Hi, how can I make an 8 bit counter using two 4 bit counters (ready made chip).

 

1. Any preference for IC's? TTL? CMOS?
2. Operating voltage?
3. Synchronous? Asynchronous?

Is this school work?

 

We can’t... unless you supply much more information. What’s a 2 two 4 counter? Do you have a part number? Is this school work?

 

We can’t... unless you supply much more information. What’s a 2 two 4 counter? Do you have a part number? Is this school work?

Hi,
I don't mind if it is synchronous or asynchronous. But I want to buy a basic 4 bit counter which doesn't have an output pin for a carry.... and make it into an 8bit counter

 

All counters have carry output. You just need to know where to look for it.
Which 4-bit counter do you have in mind?

 

All counters have carry output. You just need to know where to look for it.
Which 4-bit counter do you have in mind?

Hi
I was looking at the 74393 chip it doesn't have a carry output but it has two 4bit counters.

 

QD is your carry out.
Take QD output of the first stage and feed that into CLK of the second stage.

 

QD is your carry out.
Take QD output of the first stage and feed that into CLK of the second stage.

Thank you

I don't understand how this will make it work as an 8bit counter

Qd will output this 0000000011111111
but how will this make the other counter start counting.

 

I don't understand how this will make it work as an 8bit counter

By cascading them.

You haven't answered my question regarding whether this is school work.

 

That is how you can build an asynchronous counter using flip-flops.

The output of the 1st flip-flop goes 01010101010...
The output of the 2nd flip-flop goes 00110011001100...
The output of the 3nd flip-flop goes 00001111000011110000...
The output of the 4th flip-flop goes 000000001111111100000000...
and so on.

You can add as many flip-flops as you want to create an n-bit counter.

 

Thank you

I don't understand how this will make it work as an 8bit counter

Qd will output this 0000000011111111
but how will this make the other counter start counting.

Have you studied the datasheet! Here it is...

The counter advances by 1 every time the clock transitions from high to low. The output Qd does this when the four bit counter goes beyond 16 or the counter overflows.

By conducting Qd to the second clock, the second counter wil increment once for every time the first counter overflows. Qd will transition from high to low when the first four bit counter receives 17 clock pulses.

Is this school work?

Moderators: has anyone considered a presumptive classification of homework, when the TS dodges the question twice or more?

 

By cascading them.

You haven't answered my question regarding whether this is school work.

Hi thank you.
I'm working on a small project at home but I didn't want to buy an 8 bit so I asked about using 4bit counters.

 

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I'm working on a small project at home but I didn't want to buy an 8 bit so I asked about using 4bit counters.

I take it that you're trying to say this isn't homework?? Yes or no would have sufficed.

Just connect the D output from the first counter to the input of the second. Clear is HIGH active, so tie it LOW.

From TI's databook:

 

The second main problem that will probably keep you busy until you have a working S9V: Does it have a decent power supply?