Counting TTL Input signals
 

Hi,

I need to write a counter code to count the number of spikes in the TTL logic input signal... What should I take as an input... Can i write it normally by putting the count in an infinite loop like

while(1)
// increment count

exit(1)

something like this... or is there a different way of doing this.

J

Re: Counting TTL Input signals
 

What has your instructor or teacher advised you to do? Do you have any notes.

Re: Counting TTL Input signals
 

I don't have any notes. I am free to do what i please. But I was just baffled about how to program the whole thing.

Suppose a pulse generator gives out signals as a stream and we need to count the numberr of pulses... then how do we do that.

Re: Counting TTL Input signals
 

I would suppose it depends on how the pulse generator is sending the signals -- out its RS232 serial port ? If that is the case you will have to attach an rs232 serial cable to your com1 or com2 port and listen for incoming data on the computer side. Most likely it will be just a change in state of one of the pins instead of incoming data. Its been over 10 years since the last time I have done that so I would have to research some very old code, if I still have it, to see how that is done. One thing for certain, you will need a 16-bit compiler such as Turbo C that will allow direct access to ports. You might also need to do a little assembly language.

Re: Counting TTL Input signals
 

Are you actually capturing data from this device? or is it a make-believe example where you have to simulate the data capture?

simulating data capture should be easy - just read some data of your choice from the keyboard, and process it bit by bit as the pulses are read (the usual choice for representing digital input such as electromagnetic pulses is 1 and 0, but you could use anything)

A loop would be useful for determining when data capture is finished. You could use selection (eg - if/else) to determine whether the input is "on" or "off".

If there is a real device which you're reading from, then it still may be a good idea to start your program with simulated keyboard input where you are controlling the input - this means you can get that part right before you attempt to combine it with your real data capture code.

Re: Counting TTL Input signals
 

I am simulating the input using the Pulse Generator. The actual input will be from some other source. When I fix the pulse generator the computer has to start counting the number of pulses. How do I do this? Firstlyy the system has to detect the start of the pulse and then it has to count until the stream is stopped. The number of pulses has to be given as the output. What is a way to doing this. Can this be done usng a count program or is there any other way?

Re: Counting TTL Input signals
 

how is the pulse generator connected to the computer?

Re: Counting TTL Input signals
 

using an RS 485 cable i think

Re: Counting TTL Input signals
 

is the pulse generator going to actually send data to the computer or just change the state of one of its 32 pins to on and off ?

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Re: Counting TTL Input signals
 

TTl signals will be amplified and sent to the computer and it would have to count them. We are not connecting the source of signals just yet and will be testing it using a pulse generator to test the code.... how do i write a code to count the number of pulses issued?