SmartPort low-level details?

[Roger Johnstone]

I've been thinking about building some sort of drive for the Apple IIc
using the disk port, like the old IIc hard drives, but using flash RAM.
I have the Apple IIc Technical Reference Manual but it only covers the
SmartPort firmware interface. There's info available on the Internet
covering the IWM at the register level for people writing drivers for it,
but nothing on the actual electrical signals that the IWM uses to
communicate with the other devices on the bus. I know the UniDisk 3.5
used an IWM too, but what about the third-party hard drives? Were they
all IWM to IWM interfaces?

I can try and reverse engineer the signalling protocol using the (rather
simple) logic analyser at work, but if there's any documentation
available it would be a LOT easier.

[Glenn Jones]

Post by Roger Johnstone
I've been thinking about building some sort of drive for the Apple IIc
using the disk port, like the old IIc hard drives, but using flash RAM.
I have the Apple IIc Technical Reference Manual but it only covers the
SmartPort firmware interface. There's info available on the Internet
covering the IWM at the register level for people writing drivers for it,
but nothing on the actual electrical signals that the IWM uses to
communicate with the other devices on the bus. I know the UniDisk 3.5
used an IWM too, but what about the third-party hard drives? Were they
all IWM to IWM interfaces?
I can try and reverse engineer the signalling protocol using the (rather
simple) logic analyser at work, but if there's any documentation
available it would be a LOT easier.
--
Roger Johnstone, Invercargill, New Zealand
PS/2 Mouse Adapter for vintage Apple II or Mac
order at http://vintageware.orcon.net.nz

Roger ... Do you have the IIgs Hardware ref manual... I thought the hardware
interface between the IIc(+?) and IIgs were very similar.

I could be mistaken...

Glenn

[Roger Johnstone]

Post by Glenn Jones

Post by Roger Johnstone
I can try and reverse engineer the signalling protocol using the (
rather simple) logic analyser at work, but if there's any
documentation available it would be a LOT easier.

Roger ... Do you have the IIgs Hardware ref manual... I thought the
hardware interface between the IIc(+?) and IIgs were very similar.
I could be mistaken...
Glenn

You could be right. They are basically the same port since they're both
driven by the IWM chip. About the only info I've found so far has been
the comments in the IIc ROM listing which mention a BUSY and a REQUEST
line, and the tech note SmartPort #8 <http://web.pdx.edu/~heiss/
technotes/smpt/tn.smpt.8.html>, which refers to each byte in a packet
taking 32 microseconds. This ties in, since the IWM sends a single bit
in 4us for 5.25" disks. It can run at 2us for 3.5" disks, but doesn't
use it for intelligent drives since the fast speed can only be used on a
IIgs.

Can anyone with the Apple IIgs Hardware Reference tell me if it has any
information on the communication the IWM uses? Not the firmware or
register-level operation, but the actual signalling used i.e. which
drive port pins are used for busy, request, clock, data or whatever the
lines are called! I suspect it will use the four motor phase pins.

[Bill Garber]

Post by Roger Johnstone

Post by Glenn Jones

Post by Roger Johnstone
I can try and reverse engineer the signalling protocol using the (
rather simple) logic analyser at work, but if there's any
documentation available it would be a LOT easier.

Roger ... Do you have the IIgs Hardware ref manual... I thought the
hardware interface between the IIc(+?) and IIgs were very similar.
I could be mistaken...
Glenn

You could be right. They are basically the same port since they're both
driven by the IWM chip. About the only info I've found so far has been
the comments in the IIc ROM listing which mention a BUSY and a REQUEST
line, and the tech note SmartPort #8 <http://web.pdx.edu/~heiss/
technotes/smpt/tn.smpt.8.html>, which refers to each byte in a packet
taking 32 microseconds. This ties in, since the IWM sends a single bit
in 4us for 5.25" disks. It can run at 2us for 3.5" disks, but doesn't
use it for intelligent drives since the fast speed can only be used on a
IIgs.
Can anyone with the Apple IIgs Hardware Reference tell me if it has any
information on the communication the IWM uses? Not the firmware or
register-level operation, but the actual signalling used i.e. which
drive port pins are used for busy, request, clock, data or whatever the
lines are called! I suspect it will use the four motor phase pins.

The IIc+ and the IIgs smartports are, I'd like to say identical, but
am afraid of Scott Alfter, so I'll say they are very close. The IIc
smartport is similar only it can only operate a UniDisk 3.5 drive,
but I believe that is due to it's firmware and speed only. If you
could add a larger rom, you probably could add romware and
put in a faster CPU then you might be able to operate a dumb
Apple 3.5 drive in them also.

