[sdiy] moog module designs

[Scott Gravenhorst]

Thanks again, I looked at their data sheet, the internal schematic isn't
even close to the Philips sheet.  The ST Micro abortion has a J-K input
circuit that cannot possibly ever consider the logic state of both J and K
inputs being high.  A bit of reading of the text from ST shows that they
consider this thing a D flop equivalent (they even mention 4013), (And in
fact any REAL JK flip flop can be wired as a D), so why not just use a
real D flip flop?  They seem to have specifically designed this to NOT
toggle as a normal JK can.  Since this was deliberate, Tim's mistake was
not in abusing the device with static shocks, rather it was buying from ST
Micro...  Umm, my condolences, and hopes you didn't buy many.

NOTE: Avoid whatever their engineers were/are smoking...

-- Scott (who doesn't have ST Micro 4027 ICs and is damned happy)

Neil Johnson <neil.johnson97 at ntlworld.com> wrote:
>Hi,
>
>Scott Gravenhorst wrote:
>> Thank you, Tim.  I guess it's something to be aware of.  I went to 
>> their
>> site and tried to look up 4027, but it doesn't seem to be there.
>
>The HCF4027 is on the ST website:
>
>	http://www.st.com/stonline/books/ascii/docs/2039.htm
>
>> Interesting that they didn't have the "J and K high" condition in their
>> truth table.
>
>In a way they do --- the 'X' refers to "don't care"... so the lines
>
>J	K	Q 	-> 	Q	Q'
>H	X	L		H	L
>X	H	H		L	H
>
>say exactly what happens for J = K = high, i.e., it toggles.
>
>> So here's a chicken and egg thing: Did they create the
>> truth table (incorrectly) and then get engineers to design this or did
>> they muff the design and then publish a truth table that shows the 
>> chip's
>> implementation?  Either way, that's pretty brain dead.
>
>Either way, the truth table is correct (for a J-K flip-flop).  As for 
>the implementation...
>
>Perhaps the chips in question are faulty?  One zap from an ungrounded 
>finger can kill a CMOS chip.
>
>Cheers,
>Neil
>
>--
>Neil Johnson <http://www.njohnson.co.uk>
>

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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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