System Booster/System Booster.iso/Archives/HardwareProjects/AddDF2.lha/AddDF2+3/df2+3.txt

Text File | 1995-06-25 | 8KB | 194 lines

    Some Text about adding INTERNAL df2: and df3: to a A1200 Tower
    or whatever.....

;--------

Legal and whatsoever things:

THIS INFORMATION IS FOR EXPERIENCED HARDWARE HACKERS ONLY. IF YOU DON'T KNOW
WHAT YOU'RE DOING, STOP IMMEDIATELY. I'D HATE TO SEE/HEAR YOU DESTROYING YOUR
AMIGA BY FAILING TO CONNECT THIS HACK TO IT. I WON'T ACCEPT ANY
RESPONSIBILITY OF HARD/SOFTWARE DAMAGE CAUSED BY THIS INFORMATION. IT'S YOUR
OWN RISK. I CAN'T GUARANTEE ALL DETAILS IN THIS INFORMATION TO BE CORRECT OR
VALID IN ANOTHER AMIGA.

WHAT COMES TO ME, THIS INFORMATION MAY BE DISTRIBUTED FREELY AS LONG AS
NOTHING HAS BEEN CHANGED IN IT. ARCHIVING PERMITTED.

;----------

Hi, I'm Troy McLure. You may remember me from 'How to replace a wall socket
without turning off the electricity' or 'How to get bumped by a car and
survive it'.

..eh... wrong topic. Sorry.

I've built an A1200R, rack-mount cased computer. It has a 200W PoWaSuPpLy,
two 3.5in hard disk sites (of which one populated), two 5.25in floppy
sites (of which one populated by CD-ROM drive), two 3.5in floppy sites (of
which ONLY ONE populated). Still, I can't connect more than one internal
floppy drive. Of course I could use external drive, but that's kinda... rude.
After all, I've got a case with enough floppy drive holes in its front panel!

That's gonna stop right now! I built a piece of hardware to get more drives.

The piece of hardware creates autoconfiguration signals to make Amiga recognise
the drives after reset and memorize if each drive's motor is on or off.
And, of course, get all drives supplied with PoWa and other signals, that
are common to all drives.

I'm not gonna bore you with any timing charts

1 -----     ---     ---     ----
       |   |   |   |   |   |
0       ---     ---     ---

or that $FFFFFFFF means no drive and $55555555 means a 3.5in drive and so on.
TTL ICs have never become familiar to me. I just looked, what pin to connect
to what pin and so on.... Raw 'schema' is in 'df2+3.pic', I got nothing better
than that to build my hardware, except that I got an A500 schematics to look
for details and make sure that connections at least made sense.
I built it on a piece of 'vero' board (that... printed circuit board, that
has a LOT of holes in it and just a teenie-weenie pieces of copper around
them) and it worked fine when I tested it.

Because this construction has many ways to fit it in your system, I'll just
explain the principle. You may want to connect only one extra drive, so you'll
build logic for only... say df3:.

Usage of 7474 (dual D flip-flop) is quite funny in this hack. Only half of
it is in use and there's two of them...

We'll lead all floppy signals from motherboard to df0: as usually.
Then we'll create _MOTOR2 and _MOTOR3 signals as well as _SEL2' and _SEL3'
and inject them to the same cable that connects df0:. That requires a special
(I mean a SPECIAL!) cable to be made. Otherways, however, we'd have to make
a PCB that contains three 34-pin connectors, one for incoming signals,
one for df2: and one for df3:. That would make usage of vero board rather
impossible. Since I don't have equipment for making two-sided PCBs, I
chose this way. All common signals continue from df0: to df2: and df3: and
we'll just add those _selects and _motors.
In our PCB's 34-pin connector  we'll connect _SEL2' to pin 10, _MOTOR2
to pin 16, _SEL3' to pin 12 and _MOTOR3 to pin 14. After df2:'s connector
we'll cut off _SEL2' and _MOTOR2 and re-route wire 12 (_SEL3') to pin 10 and
wire 14 (_MOTOR3) to pin 16.

Supplying PoWa to the extra drive(s) I'll leave to be your headache.

Making internal drives to be df2: and df3: instead of df1: and df2: makes
sense: Even if you have two extra internal drives, you can connect external
that becomes df1:.
If df2: of this hack is ON (JP(DF2) is connected) you MUSTN'T CONNECT MORE
THAN ONE EXTERNAL DRIVE, because otherways there would be two df2:s of which
NEITHER would work. In the worst case, Amiga's CIA, Paula or floppy drive(s)
would get damaged. To prevent this problem, you could cut off signals _SEL2
and _SEL3 from Amiga's external floppy connector. I didn't do it, I just
have to remember not to connect too many drives....
If JP(DF2) is OFF.... Go ahead.

