6845 Alpha Numeric Video Card: Revision A

Last Updated: November 09, 2005 09:48:34 PM


REV. A of the card the 6845 card. The top RCA connector is for composite video, the 9 pin connector provide video, horizontal drive, vertical drive for an Electrohome monitor. This card replaces System-4 video card. This card is based on a design that appeared in BYTE Magazine May 1979.


Issues/todo log

Date Description Status
Remove Divide 6 or 7 dot clock jumper
Add lower case character set
Remove divide by character clock 7490 and jumpers
Fix schematic 74163 and remove jumpers
Add DB9 pin connector to PCB
A11 Pin 21 of EPROM should be tied low not high Fixed via double socket Rev. A

Schematics, board layout, and operational description

Revision Production Date Schematic Layout Operational Description Font EPROM
A Feb. 15/2005 v6845-a.sch v6845-a.brd TBD


B In development *untested* v6845-b.sch v6845-b.brd