TI-H: the first REPRODUCED ACPlay

To: ti-hardware@lists.ticalc.org, aklug@aklug.org, acplay@gussie.alaska.net
Subject: TI-H: the first REPRODUCED ACPlay
From: Grant Stockly <gussie@alaska.net>
Date: Sat, 17 Oct 1998 18:06:38 -0800
Delivered-To: ti-hardware-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: ti-hardware@lists.ticalc.org


Marc Wetzel of Germany as of today downloaded the plans and source code to
the ACPlay hardware mpeg player (files at http://gussie.alaska.net) and
reproduced a working version.

He is soo happy and can't wait for his 14.7456MHz osc to come in.  Right
now he is at 12.5MHz and all of the music comes slowly.

Marc is quite skilled at electronics like I, so I don't suggest that the
faint of heart try to do this.  It took a little IRC debugging session to
get things straight with the DC/DC converter (PUP/WSEN weren't happy).

The security thing at the AKLUG meeting today was great.

If you don't know who I am, I was the kid who had to change seating when
the bar opened.  Not the realy big guy, Ryan.  :)

The readon Macs running 8.5b6 or higher is because all of the Macs routines
are stored in the 'ToolBox' which is in ROM.  Starting with 8.5b6, ROM is
copied into RAM for faster access.  Now, apple can change any part of rom
just by patching the ram after the rom is copied over.

The reason all apps aren't compatible is because apple gives you two
routines to call...  year in xx and year in xxxx.  Most programs get the
year in xxxx and strip the first two digits off, but some old shareware
calls the xx routine to save time.

MKLinux, I run this on my G3, doesn't copy ROM to RAM, so 2038 just like PC
linux, is a bad date.  Since the last version of MK I have is beta 3, this
info is old.  The extended time fix is only a pointer to a place in ram
where the new routine exists.  Writing the code in assembly won't take long.

I'm an assembly programmer, so please don't send me C code.  :)  I also
prefer RISCy code.  ;)

Jared is working on the linux drivers for the parallel port.  Also might do
a conversion to dos.  One thing I want him to do is add a randon feature so
that it can randomly choose files from a directory and pipe them to the
parallel/serial port.  But between each file, it must play a set filename
"FCC.mp3".  I don't know if jared either wants or needs help, but I'm sure
he wouldn't mind.

Next time I come to the meeting I'll bring it.  I don't have a mac version
at this time since every mac that is 66MHz or faster plays MPEG bitstreams.
66MHz to 100MHz Intel's have problems.  Not to mention 386 computers.

I could whip up a serial version for 7 year old macs, but with 200MHz 603s
at $399, whats the point?  :\

Oh well...

Grant