The microprocessor and a large support chip sit on either side of the top of
the prism. They are in a complicated flex circuit that fold around the
interior of the body. The processor is a 4-bit one with its program in a 4k
word ROM.
This is the fundamental difference between the early OMs, through 1N and 2N,
and the later ones, the 3s 4s and 2sp (which is not at all like the 2 or
2N). The early ones are marvels of compact electromechanical engineering,
with all sorts of little springs, levers, strings on pulleys, meter
movements. There are a few simple circuit boards. The later microprocessor
models simply emulate most of that in software. The sensor and control
inputs are digitized and sent as input to the computer, which then sequences
the various actions of the camera. They may have a traditional user
interface, except for the averaging spot meter, but they are pure
wunderbrick inside. Wunderbricks without bells and whistles.
Repairmen can always make a new spring, gear, or cam. They cannot fabricate
computers and flex circuits. As the flex circuits die (probably the LCDs
will go first), they will be replaced. 2sp circuits have all been gone for
several years. When the stock of circuits is gone, the cameras will not be
repairable. In 30 years or so, there probably will hardly be a single
working 4T on the planet, but probably tens of thousands of 1s, 2s, 10s,
meterless 3s, Trip 35s, RCs, etc.
Paul
At 02:19 PM 2/18/00 -0800, you wrote:
>Well it certainly has something like a microprocessor. It must have an ALU
>(Arithmetic Logic Unit), memory, LCD driver and timing and control circuitry
>at a minimum. A custom IC would probably have been more economical that
>off-the-shelf for this application. But such a chip would definitely fall
>under the term 'microprocessor'.
>
>george
>
>
>-----Original Message-----
>From: Dirk Wright <wright@xxxxxxxxxxxx>
>To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
>Date: Friday, February 18, 2000 12:11 PM
>Subject: Re: [OM] Re: macro posts please
>
>
>>>On my examples, at least, I find that the 2N has a greater usable
>>range
>>>for TTL flash than the 4T. It will handle closer distances and wider
>>>apertures by about 1 stop or so. This means its TTL system is faster
>>>reacting. This may be due to using analog electronics for TTL shutoff
>>>rather than emulating then with a digital computer.
>>>
>>
>>I really doubt that the 4T has a microprocessor in it. I could be wrong
>>of course.
>>
>>
>>Be seeing you.
>>
>>
>>Dirk Wright
>>
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>>
>>
>
>
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