P
Phil Hobbs
Guest
On 11/5/20 1:49 PM, Don Y wrote:
Don L talks about doing that in the CMOS Cookbook, iirc. The next most
general way he gave to implement a truth table directly was data
selector logic. I once did the logic for a hot-spare system in a satcom
central station with a CD4067B.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
On 11/5/2020 11:22 AM, Edward Rawde wrote:
I\'ve seen people use expensive chips when a diode and resistor would have
been fine.
But then I was introduced to logic gates as diodes, resistors and the
occasional transistor if an inverter was needed.
A fellow I worked with designed a graphic LCD interface. As he was unsure
of the exact logic required to derive a few of the control signals, he
installed an *EPROM* to act as a crude PLA. This let him release the
board to manufacturing while he tinkered with the contents of the EPROM.
I looked at the functionality that it was effectively providing. It
(and the time to PROGRAM it!) could be replaced by a quad NAND and hex
inverter.
shakes head
Don L talks about doing that in the CMOS Cookbook, iirc. The next most
general way he gave to implement a truth table directly was data
selector logic. I once did the logic for a hot-spare system in a satcom
central station with a CD4067B.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com