What’s your opinion about digital clock? If you have deep interest on digital clock, then this project is perfectly well tailored for you!
This digital clock is slightly different than others, as it’s an Ultra High Accuracy Digital Clock For this project, a PIC16F873 is used as the main heart to control the input-output port. In order to make the circuit becoming even more compact, complex programmable logic device (CPLD) is also being used in this project. Since the building block of a CPLD is the macro cell, it won’t waste too much of space. Furthermore, the characteristic of non-volatility makes the CPLD the best device in modern designs, where it can be used to perform “bootloader” functions before handling over control to other devices that don’t have this capability!
There are two important things, where you have to pay attention in this project. Firstly, when the digital clock measuring counts time of 1 second, it can be delayed compared with the correct clock. For your information, 1 second is made by counting 20 miliseconds in 50 times, where it should be changed into 49 times!
Secondly, the blink interval of time setting must be changed from previous 500 milisceconds into 200 miliseconds interval, if you want to watch the display of the change time more accurately.