Commodore VIC-20: changing the boot colour scheme
7How to customise your VIC's boot colour scheme from the default white background, cyan border and blue text to something of your choosing.
In my example I've gone for the Amstrad CPC464 colour scheme of blue/blue/yellow ... looks terrible ;)
The background & border setting can be found in the kernel ROM at offset 0xDF3:
.byte $1B ; screen and border colour (offset 0xDF3)
; bit function
; --- --------
; 7-4 background colour
; 3 inverted or normal mode
; 2-0 border colour
... and the text colour is at offset 0x550:
A906 LDA #$06 ; colour blue (offset 0x550)
The VIC chip's colour palette consists of:
Border/Character Colours:
00 = black, 01 = white, 02 = red, 03 = cyan, 04 = purple, 05 = green, 06 = blue, 07 = yellow
Aux/Background Colours:
00 = black, 01 = white, 02 = red, 03 = cyan, 04 = purple, 05 = green, 06 = blue, 07 = yellow, 08 = orange, 09 = light orange, 0A = pink, 0B = light cyan, 0C = light magenta, 0D = light green, OE = light blue, 0F = light yellow
23xx-to-27xxx ROM adaptor:
https://github.com/SukkoPera/Open2327RomAdapter
VIC-20 kernel ROM disassembly:
http://www.zimmers.net/anonftp/pub/cbm/src/vic20/index.html
Jay's Clearvideo for VIC-20:
https://www.etsy.com/au/listing/775553994/clearvideo-for-vic-20-rf-modulator
Mac OS Hex Editor:
For many years I've been using 0xED but unfortunately it just keeps crashing these days so I've just switched to Hex Fiend. I also use UltraEdit but it's had a longstanding bug with hex copy/pasting (I reported it many years ago, doesn't appear fixed yet) so I prefer to use a seperate hex editor.
https://hexfiend.com/
#commodore #vic20