AIM-65 displays

From: Richard Erlacher <>
Date: Wed Apr 17 20:24:58 2002

There are some similarities, though there are also some significant
differences. The KIM, IIRC, used address lines as chip selects more than the
AIM did. In fact, I don't believe (schematic is in my lap) I don't think the
AIM did that at all. The result of this practice is waste of memory space,
due to framentation and redundant decoding is at the heart of that. The AIM
uses decoders to select the peripherals and that makes for a cleaner

Now, I designed a DRAM board and FDC for the KIM-1 at one time, though I never
used 'em, not being a KIM-owner myself. The SYM seemed also to use address
lines for chip selects, so I didn't spend time with it either. They all had
the same bus pinout, IIRC. I don't think any of them had full-function debug
monitors. By that I mean something with the ability to (1) examine, move, and
modify memory map content, (2) read from some outside source in block mode,
(3) save to some outside destination device in some block mode, (4) perform
line-by-line assembly, and (5) perform line-by-line disassembly,
(6)single-step through code and (7) set/clear breakpoints when running code.
There are lots of other features, but if you keep the MSDOS DEBUG program in
mind, that's the sort of thing that MOTOROLA, for example, provided for nearly
all their processors.

The AIM has a resident debugger of some sort, plus and assembler and a basic
rom. I'm not convinced that anyone ever produced an OS of any sort
specifically for it, but the APEX OS was hacked to run on the KIM/SYM/and AIM.
The AIM version was probably the cleanest, but I don't know anyone who has it
any longer.

The differences, aside from device addresses, between the resident monitors
for these three systems that share a common bus, will be in their display
handler, their cassette handler, and the fact the AIM has not only the TTY
handler that both the KIM and SYM have, but a built-in printer as well, which,
though not the greatest, is WAY better than trying to remember what the code

If you skip over the I/O there's not a lot to these monitors. If you have a
decent display of some sort, and it's arguable that a 4x20 or evne 4x16 might
be adequate, you can probably run a pretty decent debugger provided you can
sufficiently expand your memory.

There were several easy hacks to the AIM board that relied on the presence of
additional memory on daughterboards or on expansion boards that were marketed
by several third party vendors. It's pretty easy to max out the memory
nowadays by putting a daugheterboard on the CPU socket and enabling a block of
RAM on it by the absence of chip selects to other I/O and memory on the AIM
board. The same, of course, works for the other boards.

If you want memory or FDC schematics, I can probably find them.


----- Original Message -----
From: "blacklord" <>
To: <>
Sent: Wednesday, April 17, 2002 6:08 PM
Subject: Re: AIM-65 displays

> Hi Dick,
> > I'll have a look to see whether I have any ROM listings. I
> > thought I did,
> > but, well ... they say the mind's the second thing to go ... can't
> > rememberthe first ...
> >
> The AIM is pretty similar to the KIM-1 no ? (I may be mistaken) The
> KIM's ROM dissasembly is pretty freely available, I have a version that
> was suppied with a text file on how to build your own using current
> chips.
> Made a half hearted start at it, but currently it's gathering dust :-)
> cheers,
> Lance
> ----------------
> Powered by
Received on Wed Apr 17 2002 - 20:24:58 BST

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