[syslinux] interacting with UART

[Ferenc Wagner]

Tal Lubko via Syslinux <syslinux at zytor.com> writes:

> What I'm planning to do is to write COM32 image that will open UART
> channel and wait for input (until timeout arrives).  In case input
> arrives, it will parse and validate it and act accordingly.

> My solution doesn't involve user interaction.

This is exactly what the Syslinux command interpreter does, if it's
configured to use a serial console.

> My solution doesn't involve user interaction.

Your "user" is anything that feeds the serial input to Syslinux.
Whether it cares about the output from Syslinux, does not really matter
(unless it blocks Syslinux with flow control).

> I've searched the page you've sent me and it talks about serial
> console and I'm not sure I can use it for my needs.

If you can prescribe what the other end sends though the serial line in
the various cases, you can issue arbitrary Syslinux commands on the boot
prompt, and you're pretty much done.

If the other end sends stuff the command interpreter (or menu.c32) can
not digest, you can write a custom COM32 module which reads from the
"standard console" stdin (be it an AT keyboard or a serial line), and
implement your own parsing and business logic inside that.  Or you can
write a Lua script to do the same, and then you don't even need to
compile anything.

> So what I'd like to know is, does Syslinux supports UART in COM32
> image?

I think generically it does not.  But there's nothing to stop you from
reprogramming the UART syslinux_serial_console_info() points you at.  Or
another one.
-- 
Regards,
Feri.