Up/Down counter circuits needed

[dschwartz]

Hi all, i have been learning about logic circuits, and i´m thinking of designing a switcher/looper..
My design needs a counter like 4017, but able to go up and down with different switches (and up switch and a down switch). I´ve seen that 4029 IC may do the job, but i don´t quite understand the sample circuits, since they are used for binary counting, and it has a lot of inputs (Jam inputs?) that i simply dont understand... s

is there a simple circuit that can do something like this?:
press "up"--> out1 high
press "up"--> out2 high
press "down" --> out1 high
press "up"-->out2 high
press "up" 4 times--> out6 high

[alanlan]

3 to 8 line decoder should do the trick 

[dschwartz]

uhm.. i searched a lot about 3 to 8 decoder , and nothing about a counter..or even a sample circuit!..do you have an example?

[scratch]

I think what he meant to say, is take the output of a regular up/down counter, feed it to the inputs of the 3-to-8 line decoder ... should give
you a single line that responds to your count ...

[valdiorn]

Find yourself a good book on digital design. I read this for a college course:
Digital Design Fourth International Edition by M. Morris Mano and Michael D. Ciletti
It was good, expains everything you need to know to design a system like this by yourself.

Basically, if the counter doesn't have a "decrement" input you need to do some design work yourself. I would personally use two flip flops and then a summer and subtractor. A design like that might be a bit tricky to implement if you don't have experience. Do you know anything about programming microcontrollers, because with a PIC or AVR this would be extremely simple (program the chip in C to do your bidding, use one uController chip instead of 5-6x 7400 series chips ).

[mth5044]

R O Tiree will hopefully step in and be able to help you 

He drew up schematics at my request for an up down counter that went from 0-8 (or 1-9) with 7 digit display, and also flips through 9 combinations of  switches. I could post the schematics, but I think it might be more confusing  I dont know, hopefully he steps in 

[R.G.]

Don Lanaster's "CMOS Cookbook"

[R O Tiree]

Here's what I put together for mth5044.

Hopefully it'll make sense. The circuitry was done in Circuit Wizard Pro, which is just the bells and whistles version of LiveWire, which I know you have already, so you should just be able to copy this and play around with it.

What file extension does LiveWire use? Circuit Wizard uses "*.cwz" so, if LiveWire does the same, I could stick this circuit up in my webspace and you could download it directly istead of having to copy it. Let me know, Daniel?

And I endorse R.G.'s choice of book to get you started. Back in the day, I got into this stuff with the "TTL Cookbook" from the same series.

As I said to MV towards the end of the thread I linked to, µ-controllers are great, if you can afford the money to invest in the equipment, and time to learn how to program the chips. For a run of pedals, then this might be the way to go. However, for a one-off or a limited run, maybe not. Also, knowing how the logic works is essential to understanding, so messing about with individual CMOS chips is a very good place to start.

[dschwartz]

Thanks guys!!
It looks complicated! .. for something so simple!
About the book..well, i live in chile, and books are waaay expensive here.. i searched for free pdf´s books, and i couldn´t find it, but i downloaded "J.P.Uyemura_-_Cmos_Logic_Circuit_Design"..500 pages of cmos to learn..ufff..

R O, thanks for your input!, one question, the switches are momentary or latched?

[R O Tiree]

Both are Momentary SPDT. I explained why in my last post - S-R flip-flops, which de-bounce the switches.

If LiveWire uses *.cwz as a file extension for saved files, I can send you the original - let me know?

[dschwartz]

oh.. i think i have the version with .lvw extensions