Undocumented SIO Commands

[Steven J Tucker]

Is there any refrence for information on the undocumented SIO commands?

I recently added support to my software for the spartados $66 'format
ultraspeed skew' command and noticed that it also attempts to use
a command '@' when booting up.

Is the '@' command directed at some HD interface or time device? Any help
would be great.

Also, there seem to be alot of undocumented 1050 SIO calls. Ive seen
alot of them while using the 1050DIAG program. These include
$23, $24, $FE and a few others. Any ideas?

Thanks

Steve

[Ivo van Poorten]

clas...@en.com (Steven J Tucker) writes:

>Is there any refrence for information on the undocumented SIO commands?

>I recently added support to my software for the spartados $66 'format
> ultraspeed skew' command and noticed that it also attempts to use
> a command '@' when booting up.

>Is the '@' command directed at some HD interface or time device? Any help
> would be great.

I think it's a so called 'Percom command'. It's not a standard 1050 SIO
command.

>Also, there seem to be alot of undocumented 1050 SIO calls. Ive seen
> alot of them while using the 1050DIAG program. These include
> $23, $24, $FE and a few others. Any ideas?

$23 and $24 are internal diagnoses commands. Can be used to do all sort of
things like moving the head half a track forward and backward, see what's
the rpm etc.etc. I once wrote a small program which formatted a disk twice,
once starting at track -1 and once starting at the normal track 0 position.
Now I could put 26 sectors in front of track 0 which remained there even
after reformatting the disk. Could be used as sopme sort of copy protection,
though I doubt if all drives will recognise the $23 and $24 commands.

>Thanks

>Steve

Ivo

[Rick_Micha...@cup.portal.com]

Steve; you got me thinking so I pulled out my 1050 field service manual &
looked at the source code listing. Couldn't find any of the cmds you talk
about, but not willing to let it die, I put a Tandon ROM in my eprom burner
& dumped it. Not a single byte matched the source code, arrgghhh! Anyway
there's supposed to be at least two Tandon ROMs that I know of, E & F so
I was probably sold the listing for revision A<g>. Anyway, one of the reasons
the Tandon ROM was revised for the 1050 was because it returned different
values for errors under some forms of copy protection. Ivo seems to have it
cornered but I did a quick list of the command tables for the Tandom &
ICD ROMs
ICD !"PRSWNO?f
Tandon RPWS!"#$
I didn't bother to disassemble the binaries to try & figure out just exactly
what they were doing, but you do seem to be right on as far as undoc'd
commands go. The ones you mentioned aren't in the SD Construction set manual
so maybe I can find my 810 source list & see if it's in there.
Rick