Commodore PC 20 - Page 45

o
o
Video
RAM
Custom
VlSIVldeo
Timing
Generator
Video Circuitry
Figure D-I
I-----H----Light Pen Connector
L.::..t--f-ll-- Output for
RF Modulator
'-----I----1 ..... --Composite
o
Video Output
Video Output
Connector
ATI Graphics Solution Block Diagram
0.2 Getting Started
The video default mode is the video mode that your computer will
automatically
power up to when you turn it on. Three video default
modes exist. Emulation mode runs Commodore PC Color / Graphics
or Plantronics Enhanced Graphics software on a Commodore
monochrome monitor or equivalent. Monochrome Graphics mode
runs PC or Hercules compatible monochrome graphics software on
a monochrome monitor. Color/Graphics mode runs PC Color /
Graphics
or Plantronics Enhanced Graphics software on an RGB or
composite monitor. Before you plug in your monitor you must
determine the video default mode you require relevant to your
application. The eight DIP switches on the ATI card control the
mode of the video adapter (see Figure D- 2). Switch positions 5 and
6
on the main circuit board control the default mode of the
computer itself. (See Table D-l.) Descriptions of video modes are
found in Section D.4.2.
WARNING
Your ATI Graphics Solution has been factory preset to
the Mono mode. If you intend to use your AT! Graphics
Solution
on an RGB color monitor, or on a composite
color or monochrome monitor, you must change your
video default to the Color/Graphics mode (see Figure
D- 2). Otherwise, damage could result to your monitor
that is not covered by warranty, because of the higher
horizontal scan
rate in monochrome mode.
Using ATI 29