In this article we implement virtual (computer simulation base) microcontroller driven programmable timer using Proteus VSM. This proposed system is design using Microchip PIC16F877A – 8bit microcontroller and its system software is developed using MikroC PRO 3.2 for PIC. Most of the components in this proposed design are based on Proteus VSM - simulation models and we assign standard component names to them to assist in actual prototyping.
In this simulation we use PIC16F877A as main system controller and 4 row monochrome LCD display unit with HD44780 compliant controller (in 4bit mode). This proposed simulation model is design to work with +5V supply voltage, but it can also operate using battery power (3 × 1.5V).
When implementing this system for the real-life use, it is highly recommended to integrate battery backup facility to this system. It helps to drive this system continuously with minimum amount of disturbances.
According to the supplied source code, end user may be able to program start time and end time of the timer or specify only the start time. Once the timer get started user may be able to terminate the timer by pressing “OK/Timer Disable” key.
Please note that this system is provided only for demonstration purposes and end user need to calibrate MCU crystal and other associated components to obtain exact 1Hz clock trigger. The Lamp (L1) shown in the simulation model is for the demonstration purposes only. Ignore this component at the prototyping stages. All the source codes and Proteus ISIS simulation files of this project is available to download at elect.wikispaces.com.