Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Simplest VGA tester on PIC

There are still lots of displays with VGA around us. So when repairing or testing them VGA tester become a handy tool. Technikservice suggests using a simple PIC based VGA tester that require very few parts including PIC microcontroller, 4MHz crystal, cap and potentiometer. Of course a VGA connector is also required. Design is based on Eric Schlaepfer scheme that generates VGA signal in 640×468 mode at 60Hz refresh rate. Circuit simply emits a “TEST” text message on screen which is enough for simple checking. Continue reading

Simple PIC VGA tester

While searching for information on how Chris invested some time and developed a simple VGA tester on PIC18F452 microcontroller. Device is capable to output simple figures and text to VGA monitor. It is possible to select one of RGB colors one at the time with simple switch. Circuit of VGA tester is very simple because VGA signal is a digital signal, no additional circuitry is needed. As timing on generation of VGA signals is essential, there is external 4MHz crystal used, and all programming is done in low level assembly language. Microcontroller clock speed is slow, only 26x480px resolution can be generated. Possible improvements as author says are: resolution increase by increasing clock speed and color intensity regulation with DAC. But lets be simple – it is perfect VGA monitor tester that fits in to the pocket. Continue reading