Date : Tue, 08 May 2001 21:09:06 +0100
From : "Chris Thornley" <C.J.Thornley@...>
Subject: Re: 3.5" floppies and IDE hard-drives
There was a SERIAL RS423 16bit IDE Hard disk controller in elektor
electronics magazine a few months ago which might be of interest. It needs a
filing system written for it but is suggested would be ideal for old 8bit
computers or development projects. Back issues probably can be obtained from
your local library or by interlibrary loan.
http://www.elektor-electronics.co.uk/
I have an article about the various different pin conditions for floppy
drives they are slightly different and I have attached this as some of the
connections are non standard. Its in guide format but should be readable.
You probably have the force the drive to use a slower seek time I believe
someone has a software DFS patch to do this or has the keyboard links which
might be of use.
Chris
@... "Pin layout" "Pin layouts"
@...{u}Connections & Connectors@{uu}
In this @{"picture" system "run >NIL: multiview Connections.iff"} you can
see the connections
@...{u} Connections to PC drive (34 pins Shugart bus)@{uu}
The connector for the power supply consists of 4 pins:
@{u} pin 1:@{uu} 5 volt
@{u} pin 2:@{uu} Ground
@{u} pin 3:@{uu} Ground
@{u} pin 4:@{uu} 12 volt
It is important not put this connector in the wrong way. You probably will
wreck
your drive !!! Normally it should be very difficult to do this, but I can
assure
you it can be done. Just try it out with the power off and see for yourself
which way fits best. By the way I read that for the 5.25 inch drives with
the
bigger connectors pin 1 is 12 volt and pin 4 is 5 volt !!
I checked out some books and magazines to give you some detail on the drive
connector. Only the even number connections are used for signals. The odd
numbered pins are connected to ground.
@{u} PIN 2:@{uu} DISKCHANGE Output signal. This is a tricky one to start
with. It is
used for a number of different signals by each manufactorer. The first one
is
the most widely spread used. DISKCHANGE is perfect to use for the amiga
diskchange signal. HIGH DENSITY/DOUBLE DENSITY input signal to switch drive
motor between 300 and 360 rpm. Only used for 5 1/4 inch floppy drives. IN
USE
input signal for letting the drive know something is coming up soon. Also
used
for driving led at front of the drive. HEAD LOAD input signal for the drive
to
put the head to the disk and pre magnetise it. (Rarely used)
@{u} PIN 4:@{uu} IN USE Another pin use in more ways than one IN USE is
the most likely
candidate. see pin 2 (Sometimes you can have DISKCHANGE and HEAD LOAD). With
internal Amiga drives IN USE is always connected to the MTRX signal. So when
the
motor is spinning the LED is on.
@{u} PIN 6:@{uu} DRIVE SELECT 3 see PIN 10. Pin 6 is sometimes used for
the READY
signal (see PIN 34).
@{u} PIN 8:@{uu} INDEX output signal will be low when the magnet on the
flywheel of the
drive passes the Hall sensor (when drive SELECT is low).
@{u} PIN 10:@{uu} DRIVE SELECT 0 input signal for selecting the last drive
which is
then connected to this line. You will have to get the drive jumpers set to
the
drive select you want. Normally the drives are left with the jumper on
SELECT 0
and the cable is twisted to change select lines (Yes that's why there is a
twist).
@{u} PIN 12:@{uu} DRIVE SELECT 1 see pin 10
@{u} PIN 14:@{uu} DRIVE SELECT 2 see pin 10
@{u} PIN 16:@{uu} MOTORON input signal switches to motor on. Sometimes the
amiga way of
switching on the motor with DRIVE SELECT can be set with a jumper on the
drive.
@{u} PIN 18:@{uu} DIRECTION SELECT Input signal. When low stepping
direction of the
head is to the axis (inside) of the disk. High is to the outside of the
disk.
@{u} PIN 20:@{uu} STEP Input signal. With every low pulse the head is
stepped to the
next (by pin 18 determined) track when the drive is selected.
@{u} PIN 22:@{uu} WRITE DATA Input signal. Here the data to be written on
the track is
coming in from the computer.
@{u} PIN 24:@{uu} WRITE GATE Input signal. When low the data from pin 22
is written on
the disk.
@{u} PIN 26:@{uu} TRACK 0 Output signal. When the head is above the first
track this
line will be low when SELECT is active.
@{u} PIN 28:@{uu} WRITE PROTECT Output signal. When the write protect hole
is open
(disk is write protected) and SELECT is low this signal will be low.
@{u} PIN 30:@{uu} READ DATA Output signal. When SELECT is low then the
data on the
track is written to this line.
@{u} PIN 32:@{uu} SIDE 1 SELECT Input signal. When the SELECT is active
this line set
the head (upper or lower) on which side is selected.
@{u} PIN 34:@{uu} READY Output signal. Low when SELECT is active and the
disk is
spinning at the right speed (INDEX signal) or, in a older simpler version,
if a
disk is in the drive. It tells the computer that the drive ready to do a
read or
a write of the track. The signal is high when the drive is empty (no disk),
when
the motor isn't running or the motor is running too slow. Also very shortly
after a Head step signal it is high (15 ms). You see in this way the drive
is
not mounted by the amiga! (Rarely used as DISKCHANGE or IN USE).
@...{u} The amiga floppy connector (@{uu} external, 23 pins D-sub bus MALE)
PIN 1: RDY READY
PIN 2: DKRD read data
PIN 3: GND ground
PIN 4: GND ground
PIN 5: GND ground
PIN 6: GND ground
PIN 7: GND ground
PIN 8: MTRX motor
PIN 9: SEL 2 select drive 2
PIN 10: DRES drive reset
PIN 11: CHNG diskchange
PIN 12: +5 volt
PIN 13: SIDE side (head) select
PIN 14: WPRO write protect
PIN 15: TK0 track 0
PIN 16: DKWE write enable
PIN 17: DKWD write data
PIN 18: STEP step
PIN 19: DIR step direction
PIN 20: SEL3 select drive 3
PIN 21: SEL1 select drive 1
PIN 22: INDEX index
PIN 23: +12 volt
@...
-----Original Message-----
From: owner-bbc-micro@... [mailto:owner-bbc-micro@cloud9.co.uk]
Sent: 08 May 2001 20:59
To: bbc-micro@...
Subject: [BBC-Micro] 3.5" floppies and IDE hard-drives
Does anyone know whether it is possible to convert standard PC 3.5"
floppydrives and harddrives to be used with the BBC B or Master? If so, is
there any documentation I can get my paws on to have a bash?
Thanks