16 to 4 line encoder

[danuke]

does anyone know of a 16 to 4 line encoder and part number? It can be either cmos or ttl. I've searched google and here and didn't come up with anything. If something exists like this please let me know.

All help is appreciated.

Thanks,
Joe

 

[blueroomelectronics]

Never seen such a chip. Wonder how would it handle more than one high input at a time?

 

[danuke]

Never seen such a chip. Wonder how would it handle more than one high input at a time?

Not sure on the more than a single high part. Basically looking for something like a BCD encoder or a 10 to 4. I'm actually just looking at using 12 of the inputs, not all 16.

 

[Pommie]

Have a look at the 74148 - 8 to 3 priority encoder. If I remember correctly there is some way to cascade them.

Alternatively, it can be done with a diode array. Tie each output low and have a diode from each input to each output line that has to be high.

Mike.
Edit, google priority encoders.

 

[nickelflippr]

Harris HD0165

 

[ericgibbs]

does anyone know of a 16 to 4 line encoder and part number? It can be either cmos or ttl. I've searched google and here and didn't come up with anything. If something exists like this please let me know.

All help is appreciated.

Thanks,
Joe

hi,
Look at the HEF 4532 , 8 input priority encoder, you cascade two of these ic's to give a 16 bit encoder.

 

[on1aag]

Hi Danuke,

Here's one, but that chip is almost as old as I am.

https://www.alldatasheet.com/datasheet-pdf/pdf/53736/FAIRCHILD/74C922.html

You gonna have to "visit" a museum to get one.

on1aag.

 

[ericgibbs]

Hi Danuke,

Here's one, but that chip is almost as old as I am.

https://www.alldatasheet.com/datasheet-pdf/pdf/53736/FAIRCHILD/74C922.html

You gonna have to "visit" a museum to get one.

on1aag.

hi on1aag,
You must visit my workshop [museum] , I have got about 4 or 5 on the shelf!

Actually they are 4*4 [x,y] scan matrix to a 4bit output with a strobe, used on keypads.

 

[Nigel Goodwin]

That's what the 74C922 was, a keypad encoder.

Perhaps the OP might like to mention what he wants it for?.

 

[blueroomelectronics]

I've seen the 74C922 on the University of Toronto PIC demo board. You can still get them but they cost more than a PIC 16F628A would (that could replace it, and offer more features too like key rollover and buffering) and enough I/O left over for a buzzer

 

[ericgibbs]

I've seen the 74C922 on the University of Toronto PIC demo board. You can still get them but they cost more than a PIC 16F628A would (that could replace it, and offer more features too like key rollover and buffering) and enough I/O left over for a buzzer

hi Bill,
I would agree they are expensive, I wouldn't recommend them for a new design.
However, I have seen 2 or 3 members asking for information on the ic.

 

[Nigel Goodwin]

However, I have seen 2 or 3 members asking for information on the ic.

I suspect it's mainly because they look in the old databooks, or google for keypad encoder, and this is what pops up.

 

[ericgibbs]

I suspect it's mainly because they look in the old databooks, or google for keypad encoder, and this is what pops up.

The members asking the questions have also been in the 'developing' countries, I wonder if its the 'time shift' factor on obsolete components?

Actually, the 74C922 is/was an excellent device, its just the price thats counts it out, never had one fail!

There are lots of posts ref 741 opa, I expect the hedgerows of the world are littered with 'old' devices.

 

[Leftyretro]

The members asking the questions have also been in the 'developing' countries, I wonder if its the 'time shift' factor on obsolete components?

Actually, the 74C922 is/was an excellent device, its just the price thats counts it out, never had one fail!

There are lots of posts ref 741 opa, I expect the hedgerows of the world are littered with 'old' devices.

It reminds me of the robust business on E-bay for Nixie tube displays. Seems that many want to build digital clocks using these old displays even though it's really old tech and can take quite a few bucks gathering all the high voltage parts and such. I use to have tons of that old stuff around but somehow between home moves most is gone. Still have lots of mid 80s and on stuff.

Lefty

 

[danuke]

That's what the 74C922 was, a keypad encoder.

Perhaps the OP might like to mention what he wants it for?.

I'm using it to encode 12 pushbuttons into a 4 bit code. It's not for a keypad per say but something similar. It's just going to take the 12 pushbuttons and make it into a 4 bit binary value so that it can be used with less traces to be run, etc on a pcb.

 

[Nigel Goodwin]

Obvious method would be to use a PIC to do it, and either run four traces as planned, or even one as a simple serial interface. You've not mentioned what the rest of the project is?, but it's probably also simpler to replace the rest of it with the same simple PIC? - or a couple of them?.

 

[danuke]

I really don't have any experience in PIC work. I've been thinking about diving into that world, but really don't know what type of programmer chips etc would be a good starter kit.

I pretty much know when I get into that, I'd want to use flash based PICs for learning on so I can play around without spending several dollars per chip. If you happen to know of an easy programmer to learn on, please feel free to recommend one. I'd like to try to stay under $50 for a whole kit (1 flash chip, programming hardware, and software) if possible.

 

[Nigel Goodwin]

Check out the InchWorm, an ICD2 clone - cheap and VERY capable.

 

[danuke]

does the inchworm+ come with the components and circuit board or just the circuit board?

 

[blueroomelectronics]

If you're using USB then I'd recommend a Junebug, the kits come with all the parts.

Since dipmicro does not carry the Junebug I'll see what I can arrange with Creatron Inc (they have stock both kit and assembled)