Jumper JP(DF2) selects, if df2: will be reported to be present or not.
That's because if you build a board for both df2: and df3: and connect only
df2:, you'd see an icon 'DF3:??????????????????????????????' or something like
that in Workbench on next bootup.... and lose some valuable CHIP memory.
Not to mention that horrible waste of time on bootup, when trackdisk.device
tries to read bootblock from df3:... We're talking about 10 seconds here, man!

What else? Oh, I think I should convince you that this hack is worth building,
and that it works with me without problems.

    Yes, it is and Yes, it does: Look at this:


;------------------

Launched NewShell, process 11
11.Ram Disk:> diskchange df3:
11.Ram Disk:> df2:1541 DRIVE 3 FILENAME ram:ContentsOfOneC64Disk
1541 - Copyright © 1994 by Dan Babcock
11.Ram Disk:> getfiles ContentsOfOneC64Disk
getfiles - Copyright © 1994 by Dan Babcock
Converting ContentsOfOneC64Disk
    Disk name: DISK 6-SEP-90
    IS THERE A DIFF  PRG
    TIME CRYSTALS    PRG
    ABSOLUTE DEMO    PRG
    PBS DEMO 1       PRG
    LOAD AID         PRG
11.Ram Disk:> Jeeeee!!!!!!!!!!!!!
Jeeeee!!!!!!!!!!!!!: ?Redo from start.
11.Ram Disk:> ls df0:
Directory "df0:" on Friday 23-Jun-95
SCDPlayer11.lha            79643 ----rwed 19-May-89 12:04:43
YetAnotherCdPlayerV1.1.lha   62578 ----rwed 08-May-94 05:40:43
: *
amicdrom.lha              187595 ----rwed 08-May-94 05:42:01
amicdrom.lha.pi             1234 ----rwed 08-May-94 05:41:31
AmiCDRomV1.8.lha          108587 ----rwed 12-May-94 21:54:21
***Crash! Boom! Bang!
5 files - 867 blocks used
11.Ram Disk:> ls df1:
Directory "df1:" on Friday 23-Jun-95
move.lha                   15552 ----rwed 08-May-94 05:57:43
TrackDiskPrefsV1.0.LHA     22379 ----rwed 26-Jul-94 01:56:01
: Amiga Users' Fantasy 26-Jul-94 01:54:24
UND64373.lha                9414 ----rwed 11-Jul-94 01:07:19
: Extracts/list files in .d64 diskimages
***Crash! Boom! Bang!
3 files - 97 blocks used
11.Ram Disk:> ls df2:
Directory "df2:" on Friday 23-Jun-95
libs.info                   1249 ----rwed 23-Mar-95 14:27:26
1541                       17924 ----rwed 17-Jun-94 21:49:56
1541.c                     14214 ----rwed 17-Jun-94 21:49:12
1541.doc                    6281 ----rwed 17-Jun-94 14:13:54
getfiles                    9416 ----rwed 17-Jun-94 00:17:48
getfiles.c                  7410 ----rwed 17-Jun-94 00:17:10
***Crash! Boom! Bang!
6 files - 113 blocks used
11.Ram Disk:> ls df3:
No information for "df3:": not a valid DOS disk
11.Ram Disk:>

;----------

... so, all four drives were working. Df1: was external. Those strange error
messages stand for YourFault © Lee Kindness, Scotland. So, I used a 5.25in
drive to read an C64 floppy.

Only PC makes it possible... NOT! HEHEHEHEHEHE!!!!!!

;-----------

Possible problems dept.:

I've read that floppy connector's signals should be
terminated like SCSI bus. I have the cable of about one meter long without
trouble. If you get occasional read/write errors, terminating could be the
reason. At least in SCSI bus, terminating problems make ALL devices connected
to the bus not to work at all or work only whenever phase of the Moon is
right...

If one or several disk drive's indicator LED lights all the time and the
drive(s) don't work, some drive has its connector in the wrong way.

Connection of floppy power connector you can find out peeking one of your
drives.

If your coffee is too hot, you can pour some cold milk in it or let the coffee
cool down in the cup.

;----------------

Eh... I haven't mentioned my name, nationality nor address.

        Arto Niskanen
        Valtatie 8A8
        90500 OULU
..and that's in FINLAND

E-Mail:        [e-mail]!!!!!!!!!!