Rumor has it that jpero_at_cgocable.net may have mentioned these words:
>> Anyone care to take a guess as to the difference?
>>
>> The 12887A has a "erase" pin on the package, so even if there are no
>> jumpers on the motherboard to erase the CMOS, you can jumper that pin to
>> ground for a few seconds and Voila! Wiped settings.
>
>To clarify that, that shorting withing futher steps do NOTHING. The
>usual practice is jumper it and toggle power for few seconds then
>power down and pull aside that jumper.
Survey Says: Bzzzt. Not the 12887A. Just jumpering the pin for a few
seconds is all it takes - no power cycles at all. You can clear the memory
when the motherboard is out of the case and hooked to nothing. [[o.k...
Make me get the PDFs...]]
Dangit... those PDFs almost drove me batty, until you get to the last page
of each... The pinout for both chips are exactly the same, with pin 21
being _RCLR_, or Active Low Ram Clear... but on the 12887 the last page
says this:
NOTE: PINS 2, 3, 16, 20, 21 AND 22 ARE MISSING BY DESIGN.
[[ the page held all caps - I'm not yelling, I'm quoting. ;-)]]
The 12887A chip says this on the last page:
NOTE: PINS 2, 3, 16, 20 AND 22 ARE MISSING BY DESIGN.
[[ the page held all caps - I'm not yelling, I'm quoting. ;-)]]
So, they gave the 12887 the ability to clear it's RAM, but they didn't
bother to put a darned pin there!!! Is that loopy, or what?
>12B887 is same thing too as 12887A far as I can tell.
Ah, maybe... I don't know about stuff newer than the A series, but while
downloading the PDFs, it seems theres a 12C887 available now. (BTW, there
is no PDF for a 12B887... maybe they're phased out already???)
Geezzzzz... a quick peek at that PDF shows that there is no _RCLR_ pin at
pin 21 anymore -- it shows No Connection. Boy doesn't that irritate me!!! :-(
Well, the PDF was listed as "Preliminary," so maybe they're still doing
revisions on the chip... Let's hope so.
Anywho, back to work...
"Merch"
--
Roger "Merch" Merchberger --- sysadmin, Iceberg Computers
Recycling is good, right??? Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.
Received on Tue Sep 28 1999 - 20:38:02 BST