BI-80 Display Adapter

  • While the Commodore 64’s 40-column screen was a vast improvement over the 22-column screen of the VIC-20, it was not optimal for word processing or terminal applications where 80-columns is standard. Prior to the Commodore 128, which includes a crisp RGBI 80-column screen, cartridges were produced to add hardware 80-column display to the Commodore 64.

    The BI-80 cartridge from Batteries Included adds 80-column video in hardware using the 6545. Interestingly, it also includes an expansion ROM that adds BASIC 4.0 commands.

    Software Control

    BI-80 can toggle between 40- and 80-column modes under software control. On power up, the 40-column screen is active. To switch to 80-columns, use SYS 33000. To return to 40-columns, use SYS 33003.

    The BASIC 4.0 extension can also be controlled in software. On power up, the extension is active. Use SYS 33009 to disable it and SYS 33006 to enable it again.


    SYS-ROM – 2732 (4K) EPROM for “SYS-ROM” socket (yellow label; firmware)
    CHR-ROM – 2732 (4K) EPROM for “CHR-ROM” socket (red label; character ROM)


    Owner’s Manual – PDF format
    Character Set – Rendered to an image by Steve Gray