# Yet another 74LS191 Counter Thread

#### MemT

Joined Mar 1, 2013
6
hello i am working in this project of using a standar counter up/down so the thing is thats i am not using buttons insted i am using some part i took from a old radio and i make this:

Turn right go "Down", Turn left go "Up" easy right ? then i said "oh ok, i can make a counter from 0 to 77 (octal) or 6 bits using two 74LS191 and make this:

so then cascading using only one "i dont know how is called thiny" i can turn and make a easy 0 to 77 counter and 77 to 0 but they are 65 combination it will take to much time incrementing a unit at time.

So using two "i dont know how is called thiny", one for the units and the other for "tens" capable of going "up" and "down" like normal i come to this using livewire.

and when i turn one the other cant work, so ok all is woking but how could i make with less ic ? and well only using TTL LS ic and well what you guys think about my project ?

#### MrChips

Joined Oct 2, 2009
21,663
If you can explain it succinctly in twenty words or fewer maybe we can help you.

#### MemT

Joined Mar 1, 2013
6
so far making an up/down counter with one control for the first digit and one control for the secound digit, the control that active firts will prevent the other to work this mean only one control can be used at time, and the counters are cascading.

I manage to do all this, but with to many IC, i need help to reduce it, and i cant find a example with this counter in cascanding going in up and down, like counting 0 to 99 and 99 to 0

( sorry i could go with fewer words )

#### MrChips

Joined Oct 2, 2009
21,663
Are you trying to:

Design a 2-digit 00-99 up/down counter.

11 words.

#### WBahn

Joined Mar 31, 2012
26,063
How about something like this (will be more than 20 words):

A 2-digit up/down counter with two controls. One increments/decrements 1 unit at a time and the other 10 units at a time.

It also appears that you want it so that you can't use one if the other is in use. Why is that important. Just only use one at a time.

Here is an idea. use a switch or a momentary push-button to change the mode from count-by-1 to count-by-ten. Then you don't have to worry about blocking the other control because you only have on control.

#### MemT

Joined Mar 1, 2013
6
#4: 2 digit 00 to 77 up/down counter , cascading the up and down.

#5 it was becouse i belive one unit at time will be to slow, so i try it to see how fast will be and it well i was wrong, the speed was good enough

and so Schematics

#### WBahn

Joined Mar 31, 2012
26,063
It sounds like you have it working satisfactorily, so congrats.

My question wasn't why you wanted two modes (x1 and x10), but why you felt the need to disable one control when the other was in use.