One Giant Pixel? Exploring $D020 and VIC-II/6510 Timing

The VIC-II video chip in the Commodore 64 has a control bit that will cause the screen border to cover the entire screen, filling the whole screen with whatever colour is currently in the border colour register, location 53280 or $D020. This sort of makes the entire screen one giant pixel, but of course it's much more complicated than that when you start considering constant dynamic interaction between the 6510 CPU and the VIC-II. There's actually a lot that can be done with just that one colour register, and when we start modifying it and counting CPU cycles, we can learn a lot about how the system works. Links: http://www.atarihq.com/danb/files/64doc.txt https://8bitshowandtell.com/downloads/border.d64 To support 8-Bit Show And Tell: Become a patron: https://patreon.com/8BitShowAndTell One-time donation: https://paypal.me/8BitShowAndTell 2nd channel: https://youtube.com/channel/UCAgWzEh5c8391eJnELDy9OA Index: 0:00 Playing around with the border 1:03 One giant pixel? 5:10 border1 on NTSC C64 (breadbin) 8:13 border1 on NTSC 64C (HMOS VIC-II) 11:26 INC $D020: a close-up analysis on NTSC C64 19:37 INC $D020 on PAL Swedish C64 23:07 src2 on NTSC C64: stable bars 28:50 src2 on NTSC 64C: grey pixel 31:47 Preliminary Stable raster? 37:18 Thanks!