Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Help me understand Counters

Status
Not open for further replies.

Vicountboo

Newbie level 5
Joined
Dec 11, 2003
Messages
9
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
104
Counters

Hello
I need some help in understanding about Counters.
-What are they all about
-Why do we use it and
-When do you know you need to use a 12 bit or 8 bit counter instead of a 4 bit counter?
Thanks for help.
 

WA

Member level 4
Joined
Mar 27, 2002
Messages
72
Helped
6
Reputation
12
Reaction score
2
Trophy points
1,288
Location
wherever I go - there I am!
Activity points
948
Re: Counters

A counter is a time-based and a counter based application.

What I mean is that it's used to syncronize other circuits.
For example, If I want one gate to turn on after another gate, I can use a counter.
The counter starts at zero. and (usually binary) begins counting up 1,2,3...
So lets say gate 1 activated and sent output to another gate. I could set an and-gate in circuit and tie one input to count 3.
Now this circuit will not allow anything through until the counter is at three.

Counters can be used as time delays, clock circuits (for telling time) etc...

As for the size of counter (4,8,12 bits)? This depends on how high you want your counter to count.
4- bit = 0-15
8- bit = 0-255
12- bit = 0-4095
As you can see, The more bits, the higher your counter can count. It is up to the designer to see how high a count they need.
The rule of thumb for counters is that they are in powers of 2
ex. 2^x where x is any positive number.
So 2^2 = 4, 2^3 = 8, 2^4 = 16 etc...

I hope this helps somewhat.
wa
 

papyaki

Advanced Member level 2
Joined
Apr 13, 2002
Messages
539
Helped
38
Reputation
76
Reaction score
18
Trophy points
1,298
Location
France
Activity points
5,346
Re: Counters

Hi,

I think this tutorial about counters can be helpfull :

h**p://www.eelab.usyd.edu.au/digital_tutorial/part2/counter01.html

* = t
 

Kevin Weddle

Advanced Member level 4
Joined
Jul 10, 2004
Messages
101
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Location
San Antonio, TX
Activity points
1,220
Re: Counters

I have had an experience with a BCD counter. I wanted to use a counter fed to a decoder. But the BCD counter has 0 - 15 outputs. I think they should call it a counter decoder.
 

ipcore

Member level 2
Joined
Aug 4, 2001
Messages
42
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
200
Counters

based on the time interival you need 2^n
 

jay_ec_engg

Full Member level 3
Joined
Jun 19, 2004
Messages
155
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,296
Location
India
Activity points
1,581
Re: Counters

no. of bits used to design counter depends on ur application... like if u want counting upto4 u need 2 bits.. if u want 256 then 8 bit.. and accordingly.....
generaly counters are used to count incoming data... like frames.... samples.... etc..... or u can say to find the time interval.... say ur clokc is of 10Mhz( 100ns) and u want to count for 300ns..( 3 counts)...... like that... for what purpose u need counters ??
 

adi-niunio

Newbie level 3
Joined
Jul 11, 2004
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
28
Re: Counters

Kevin Weddle said:
I have had an experience with a BCD counter. I wanted to use a counter fed to a decoder. But the BCD counter has 0 - 15 outputs. I think they should call it a counter decoder.


Are you sure that your BCD counter has 0 - 15 outputs. I think that BCD counter has 4 data outputs, and it counts only 0,2,3,4,5,6,7,8,9 in binary cod. (like UCY7490).

0 -15 outputs has a "1 of 15 counter" or 4bit demultiplexer.
 

Kevin Weddle

Advanced Member level 4
Joined
Jul 10, 2004
Messages
101
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Location
San Antonio, TX
Activity points
1,220
Re: Counters

No, it has 0 - 15 outputs. This makes it a counter decoder don't you think?
 

WA

Member level 4
Joined
Mar 27, 2002
Messages
72
Helped
6
Reputation
12
Reaction score
2
Trophy points
1,288
Location
wherever I go - there I am!
Activity points
948
Re: Counters

The BCD has 4 inputs.
Because there are 4 input, there must be 15 outputs.

Since the primary use of BCD is numerical use. the remaining outputs are not used. The outputs (BCD 0-9) is just that. But BCD outputs (10-15) are patterns (like small h etc) are generally not used.

As the designer/implementer, it is up to me to use these or not. If I don't need (or want), then I must ensure the conditions don't exist for these unwanted outputs.

hope this helps in understanding BCD's
wa
 

Kevin Weddle

Advanced Member level 4
Joined
Jul 10, 2004
Messages
101
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Location
San Antonio, TX
Activity points
1,220
Re: Counters

BCD normally means the count goes from 0 to 9. That is correct. The count is 0 to 9 with a binary output representative of the the number of pulses. So you should have 4 output lines that only count 0 to 9 and start over. However, this was not the case.
 

Serg_SV

Member level 3
Joined
Jun 30, 2004
Messages
66
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
429
Counters

You must take book about digital schematic and boleava algebra
 

ozek

Newbie level 5
Joined
Nov 14, 2003
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
21
Re: Counters

Hi,
look at Digital design
Morris MANO
 

starfish

Member level 2
Joined
Jul 8, 2004
Messages
53
Helped
7
Reputation
14
Reaction score
6
Trophy points
1,288
Activity points
564
Re: Counters

Counters are used in many applications.................

They basically count the clock pulses supplied to them..........

Can be used for timing control of some circuitry............

4bit , 8 bit , 12 bit etc counter length depends on ur application......

a 4 bit counter can max count from 0-3
a 8 bit counter can max count from 0-255

In general a counter of n bits can count from 0 to (2^n-1) :):)
 

mopengfei

Member level 1
Joined
Aug 10, 2004
Messages
41
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
hangzhou of china
Activity points
280
Counters

this is true that the counter of n bits can count any number from 0 to (2^n-1),it is very useful i
 

lambtron

Full Member level 5
Joined
Nov 2, 2005
Messages
251
Helped
34
Reputation
68
Reaction score
8
Trophy points
1,298
Location
Portland, OR
Activity points
3,546
Re: Counters

And now for something completely different: some counters are bidirectional, meaning that they can count up AND down. This is done by having a combination of inputs instead of just a single clock. For example, such counter might have both Clock and Direction inputs to control up/down counting.

This is very useful for applications in which the physical position of something is to be monitored with an incremental encoder. This is a device with TWO output clocks that are 90° out of phase with each other (i.e., "quadrature" encoded). An incremental encoder can be connected to a quadrature counter. The counter will count up when the encoder turns clockwise and down when the encoder turns counterclockwise. The physical position can move arbitrarily back and forth all day long and, at the end of the day, the counter will correctly indicate the position.
 

neils_arm_strong

Full Member level 5
Joined
Jan 5, 2006
Messages
289
Helped
22
Reputation
44
Reaction score
3
Trophy points
1,298
Location
Bangalore, India
Activity points
3,247
Counters

counters are used for counting,time delays etc.The no of bits of the counter depends on the maximum count that is required.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top