40 and 80 column boards
Introduction to 40 and 80 column boards for the VIC-20
The VIC-20 was popular but suffered stigma among "serious" computer users (i.e. programmers & researchers) because of its 22-column display, which they felt was too limiting. To remedy this several third party companies released display boards which plugged into the VIC-20's expansion port, thereby giving it the ability to display 40 or 80 columns of text at once.
- Vendor: MSD, Inc.
- Software: 4 KB terminal program (40 column screen)
Video Pak Data 20
Includes 16K, needs extra power supply.
Display Manager Data 20 / Protecto 80 Cartridge
This cartridge takes over the video functions of the VIC, and allows the display of 40 or 80 columns B+W, using its own DIN port.
The VIC chip is still functional, so it is possible to setup a dual monitor system. Regular POKE statements can be used to update the original VIC chip screen.
This cartridge has space for expansion memory (U3-U6), which is populated in the Data-20 8K units.
$9BF8 CRT Controller HD6845 / control register $9BF9 CRT Controller HD6845 / data register $9BFC Mode Register Bit 0: Character set. 0 - upper case, 1 - lower case Bit 5: 40/80 Columns. 0 - 40 Columns, 1 - 80 Columns $A000-$A7FF BIOS ROM sys 40969 - 40 column mode sys 40972 - 80 column mode sys 40975 - return to vic 22 column screen sys 40978 - restart 40 or 80 column mode without clearing screen contents $B800-$BFFF Video RAM
F1 shift F2 unshift F3 Erase to end of line F4 Erase to end of screen F6 Screen dump F8 Terminal mode