hp proprietary uP history (9825 uP?)

From: Joe R. <rigdonj_at_cfl.rr.com>
Date: Tue May 4 19:13:10 2004

At 12:17 AM 5/5/04 +0100, you wrote:
>> >Incidentally, the 9845 has one bit of bad design, IMHO. It's not trivial
>> I agree that it could have been better. The 9845s are very unreliable.
>> I'm having to constantly reove, clean and reseat the cards in order to keep
>> them working.
>They shouldn't be any worse than any other HP machine unless they've been
>stored badly and the connectors have not been properly cleaned. They use
>much the same edge conenctors as everything else.

  That's what you'd think but it isn't the case. 9825s in paricular are
nearly indestrucable but I have constant problems with all of the 9845s.

>> >All the clocks have the connector and logic for the external interface,
>> >it's just a cable you have to add.
>> IIRC the main circuit board has a connector but IIRC you have to add the
>> mating connector along with the cable. However I've been lucky and found a
>Yes. You get the pin header on the PCB (with a loopback test connector
>normally). You have to remove that loopback conenctor and plug in the
>cable. It's a standard 0.1" pitch header, so the mating connector is
>trivial to find.
>> fair number of modules with the cables already installed. However I think
>None of mine came with cables, but that was soon cured :-)
>[The watch chip ans the microcontroller]
>> That's interesting. I hadn't looked that close at the workings of the
>> time module and had no idea that it was built that way. I wonder why it
>> included all of that?
>Prsumably they needed the functionallity of the microcontroller when the
>machine was powered up for things like triggering external events,
>responding to the inputs, etc. But the micorcontroller, ROM, etc took too
>much power to be battery-backed so they had to add a lower-power clock
>for when the machine was turend off. A watch chip, suitably repackaged
>(it's in a 24 pin DIP IIRC) was the obvious choice at the time.
>> >electrolyte less so (but they can generally be repaired). 16 bit parallel
>> >interfaces are really common, but the versions with particular I/O
>> >cables, other thnn the Option 085 one for the 8" floppy are much rarer. I
>> >am still looking for wire- and jumper- lists for all the optional cables.
>> So am I. I think I have one or two of them but that's all.
>If you have anything apart from the user-terminated one and the 085
>floppy one, can you buzz out the connections and note down which links
>are fitted, please. I assume you have the 98032 user manual which
>explains the connections and links.

  I'll look and see what i have. IIRC I used to have one that was modified
for a PT Punch.


Received on Tue May 04 2004 - 19:13:10 BST

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