12 Sep
2001
12 Sep
'01
9:46 a.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
Oops. Sure is.
Hmm... good point. I do recall seeing some stuff about how wierd the
addressing normally is (something about the progression for multiple
cards going like 0x03ee, 0x04ee, 0x05ee, then something like 0x3e1...
I don't recall the actual numbers off the top of my head.) I don't
have an ISA spec in front of me - is there an A13 and A14 on an 8-bit
slot?
That sounds a
little like what I have... Mine are National Instruments
180212-01, Rev A PCBs (c. 1984), silk-screened to Assy. No. 180210-0.
The main chip is an NEC 7201, the IEEE-488 interface chips are Nat.
Semi
I'll bet that's a typo for 7210. There's a
five-position DIP switch labelled "0, 1, 2, 14, 13", which I
take to be a GPIB address, a bank of jumpers marked
I wonder if that might be part of the I/O address. Lines 0,1,2 and 13,14.
IIRC, the IBM GPIB card did decode address lines other than the normal 10
used by most I/O devices. The top ones were used to select between
multiple GPIB cards in the same machine IIRC. That last set might be 'Request' and
'Acknowldge' for DMA? In other words
a DMA channel select.
Right.
> indicating that it could have a Lithium coin
cell, a 58167...
The 58167 is a real time clock IIRC. In which case the
Xtal is almost
certainly a 32.768kHz one. They normally come in a tiny cylindrical can.
The silk-screen shows an oval spot with the leads spaced about .2" apart.
I expect that it was for one of those flush-mount .1" tall Xtal cans.
The small cylindrical ones I've seen on motherboards could be made to
fit with no problem.
You can probably raid the 58167 off an old XT real
time clock card, or
some older AT motherboards, or the like.
Good point. Did AT motherboards have them? I've mostly seen Dallas
chips with embedded batteries on clone boards.
The other passives aren't that critical. The
values of the capacitors
connected to the crystal (around 22pF) you can get from the 58167 data
sheet. Try 10k for any pull-up resistors and 0.1uF ceramic for decoupling
capacitors. That should be a start.
Good tip.
Now the problem is what kind of software support there is for these. One
thing I might do (eventually) is to cobble up a driver for the GG2 Bus+
for the Amiga *if* DMA is optional. If DMA is required, it's a no-go.
-ethan
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