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
3.7.3.9. Idle state |
In idle state, the VIC reads the graphics data from address $3fff (resp. $39ff if the ECM bit is set) and displays it in the selected graphics mode, but with the video matrix data (normally read in the c-accesses) being all "0" bits. So the byte at address $3fff/$39ff is output repeatedly. c-access No c-accesses occur.
Data
11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
g-access
Adresses (ECM=0)
13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1
Adresses (ECM=1)
13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1
Data
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
Standard text mode Multicolor text mode ECM text mode
8 pixels (1 bit/pixel) "0": Background color 0 ($d021) "1": Black
Standard bitmap mode Invalid text mode Invalid bitmap mode 1
8 pixels (1 bit/pixel) "0": Black (background) "1": Black (foreground)
Multicolor bitmap mode
4 pixels (2 bits/pixel) "00": Background color 0 ($d021) "01": Black (background) "10": Black (foreground) "11": Black (foreground)
Invalid bitmap mode 2
4 pixels (2 bits/pixel) "00": Black (background) "01": Black (background) "10": Black (foreground) "11": Black (foreground)