| Re .0:
Here's one of those "obviously great" ideas that might not be
technically feasible. I have a cartridge port extension for my C=128
that can't support my RAM expansion unit because it's sensitive to
electrical noise.
Even if properly shielded, I wonder if Amiga bus timing is critical
enough that it would be unable to tolerate an extra few nanosecond
delay in talking with whatever is plugged in to the far end of the
extender. I don't know how fast the bus runs, but a 40" extender on an
8MHz bus would represent a phase lag in excess of 20� atop whatever
latencies exist in the other electronics.
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| Tom Senna has put together a 3 slot expansion board. He has one
installed on his 500, and I believe recently installed on on a 1000.
I have one of the boards and have sucessfully run a Hardframe,
ASDG Dual Ser Port board, and a 2052 mem board w/no problems.
I had been unable to run this configuration in other expansion
boxes (2 board limit), and most would barf with the ASDG Ser board.
It seems like Tom has a good product here. The expansion box sits
at the end of a couple cables, there is a transition connector that
plugs in to the 86 pin bus and two ribbon cables plug into that.
This assembly protrudes approximately an inch or so on the left.
Currently, I have about 15" of cable to allow positioning of the
expansion in an unobtrusive place on my desk.
Some benefits of the board are:
1. Requires it's own power supply (+5, +12, -12) so it does not
load down the A500 supply.
2. Has 3 2000 style slots vs the normal 2 slot expanders on
the market.
3. Has built-in bus termination which cleans up the signals.
4. Connects to the 500 through cables; flexible placement of the
expander box.
Needless to say, I am happy with the performance of the board. I
use my 500 at work and was looking for a way to expand it without
having to buy another 2000. Tom mentioned an add-on board which
would allow a processor/video slot to possibly be added, but you
should talk to Tom about this (HPSTEK::SENNA if I remember right).
No, this hasn't been a paid announcement... It just seemed this
might be what some 500 owners have been looking for...
As an aside, I have tested the expansion with a CLtd Kronos, CLtd
2000, Hardframe, Phoenix, ASDG Dual Ser Board, A2052 Mem, Micron
Mem (sensitive). All work ok (Micron is sensitive in the 2000 also)
John
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