8080 Assembler-Text Editor (ATE)

Tony Duell ard at p850ug1.demon.co.uk
Tue Apr 18 17:09:21 CDT 2006


> What was more amusing was two different versions -- "with tails" and
> without!  :>

There's also the 'hooked 7' (segments a,b,c,f using the conventional 
names), used by some Japanese manufacturers. AFAIK no TTL decoder ever 
generated that one. 

In the mid 70's there were several circuits in the UK magazines to turn 7 
segment code back into BCD, so you could use clock/calculator/DVM chips 
with built-in display drivers in other logic circuits. Most of those 
encoder circuits, of course, made liveral use of the 'don't care states'. 
Some of said circuits would handle both tailed and tail-less 6's and 9's, 
but IIRC most of them failed on hooked 7's.


> 
> > That said, I think it is a pity there wasn't a later TTL 7 segment 
> > decoder chip (say a 74LS547 or something) that did display 0-F as you 
> > might expect. 
> 
> *Something* does this -- though I may have been driving LCD's

There was a Fairchild one, I forget the number.


> at the time (thus CMOS parts).  But, I remember a 7441 (though
> what I used it for I am unsure... :< )

1-of-10 decoder, commonly used to drive nixie tubes.

-tony



More information about the cctech mailing list