, I wrote the post. Yeah, I agree with you.

Now this mother-fucker , this user is a savant, simply inspirational.

In fact, I have been carrying a heavy load around with me. I think it is about time to have a little confessional between me, my mini popes, and a nice box of smooth, lavender scented Kleenex.

agree
his autism gives him powers above and beyond mere mortals

black is ground you microbrain