i need a decade counter, like the 4017 for example, wich can count to any umber from 4 to 16 best will be 8, but it doesnt matter. i need it to have 2 input pins, so that if i aply pulses to one pin it will count up, and pulses to the other input pin it will count down. the reason why i can not use a counter wich has a pin for clock and one for select between up or down is that the i have 2 bit that control the counter cannot be 1 in the same time...
if i think better i could use a binary counter too....
anybody can help me?

 

Bogdan

I don't know if it is still in production but the 74192 (74LS192 etc) is an up/down decade counter.

Pin 5 counts up and pin 4 counts down. BCD preset if you want it.

It is a bcd output - IIRC - so you would need a bcd to decimal decoder OR, if you want to drive a 7seg led then 74ls192>74ls75>74ls47>led.

I used to use these to build up/down Hz/KHz counters for hf receivers with analogue displays. Made it much easier to get accurate tuning.

I haven't got the datasheets but they should be available.

 

A Cmos chip will do.......CD4510, its a 4bit binary up down counter, use it in conjunction with a suitable counter chip wil get your counts up to 16......

HTH Chip

 

yes, i know the 74192 and 193 but they are hard to find here and quite expensive, so i have an idea.
if i could take the 2 bits and use a flip flop with set and reset so that one bit sets it so i have Q=h wich will count up and in the same time the bit is sent to the clock input of a 4029. when the other bit is H then i have a reset and i got Q=L so it will count down
here is what i mean, do you think it function?
or i will need some delay so that first it is set wich direction it will count and then it will get the pulse?i cant upload here so i will up load to electronics ideas.....

 

For using flip flops have a read of this...

http://www.usna.edu/Users/ee/cameron...alCounters.pdf

A light and entertaining read if nothing else.

And Page 13 of...

http://web.mit.edu/16.070/www/year2001/com.pdf

 

here is what i think of.....

Attached Images

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it looks like i am talking alone here, but, can i use a CD40193 for what i need?

 

Hi Bogdan,

No, you're not alone. Jobs that pay - and celebrations - have to come first.

The circuit will work if you tie the S & R inputs to gnd via a suitable resistor.

If you look at the truth table for the 4013 you will notice that pin 1 is the opposite of the R input and that pin 2 is the same. This would allow you to control count direction with one bit.

If the 40193 is similar to the 40192 - no datasheet handy - then it should be ok.

 

Umm likewise,work n stuff......I did suggest some alternatives, probably easier to work with too.....

 

And don't forget pull-down the diodes common cathode....

 

Pilot,
i am not sure i understand _ what you want to suggest?
i know i can conect Din to Q and create a toggle flip flop, so i have one bit for the clock and one for the direction.....
i think that this will work too, but it will be a bit harder to control what i want trough software.....
i dont need to put the resistors from R ans S to Gnd because when the bits are not 1 they are 0 not opened, so i dont see the need for these resistors...
Sebi, i really dont get what diodes are you talking about....

 

we also just did that assignment,try to use 7490 or 74190 :idea:

 

The CLK pin never goes to low without pull-down resistor...

 

yep you are right.
i forgot that i put the diodes there.....