2 Digit up/down Counter using PIC16F628A

This project comes via two circuits on 2 boards. The first circuit is designed around a PIC16F628A. It has been presented on an experimental PC board using surface-mount components and was built in less than 1 hour, with about 2 hours to write and finalise the program. SeeΒ  P1,Β  Β P2
The second circuit uses a PIC12F629 to produce a 2-Digit Up/Down Counter (see P3).
Both use β€œIn Circuit Programming” via PICkit-2.
P5
Describes the up/down counter displaying the β€œgear” for motorcycles and racing cars.

2 Digit up or down COUNTER

The project shows what can be done with a micro and you can modify it to set an alarm at any count-value or set a limit such as β€œcount-to-60.” You can add a buzzer or relay or increase the display to 3 digits. You need to remember that each additional display will reduce the illumination of each digit as they are β€œmultiplexed (time-sharing).”

The experimenter PC Board shows the five β€œIn Circuit Programming” pins and a diode on the positive rail to drop the 6v supply to 5.4v. The board also has a 100n surface mount capacitor and two surface-mount transistors. The Up/Down buttons have 22k resistors. TESTING THE CIRCUIT
Check the circuit by removing the chip and taking pins 6 and 18 to the 5v rail
ad make sure segment β€œA” illuminates. Do the same for all the other segments.
The circuit diagram does not have any voltages marked on it as the circuit is DIGITAL.
All the β€œlines” or β€œwires” or pins of a microcontroller will have rail voltage (5v) on them when they are HIGH and when you come to a resistor, the resistor will drop a certain voltage. The voltage it will drop will be the difference between rail voltage and the voltage developed across the component it is driving. If it is driving a LED, the LED will drop a characteristic voltage of between 1.7v and 3.6v, depending on the colour.
If the component is a transistor, the voltage developed between the base and emitter will be about 0.7v.

 

For more detail: 2 Digit up/down Counter using PIC16F628A


About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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