All that talk of the Falcon VGA adapter modification got me thinking about BlowUP
so I thought I'd track down Georg Acher, the guy who made it ... and guess what ...
You have luck
I've made the sources now available. You can download them
under http://wwwbode.cs.tum.edu/~acher/blowup ... ources.tgz
They were developed with Pure-C. They contain a lot of german comments (some
of them really nonsense
, but they should be understandable with a little
Regarding the hardware: The Hard 1 was a simple 50MHz quarz oscillator
feeding the pixel clock input. The only trick was a resistor from the clock
signal to ground (depends on the oscillator, about 120 to 220 ohms, if its
wrong you see white or black streaks).
The Hard 2 had a variable pixel clock (33-55MHz), but contained no "real"
PLL. It was a VCO (NE564), its control voltage was generated by a CMOS
sample and hold circuit (CD4007) and a large foil capacitor. The paddle port
provided the up/down control of the voltage. There was a continous software
feedback loop measuring the vertical blank frequency and adjusting the
voltage accordingly. Sounds like an ugly hack, was ugly, but worked quite
The only trick was to stabilize the 5V from the Falcon, which was
done by a TL497 switch converter and a 78L05 linear regulator.
Georg Acher, firstname.lastname@example.org
"Oh no, not again !" The bowl of petunias
Now wasn't that nice of him!?
Maybe someone wants do draw up the schematics of the hardware!?