By | September 3, 2017
Digital Clock by using seven segment displayWe used 6 GAL IC in our project, first 2 IC’s are for minutes and last two IC’s are for hours.

GAL 1 is programmed in a manner that it counts from 0 to 9 and then resets by generating a carry at pin 21.


This carry goes to the clock pin of GAL 2 which counts from 0 to 5 on each pulse provided by GAL 1.

All GAL IC’s (GAL number 2 to 4) change their state whenever they pick a carry the previous IC’s EXCEPT GAL number 1.

When the direction input (dir) is held at ground, GAL cpunts from 0 to 9 normally. But when ‘dir’ is connected to ‘fc’ (force stop carry) it only counts from 0 to 5 and resets by generating a carry.

The last 2 IC’s are for hour purpose and they are dependent on each other.
Digital Clock by using seven segment displayIf last IC is displaying 0 then GAL 5 counts from 0 to 9, but if the last IC (GAL 6) is displaying 1 GAL 5 counts from 1 to 2 only. (This is because my clock is a 12 hour clock only so 1 to 9 is illegal.

So I connected the carry of last IC with ‘dir’ of GAL 5 and developed this logic. 
A switch is provided from Vcc t0 carry pin 1 of each GAL, so carry can be provided from Vcc to adjust time yourself. High at pin changes 1 state of GAL IC.
For the clock, I used 555 timers with f = 1 Hz at GAL 1. 

Schematic Diagram: 
Learn How to Make Digital Clock by using GAL MIcrocontroller


This Project is Made by Waqar Ahmed Wajahat Ali M.Shahruk Department of Applied Physics Karachi University

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About Abid Jamal

Abid Jamal Received his B.S. Degree in Electronics & Communication in 2014 (Gold Medalist) from University of Lahore, Islamabad, Pakistan and Master’s Degree in Electrical Engineering from Capital University of science and technology, Islamabad, Pakistan, in 2016. He is the Creator of www.Electronicslovers.com website. Awarded by “A” grade in Electronic & circuits MIT online certificate. He achieved an academic Excellence certificate in the year 2014. He received Dean Honor Roll award for earning GPA 3.67, Spring-2015 in MSEE. He has done many projects using Different kinds of microcontroller. His research interests include Radar Cross Section measurements, Smart Grid communications, Intelligent transportation systems, driver-less car, cellular mobile communication & networks, improve Smartphone’s battery life for 3G+LTE user’s, and embedded systems.

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