Subject: Re: Using Serial (SSC) from assembly
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From: Phoenyx <quazar@dcnet2000.com>
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Date: Wed, 04 Oct 2000 17:33:36 -0500
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> I was wondering if someone could explain to me how to access serial
> devices (null-modem) from assembly code.  I ran across the ADT source
> code.  It was of some use but I need the overview/specifics.  Of use
> could be some examples in action, as well.

Well, I don't have samples handy, but I will look for some. Programming
is similar to sending output to the standard video device. Ok, this is
a simplistic answer. Technically, you should scan each slot for the
existence of the serial firmware. Generally it is best to base the code
on the SSC if you have one since the 2c ports simulates this card. With
this in mind, you should check around for info on these cards.

For basic I/O from assembly, you replace the I/O hooks with the address
of the new output routine and restore the hooks when you are finished.
Then you simply send the data via the standard output routines such as
$FDED. Of course you can code your own routines and I think I have seen
info on this with either one of the current assemblers online or the old
Dos freeware assemblers disks. Again, I will have to look around.

Sorry, I know it's not much info, but I hope to find some more and can
get back to you with it. I'm sure that either Dave Wilson or Dave Empson
have better answers.

-- 

Thank you for your time and interest. I hope it was helpful
or at least interesting.

Phoenyx,

Apple2 user since March 1984

Links to Phoenyx's pages:
preferred..... http://zip.to/Phoenyx_A2
alternate..... http://www.tinyangeldesigns.com/Apple2