Motorola 6847

The chip outputs a NTSC compatible progressive scan signal composed of one field of 262 lines 60 times per second.

According to the MC6847 datasheet,[7] colors are formed by the combination of three signals: ${\displaystyle Y}$ luminance, ${\displaystyle \phi A}$ chroma and ${\displaystyle \phi B}$ chroma, according to the YPbPr color space. These signals can drive a TV directly, or be used with a NTSC modulator (Motorola MC1372) for RF output.

${\displaystyle Y}$ may assume one of these voltages: "Black" = 0.72V; "White Low" = 0.65V; "White Medium" = 0.54V; "White High" = 0.42V.

${\displaystyle \phi A}$ (or ${\displaystyle R-Y}$) and ${\displaystyle \phi B}$ (or ${\displaystyle B-Y}$) may be: "Output Low" = 1.0V; "R" = 1.5V; "Input High" = 2.0V.

The following table shows the signal values used:[7][8]

Color	${\displaystyle Y}$	${\displaystyle \phi A}$	${\displaystyle \phi B}$
Green	0.54	1.0	1.0
Yellow	0.42	1.0	1.5
Blue	0.72	2.0	1.5
Red	0.72	1.5	2.0
Buff	0.42	1.5	1.5
Cyan	0.54	1.5	1.5
Magenta	0.54	2.0	2.0
Orange	0.54	1.0	2.0
Black	0.72	1.5	1.5
Dark Green	0.72	1.0	1.0
Dark Orange	0.72	1.0	2.0

Notes:

1) The colors shown are adjusted for maximum brightness and only approximate (different color spaces are used on TV and web pages).[8]

2) At least on the Color Computer 1 and 2, the alternate palette of text modes (actually the text portion of semigraphic modes) was dark pink (or dark red) on light pink, of shades not listed here (and no dark orange), whereas the Color Computer 3, with a different chip, made it dark orange on orange.

The first eight colors of this table were numbered 0 to 7 in the upper bits of the character set (when bit 7 was set, bits 4-6 represented the color number), but ColorBASIC's numbering was 1 higher than that in text mode, as it used 0 for black.

The built-in character generator ROM offers 64 ASCII characters with 5x7 pixels. Characters can be green or orange, on dark green or orange background, with a possible "invert" attribute (dark character on a bright background).[1]

• Motorola 6845, video address generator
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• Texas Instruments TMS9918
• MOS Technology VIC-II
• List of home computers by video hardware