Hi, I need to design a simple frequency counter to measure the frequency of a square wave input (hence signal conditioning is not needed for now). I have understood the concept that the counter needs to count the input pulses for 1 second and display them on a 7-segment. My problem is how am i going to use the latch function (LE) to keep showing the frequency that was counted.

This is what I came up with so far:


The input signal (in this case 50Hz) triggers the 1Hz monostable, hence counts for 1 second. The problem is that after that 1 second, the counter resets to zero and recounts to 49 in this case. I need to find a way to keep the counter on 49 rather than going back to zero. Later I will add a 10Hz and 100Hz monostable for decimal points but for now I need to understand this concept.

Thank you.

 

You need to use the LE (latch enable) to read and store the data from the counters. You have them grounded. Then read and update the latch every new reading.

 

yes i know. the problem is that when i connect them, the counter marks 50, but then goes back to 0, then back to 50, then 0 etc...

 

Have you made a flow chart of the required sequence? After you figure out the sequence of what needs to happen you will be able to figure out how to make it happen.