Editing Commodore Plus/4 (section)

=== Graphics ===

The [[MOS Technology TED|TED]] offered 121-color (15 colors × 8 [[Luma (video)|luminance]] levels + black) video, a [[Palette (computing)|palette]] matched only by the [[Atari 8-bit computers]] and the [[Enterprise (computer)|Enterprise]] at the time, and 320×200 video resolution, similar to many computers intended to be capable of connecting to a television.

The TED chip had identical resolutions and video modes to the [[MOS Technology VIC-II|VIC-II]] (bitmap or character graphics which could be high-resolution or multicolor), but lacked hardware [[Sprite (computer graphics)|sprites]]. Its sound capability was a two-voice [[Square wave (waveform)|square wave]] generator.

The first eight colors of the TED's palette are the same as the VIC-II, but colors 8-15 are different. It allowed each color except 0 (black) to be set to one of eight possible luminance levels, thus making 121 total colors possible.

The power-on default configuration places the screen memory at {{mono|$0C00}} and the color memory at {{mono|$0800}}. Color memory is integrated into the TED and there is no separate color RAM like on the VIC-20 and C64. Bits 0-3 of each byte in color RAM hold the color value and 4-6 hold the luminance. Bit 7 is a [[Flag (programming)|flag]] that sets blinking text. [[Bitmap]] mode is similar to the C64, however in hi-res mode the color RAM is used to supply the luminance values for each block (bits 0-3 the luminance for color 0 and 4-7 the luminance for color 1) while it is not used at all in C64 hi-res graphics. In multicolor bitmap mode, the same setup is used, but while on the C64, color RAM holds the values for color 3, on the Plus/4 it instead holds the luminance values for colors 1–2. Color 3 is instead global and obtained from the register at {{mono|$FF16}}.

The Plus/4's TED has several advantages over C64's VIC+SID. All TED [[Hardware register|registers]] that are available can be read and written. TED may realize the blinking cursor and the characters in the reverse-video mode. It may display 256 characters in the text mode. It may use graphics split by [[raster interrupt]] and show pictures at 320x288 resolution.<ref>{{cite web|url=http://plus4world.powweb.com/software/40x36c|title=The examples of Plus/4 graphics}}</ref> This, with [[Interlaced video|interlaced]] mode, makes it possible to show 320x496 images. In addition, the TED has 16 [[address line]]s, thus it can "see" the entire memory space of the computer unlike the VIC-II. The video buffers may thus be placed anywhere in memory and there are no mirrors of the character ROM to get in the way like on the C64.<ref>{{cite web|url=http://www.lemon64.com/forum/viewtopic.php?t=47356|title=The examples of Plus/4 graphics|date=8 April 2013 }}</ref>