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Path: utzoo!watmath!clyde!amd70!phil
From: phil@amd70.UUCP (Phil Ngai)
Newsgroups: net.micro
Subject: clocked FF from PAL16L8
Message-ID: <4577@amd70.UUCP>
Date: Fri, 4-May-84 02:58:56 EST
Article-I.D.: amd70.4577
Posted: Fri May  4 02:58:56 1984
Date-Received: Sat, 28-Apr-84 10:50:45 EST
Organization: AMD, Santa Clara, CA
Lines: 21

Something I've always sort of wanted was a way to implement a edge triggered
flip flop using a PAL16L8 type of device. Since the 16L8 only has an AND-OR
structure in it (no clocked FF like the 16R8) this seems to many people to
be impossible to implement.

Well, I just did it, I think. I am wondering if this is new and novel enough
that people are interested in hearing about it, or if it is just old hat
to experienced circuit designers. (how about PAL hackers?)

Why would you want to do this? If the choice is to use an external FF and you
have to operate on the signal before putting it into the FF, you don't have
to spend the two pins getting out of your PAL and into the FF. You also save
all the extra pins on the FF that you never need like Q* or even worse,
RESET and SET which you have to pull up. (plus you don't need to stock
external FFs or read data sheets :-) [anyone ever get the pinout on a 7474
wrong?]) If the choice is to use a 16R8, sometimes you want several
different clocks, while the 16R8 restricts you to one clock per package.

	BURN MORE PALS!
-- 
Phil Ngai (408) 988-7777 {ucbvax,decwrl,ihnp4,allegra,intelca}!amd70!phil