Uploaded May 2024 | Updated September 2026, 1 hour ago
This is a quick video to demonstrate my 80 column extension to the Cerberus 2100's video system.
By default, the system only supports a 40x30 text mode. I have rewritten the logic for the 2 video CPLDs to not only support a new 80x25 text mode, but also to enable switching resolution on the fly without having to reprogram the chips.
I have also added support to BBC BASIC for the new mode, including the addition of the MODE command to enable dynamic resolution switching.
At the BASIC prompt, typing "MODE 1" will select 80 column mode, and typing "MODE 0" will switch back to 40 column mode.
Other software can easily be extended to make use of graphics mode switching. Writing a value of 1 to 0xFFF9 will select 80 column mode, and writing a value of 0 will revert to 40 column mode.
If you want to try this out for yourself, all of the updated files are linked below...
Updates CPLD Files
github.com/movievertigo/CERBERUS2100/tree/main/CPLD_Files
Updated BIOS
github.com/movievertigo/CERBERUS2100/tree/main/CAT/CERBERUS_2100_BIOS
Updated BBC BASIC binary
github.com/movievertigo/CERBERUS2100/blob/main/Cerberus%20uSD%20card%20files/basicz80.bin
Updated BBC BASIC source code
github.com/movievertigo/CerberusBBCBasic/tree/main/bin/bbcbasic
Voice: elevenlabs.io
This is a quick video to demonstrate my 80 column extension to the Cerberus 2100's video system.
By default, the system only supports a 40x30 text mode. I have rewritten the logic for the 2 video CPLDs to not only support a new 80x25 text mode, but also to enable switching resolution on the fly without having to reprogram the chips.
I have also added support to BBC BASIC for the new mode, including the addition of the MODE command to enable dynamic resolution switching.
At the BASIC prompt, typing "MODE 1" will select 80 column mode, and typing "MODE 0" will switch back to 40 column mode.
Other software can easily be extended to make use of graphics mode switching. Writing a value of 1 to 0xFFF9 will select 80 column mode, and writing a value of 0 will revert to 40 column mode.
If you want to try this out for yourself, all of the updated files are linked below...
Updates CPLD Files
github.com/movievertigo/CERBERUS2100/tree/main/CPLD_Files
Updated BIOS
github.com/movievertigo/CERBERUS2100/tree/main/CAT/CERBERUS_2100_BIOS
Updated BBC BASIC binary
github.com/movievertigo/CERBERUS2100/blob/main/Cerberus%20uSD%20card%20files/basicz80.bin
Updated BBC BASIC source code
github.com/movievertigo/CerberusBBCBasic/tree/main/bin/bbcbasic
Voice: elevenlabs.io
