The MOS 6567/6569 video controller (VIC-II) and its application in the Commodore 64
Contents 3. Description of the VIC 3.7. Text/bitmap display 3.7.3. Graphics modes
3.7.3.2. Multicolor text mode (ECM/BMM/MCM=0/0/1) |
This mode allows for displaying four-colored characters at the cost of horizontal resolution. If bit 11 of the c-data is zero, the character is displayed as in standard text mode with only the colors 0-7 available for the foreground. If bit 11 is set, each two adjacent bits of the dot matrix form one pixel. By this means, the resolution of a character of reduced to 4×8 (the pixels are twice as wide, so the total width of the characters doesn't change). It is interesting that not only the bit combination "00" but also "01" is regarded as "background" for the sprite priority and collision detection. c-access
Adresses
13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
VM13 | VM12 | VM11 | VM10 | VC9 | VC8 | VC7 | VC6 | VC5 | VC4 | VC3 | VC2 | VC1 | VC0
Data
11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
MC flag | Color of "11" pixels | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0
g-access
Adresses
13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
CB13 | CB12 | CB11 | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | RC2 | RC1 | RC0
Data
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
MC flag=0
8 pixels (1 bit/pixel) "0": Background color 0 ($d021) "1": Color from bits 8-10 of c-data
MC flag=1
4 pixels (2 bits/pixel) "00": Background color 0 ($d021) "01": Background color 1 ($d022) "10": Background color 2 ($d023) "11": Color from bits 8-10 of c-data