a classiccmp electronics project?

From: Joe R. <rigdonj_at_cfl.rr.com>
Date: Sun Aug 1 09:49:33 2004

At 10:35 PM 7/31/04 -0500, you wrote:
>Joe wrote...
>> Bob Shannon has ordered these and gotten them so I'm wondering why all
>> the sudden interest in using EPROMs or SRAMs. But I thought I'd let the
>> discussion continue and see what developes. From what Bob told me he
>> orders one specific part but Jameco sends him several different brands.
>> They're supposed to be equivilent but apparently that's only in read mode.
>> They are programmed differently and he's had both good and bad luck
>> programming them.
>It was Bob that told me he had pretty pitiful luck with finding ones, and
>the ones he did find had a very low success rate.

   I think the reason that Bob has had such little success is due to the
fact that his programmer only has one setting for the 256 x 4 PROMs and it
tries to program all of them the same way. If you look at the settings used
in in a Data I/O 29, Stag or Prolog programmer you'll see that the
different brand parts are programmed with different settings. I think
you'd have MUCH better success programming the parts with those
programmers. I have a pamplet from Pro-Log that describes PROMs and EPROMs
and it list the different types of technology and materials used in the
PROMs. They are VERY different from each other. EPROMs are pretty standard
but PROMs aren't.

 Hence, the discussion of
>> >> There's no room for a duaghterboard to mount on the HP 1000 card.

>I beg to differ.

  ??? On my 1000s the board with the PROMs is located in the bottom of the
chassis and UNDER an aluminium plate with just enough room for the parts on
the board to clear the plate. In fact, there are holes in the plate to
allow access to the PROMs without having to remove the board from the
bottom of the machine. The holes aren't very big, perhaps 1 1/2 x 2 inches
so I doubt you could build a dautherboard small enough to fit inside of one.


 But one could always run a short and heavily shielded cable
>to it.
Received on Sun Aug 01 2004 - 09:49:33 BST

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