Processor Technology -
VDM-1
This was the first practical teletype
like video board for the S-100 bus. It was later replaced by the better
Solid State Music board and later still by others that incorporated LSI chips on
the board along with a keyboard input connection.
While it worked it was not a clean PC
board layout. There was an "embarrassing" ribbon cable connection from one side
of the board to the other. Composite video came out via a connector at the top
left hand corner of the board.
The VDM-1 generated sixteen 64 character
lines from data stored in a 1024 8-bit byte on-card RAM memory.
Alphanumeric and control characters (the full 128 upper and lower case plus
control ASCII character set) were displayed in a 7 x 9 dot matrix. With
its EIA video output, the VDM-1 could be used with any standard video monitor.
(A TV set could be easily modified for use with the VDM-1).
Two-port memory permitted random
read-write access to the screen memory from the memory bus of the CPU.
Other features included:
-
Normal (white-on-black background)
video display or inverted (black-on-white background) video display,
switch-selectable for entire screen or program-controlled for each
character.
-
Video inversion block cursor,
switch-selectable blink capability, programmable for each character
location.
-
Continuously adjustable display
position, both vertical and horizontal.
-
Text blanking (switch selectable)
from CR control character to end of line and from VT control character to
end of screen, excluding CR or VT character.
The manual for this board can be
obtained
here
Other Processor Technology
S-100 Boards
4K RAM
8K RAM 48K
RAM
16K Dynamic RAM
1702
EPROM 3P+S
CUTS GPM
VDM-1
Helios-II FDC
This page was last modified
on
01/08/2011