Adding a UART tab.

[mithro]

Fixes #33.

Follows the instructions from
Booting Linux on Tiny Tapeout 6 - KianV RISC-V SOC

See screenshot below;

[mithro]

I probably want to add a Ctrl-C button, which sends a Ctrl-C.

Also wondering if the UART tab should only show up when certain projects are selected?

[mithro]

[urish]

Thanks Tim! Moving between the REPL and UART tabs creates some inconsistent state:

UART -> REPL:

REPL -> UART:

The later one could probably be solved by sending a Ctrl+C one or twice to ensure no code is currently running and the REPL line is empty. Not sure yet about the former one.

As for Ctrl+C: yes, that'd be great.

Note that we don't really have to stick to the same method we used in Booting Linux on Tiny Tapeout 6 - KianV RISC-V SOC. We have full control of the terminal, so we could introduce some escape sequence, like , and then double every backslash we get as an input, and use something like \3 for Ctrl+C, then do the opposite translation on the micropython side.

When to show the UART tab - good question, it'll probably be confusing if the project doesn't support it (or use a different pinout). We can have a whitelist of projects that we know work with UART, and disable the tab when the project isn't on the list.