8 Dec
2007
8 Dec
'07
4:44 p.m.
------------Original Message:
Date: Sat, 8 Dec 2007 18:30:43 +0000
From: Ethan Dicks <ethan.dicks at usap.gov>
Subject: Re: GAL16V8 as a modern substitute for a 7447?
On Sat, Dec 08, 2007 at 08:12:30AM -0800, Peter C. Wallace wrote:
On Sat, 8 Dec 2007, Ethan Dicks wrote:
Right.
Has anyone here worked with or ever plotted
silently to create a moderish
7-segment decoder/driver from a GAL16V8?
IICRC the 16V8 does not have buried registers so you will lose the 4 of the
output pins (for the counter) that you needed for the 7 segment outputs If you are using sockets, a 5V or 3.3V (cheaper) 44
pin PLCC CPLD might be
a better solution, plus they are easier to program. A X9572XL will probably
do 4 decades of count/decode for about $2.00
That is not feasible. I need 7 or 9 decades of count/decode, and I happen
to have an abundance of GALs and a GAL programmer. If it comes down to a
CPLD-design, I'll probably throw in the towel and use an AVR microcontroller
and perhaps a real 74LS47 or 74LS247 to lower the I/O requirements a touch.
I was just musing about what it might take to put it all in hardware
rather than a combination of hardware and firmware. Using an MCU makes
the entire problem trivial.
Thanks,
-ethan
-----------------
--------------Reply:
Well, since it started one of "those" discussions here as usual anyway,
what's wrong with a 74143?
mike