Hex to Seven-Segment Decoder

[abell118]

Ok, I tried to be helpful. The stuff on the web stays on the web. I guess it is time to bail on this site

 

[JimB]

I am sorry if you feel like that, the error which you initially pointed out was simply a "typo" I guess.

There must be many other similar errors here on ETO, I may have made a few of them.

I guess it is time to bail on this site

If you are not interested in staying around here, that is OK, there are many other sites out there on the interwebs.

JimB

 

[Ian Rogers]

Ok, I tried to be helpful. The stuff on the web stays on the web. I guess it is time to bail on this site

Much appreciated... We do like people that will help out.... You are more than welcome..... But the guy who started this thread, hasn't been seen since....

 

[shokjok]

use an EPROM/EEPROM/...

I suggest using an 8223 PROM and scratch-build a programmer, if you can locate this device. I cannot foresee the circuit being built with the logic devices that you are designing with.

 

[Steve Howard]

Well, it's June 2017 and I'm REALLY REALLY late to this. It's 10 years since the original post and 2 years since the most recent.

So, I'm here only because I was reminiscing about a project of this sort I completed in 1980. Google landed me here.

That design required a four-digit hex display, another 4-digit hex display, and a 2-digit hex display.
The standard BCD-to-7-segment decoder chip of that era only handled BCD values from 0 to 9.
I needed full hex, including A b C d E F. The decoder chip for that cost $10 ... or around $40 in today's money.
Too much for me, a recent grad working his first job.

So I did this with a 74154 decoder (takes a 4-bit value and turns on just one of the 16 available outputs) ...
... and a big, hand-wired diode matrix (with 77 diodes IIRC), wired to take the 1-of-16 active outputs from the 74154 and translate it to the appropriate seven segment outputs.

Signal diodes in those days were cheap ... around a buck for a package of 20 from Radio Shack. And the 74LS154 was cheap, too.

If I had back then a ROM programmer I could have used a UV erasable ROM and programmed it for the purpose. I think the common 2 K x 8 ROMs of that era cost around $5, making for a nice, single-chip solution.

 

[schmitt trigger]

This is what I call an "Lost Civilization" thread. I actually find them fascinating.

It usually happens when a lazy student wants someone else to actually do his/her course assignment.
When that individual does not receive a 100% solved problem, the thread is abandoned.
And is resurrected later by Google or another search engine.

Mind you, this is not unique to ETO.