textfiles/computers/add5.25drive.txt

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HOOKING A 5.25" DRIVE TO YOUR AMIGA
by Les Ayling
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Hooking up a standard 80 track, double-sided, 5 1/4" floppy disk drive
as drive df2: or df3:
Looking at the connector from the back side of the external drive, the
pin out is as follows:
712 11 10 9 8 7 6 5 4 3 2 1
23 22 21 20 19 18 17 16 15 14 13
34 Pin edge connector pin-out is as follows:
34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2
33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
Wire a DB25 (RS-232) connector with pins 13 and 25 cut off per the
following configuration:
34 Pin 23 Pin
-----------------
34 --------- 1
32 --------- 13
30 --------- 2
28 --------- 14
26 --------- 15
24 ---7---- 16
22 --------- 17
20 --------- 18
18 --------- 19
16 ---------
14 --------- 9
12 --------- 21
10 -- tie to ground, keep the motor running all the time
8 --------- 22
6 --------- 20
4 ---------
2 ---------
all odd numbered pins of the 34 pin connector should be tied to pins
3, 4, 5, 6 & 7 of the 23 Pin connector (grounds).
In addition, pin 11 of the 23 pin connector should be wired to a
momentary push-button that can be activated whenever a diskette is
removed and replaced with another. This tells the DOS that a different
diskette has been inserted into the drive. Simply change the diskette,
push the button and hold until DOS accesses the drives. The switch may
then be released. This function is necessary due to the fact that the
DOS seems to read the directory of the current diskette into ram, and
unless the DOS is told of another diskette being used, it will either
ask you to replace the diskette that was in the drive or write to the
diskette using parameters from the previous disk. This, of course, is
very undesirable.
Also, note that the drive must be connected when booting DOS or it
will not be noted as being on-line. The diskette does not have to be
inserted, just the drive plugged in.
Do not make any connections to the 23 pin connector, pins 23 or pin
12. These pins provide power to the Amiga drive 1 and may not be used
to power an external 5 1/4" drive. An external power supply must be
used.
The 5 1/4" drive selection header may be programmed as drive for drive
2. Drive 1 selects as DF2: and drive 2 selects as DF3:.
A motor on latch circuit may be built to eliminate the motor
continuously turning, however, the way indicated above is the quickest
and simplest method to get another drive on-line.
After this procedure is completed, the 5 1/4" drive may be used just
as any normal Amiga drive.
Considering the $295.00 list price of the Amiga drives, versus about
$50 dollar price of 5 1/4" drives, it's a real bargain.
*** As always, with any hardware project -
(1) - if you are not sure of what I am talking about, get
knowledgeable help and
(2) - TRIPLE CHECK your work before plugging in the new drive.
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