In practice, it often happens that it is necessary to repair, inspect or set VGA monitor and a personal computer no. In this case, there are some uncomplicated generator VGA video signal on the PIC16F84 microcontroller PIC16C84 or. Scheme the device was developed by Eric Schlaepfer (Eric Schlaepfer) and widely circulated on the Internet. Unfortunately, there is an error (incorrect the number of the power supply pin of the microcontroller), and the attached "firmware" is for CGA/MDA monitors, and VGA monitors are not working.
Offer the revised scheme (see figure) and the program (codes firmware shown in the table), adapted for VGA mode 640x480 at 60 Hz.
Source code
(click to enlarge)
Powering the device is possible from any source of voltage of 4.5 To 5 V, including from a battery of three cells or four Ni-Cd batteries.
When the slider of the variable resistor R1 is set to the extreme left position and turn the power on first monitor, and then the generator. Slowly reducing the resistivity of the entered part of the resistor, making the appearance on the screen major label "TEST". To set a higher brightness image not recommended.
Author: Yuri Lysenkov, Kramatorsk, Donetsk region, Ukraine