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - ***@comcast.net



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[Glenn Jones]

Post by Roger Johnstone

Post by Glenn Jones

Post by Roger Johnstone
I can try and reverse engineer the signalling protocol using the (
rather simple) logic analyser at work, but if there's any
documentation available it would be a LOT easier.

Roger ... Do you have the IIgs Hardware ref manual... I thought the
hardware interface between the IIc(+?) and IIgs were very similar.
I could be mistaken...
Glenn

You could be right. They are basically the same port since they're both
driven by the IWM chip. About the only info I've found so far has been
the comments in the IIc ROM listing which mention a BUSY and a REQUEST
line, and the tech note SmartPort #8 <http://web.pdx.edu/~heiss/
technotes/smpt/tn.smpt.8.html>, which refers to each byte in a packet
taking 32 microseconds. This ties in, since the IWM sends a single bit
in 4us for 5.25" disks. It can run at 2us for 3.5" disks, but doesn't
use it for intelligent drives since the fast speed can only be used on a
IIgs.
Can anyone with the Apple IIgs Hardware Reference tell me if it has any
information on the communication the IWM uses? Not the firmware or
register-level operation, but the actual signalling used i.e. which
drive port pins are used for busy, request, clock, data or whatever the
lines are called! I suspect it will use the four motor phase pins.
--
Roger Johnstone, Invercargill, New Zealand
PS/2 Mouse Adapter for vintage Apple II or Mac
order at http://vintageware.orcon.net.nz

Searching google leads one to believe that the best source of information on
the disk II operation is Jim Sather's books. I don't have a copy but I will
take a look through some old user group magazines to see if I can find
anything for you.

From what I have gather so far, the actual signal operation of the interface
card to the drive hasn't changed (much) since Woz designed it. I am
surprised it hasn't been thoroughly disected by now.

You might want to contact Bill Martens of call A.P.P.L.E, he may have a way
of easily searching through back issues of that magazine for good technical
info.

Glenn

[Roger Johnstone]

Post by Glenn Jones
Searching google leads one to believe that the best source of
information on the disk II operation is Jim Sather's books. I don't
have a copy but I will take a look through some old user group
magazines to see if I can find anything for you.
From what I have gather so far, the actual signal operation of the
interface card to the drive hasn't changed (much) since Woz designed
it. I am surprised it hasn't been thoroughly disected by now.

It's compatible, but it was extended with the IWM chip. The 5.25" drives
work just the same as they did when Woz designed the original Disk II
controller, and 3.5" drives aren't much different. But Apple also added
the SmartPort packet protocol (see David Empson's post) which allows a
computer to communicate with intelligent drives. This works completely
differently from the way the non-intelligent drives work but was
cleverly implemented so all three types of drives can be daisy-chained
from the same port. It turns out that Apple documented the protocol in
the IIgs Firmware Reference, which is fortunate since Jim Sather never
wrote an 'Understanding the Apple IIgs'!

[Roger Johnstone]

Function PH3 PH2 PH1 PH0
Enable 1 x 1 REQ (handshake output)
Reset 0 1 0 1
It uses the "write protect" signal from the drive as an ACK handshake
line.
The drive select line is not activated (so 5.25" drives do nothing,
and ignore the strange combinations of phase signals).
If you can't find an online copy of the relevant section, I'd be happy
to photocopy that part of the IIgs firwmare reference and post it to
you. (E-Mail me with your address detais.)

Thanks David. Someone else has offered to send me that section of the
reference already, but if he has any problems I'll get back to you.

I'm sure not long ago I saw mention of a program like Apple's ProDOS
Exerciser, but for SmartPort calls. At the time I had no use for it and
now can't remember what it was called. Does anyone know the program, or
am I misremembering?

[Roger Johnstone]

Post by Roger Johnstone
I'm sure not long ago I saw mention of a program like Apple's ProDOS
Exerciser, but for SmartPort calls. At the time I had no use for it
and now can't remember what it was called. Does anyone know the
program, or am I misremembering?

I seem to recall that A2 Central had a program which let you play
around with SmartPort calls, possibly aimed at the Apple SCSI cards,
but it was generic enough to work with any card which supported the
SmartPort firmware interface.

I have all my old A2-Central disks on a single disk image for use with
Bernie and had already searched for any filenames containing SmartPort
but found none. I just had another look, searching by content this time,
and found a reference to SmartPort.Play, described as a SmartPort Peeker,
in the "Last time in A2-Central-on-disk" section of the March 1993
newsletter. The strange thing is I don't have the February 1993 disk,
disk image or physical, yet I had a subscription during this period and
have the disks before and after it. <sigh>

Some time later... OK, I found The SmartPort Commander at <ftp://apple2.
caltech.edu/pub/apple2/8bit/patches/smartport.shk> which looks like the
program we were both originally thinking of. Originally written by Tom (
Weishaar?) and appearing in Open-Apple.