Frequency is defined as the number of cycles per second. It can also be defined as the reciprocal of the total time ‘T’. In this project, we will be counting the number of pulses entering into Port 3.5 of the 8051 microcontroller and displaying it on a 16×2 LCD display. Essentially, we are measuring the frequency of the signal at Port 3.5 of the 8051. For this purpose, we have used the AT89S52 8051 chip, and a 555 IC is utilized in Astable mode to generate the sample pulse for demonstration. It’s worth mentioning that we have previously built a Frequency counter using Arduino, further adding to our experience in this area.