Commodore Plus 4 - Page 220

208 Programming Graphics
The background color registers are all global color sources. This means you have
four global (whole screen) colors. The foreground bits use the normal color
memory to get their color (and luminance), so each character can have an
independent foreground color.
To enter extended color mode, use
POKE 65286,PEEK(65286)0R64
To put the chip back in high-resolution mode, use
POKE 65286,PEEK(65S86)AUD191
The background registers 65301-65304, which are used for coloring the back
ground pixels, can be assigned any of the 16 colors and 8 luminances. To calculate
the value needed, use
luminance * 16+color-1
where the luminance is 0 through 7, and the color is chosen from the available
colors (1-16). The color assigned to background registers 63501 and 63502 can
also be controlled by the COLOR command for sources 0 and 3, respectively. The
remaining two color registers cannot be changed with the COLOR command.
Note: In extended background color mode, the cursor is invisible. It is a good
idea to return to high-resolution character mode when exiting a program.
Example: 10 SCNCLR
20 POKE65286, PEEK (65286 )OR64
30 FORI=1TO4
40 PRINT"COLOR, LUMINANCE FOR";I;:INPUTC,L
50 POKE65300+I,L*16+C-1:NEXT
60 FORI=0TO63
70 POKE3072+I,I
80 POKE3136+I,I+64
90 POKE3200+I,1+128
100 POKE3264+I,1+192
110 NEXT
120 1=0
130 PORC=0TO15:FORL=0TO7
140 POKE2048+IrL*16+C
150 POKE2176+I,L*16+C
160 1=1+1
170 NEXTL,C
180 PRINT"HIT KEY":GETKEYK$:POKE65286rPEEK(65286)ANDl91
190 COLOR0,2,7