Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!math.fu-berlin.de!fauern!unido!ipsi!wallmann
From: wallmann@ipsi.UUCP (Georg Wallmann)
Newsgroups: comp.sys.atari.8bit
Subject: Re: Homemade MIDI Interface -- Part 2 of 2
Message-ID: <1552@ipsi.UUCP>
Date: 8 Apr 91 16:53:56 GMT
References: <67653@eerie.acsu.Buffalo.EDU> <67656@eerie.acsu.Buffalo.EDU> <4484.27f222d7@miavx1.acs.muohio.edu> <68434@eerie.acsu.Buffalo.EDU>
Reply-To: wallmann@bern.UUCP (Georg Wallmann)
Organization: GMD Darmstadt (MSD/NAT)
Lines: 78

In article <68434@eerie.acsu.Buffalo.EDU> terpin@acsu.buffalo.edu (christophe d terpin) writes:
>In article <4484.27f222d7@miavx1.acs.muohio.edu> rlcollins@miavx1.acs.muohio.edu (Ryan 'Gozar' Collins) writes:
>>After seeing the diagram for the MIDI interface I was wondering. How hard 
>>would it be to hook it up to an ST through the MIDI ports, and be abel to 
>>transfer data back and for? (Or even to use the ST as a pseudo disk drive 
>>for the Atari. I'd be willing to write the software for the ST, hopefully 
>>writing it as a DA so you can be using both your ST and your 8-bit at the 
>>same time.)
>>
>>Any thoughts or ideas?
>>

>It would probably be fairly easy. In fact, I originally used my interface as 
>an RS232 link to my IBM-PC to transfer data at 19200 baud.  The 8bit 
>software for this Null modem was virtually identical to the MIDI source code.
>The only differences were that it didn't insert the VBI timing marks during
>input ("recording") and the values for AUDF3 and AUDF4 were different.
> (I've seen a formula that relates AUDF3,AUDF4 to baud rate-- I believe it's in
>the Operating System listing.)
>
But to get any kind of speed better use the parallel port on the
ST and the (sadly overused) joystick ports and the serial port on the 8-bit. 
I have something like this working and the hardware is simplicity itself just a 
schmitt-trigger IC and two resistors (apart from the cables). Unfortunately
on the software side the ST is single-tasking, which takes some of the fun
away and my stab at making the ST multitask apparently fails with TOS 1.4,
although I haven't investigated that yet. If I get my head out of this
ocean of work to get some oxygen and maybe enough time to rewrite the server
for Micro RTX or MiNT I will release this stuff.

The server is unstable at the moment, meaning that you shouldn't try to
run programs while using the server on the ST.

Just to brag a little, this can be done:

N: device handler 98% SpartaDOS eq.
   with SpartaDOS 2.X, you can do stuff like
D1: N:    # typed from memory, syntax maybe not 100% correct
N: DIR
N: CWD N:E:/FOOBLE>BAR\TMP
N: COPY TMP/BIGFILE.DAT D8:
N: COPY D8:BIGFILE.DAT N:TMP
N: CREDIR LILO

Transferring DEGELITE.PRG (approx 150K) takes not much more than 15 sec
from RAMdisk to RAMdisk.


If you don't mind occasional crashes, I could send interested parties
the prototype server and device driver software (binaries only, sorry). 
Beats any Null modem transfer anytime, anyway!

Email to : XBR1DE7B@DDATH21.BITNET

Ah, yes and asking this for maybe the tenth time... "How does one write
a device driver for the X cartridge ?"


The interface BTW looks like this:

------- port a
                ------<<<>>>---------------- parallel port ST ----
------- port b

------- IRQ Pin 13 SIO  ---------<<<------- Strobe Centronics ----

------- Motor Pin 7or8 SIO -->>>-- 1K --+-[IC]-- Busy Centronics -
                                        |
                                       1K
                                        |
                                     Ground

As you may be able to tell, this makes using the tape recorder impossible.
TOO BAD! (har har)

Nat!
"If there's a new way, I'll be the first in line/But it better work this time"
[Mustaine]