Commodore PC 10 - Page 55

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Plantronics Graphics Mode
There are two submodes: 320 x 20016 colors and 640 x 200
4 colors. Each submode requires 32K bytes of memory at b8000 -
bfff. To
generate the extra colors, the video memory is split up into
two memory planes with 16K bytes each. (Refer to Section D.6.2
for detailed video
data format.) Plane 0 is located at b8000 - bbfff.
Plane 1 resides
at bcOOO - bffff or it can be mapped to reside at
b8000 - bbfff by setting bit 6 of register 3dd to 1.
Their memory organization is as follows:
b8000
b9f3f
baOOO
bbf3f
bbfff
Plane 0
Even scans lines
0,2,4,
... ,198
not used
Odd scans lines
1
,3 ,5 , ••. , 199
not used
ATI640 x 20016 Colors Mode
bcOOO
bdf3f
beOOO
bff3f
bffff
Plane 1
Even scans lines
o ,2 ,4 , ••• , 198
not used
Odd scans lines
1
,3 ,5 , •.• , 199
not used
In this mode, the video data format is the same as the 320 x 200
16 colors which requires 2 memory planes (refer to Section 6.6 for
detailed video data format). Each video plane requires 32K bytes of
memory with the following memory organization.
Plane 0
Plane 1
bOOOO
b8000
1 st scans lines
1st scans lines
o ,4 ,8, 12 , ••• , 196
0,4,8,12, ••• ,196
b1fff
b9fff
2nd scans lines
2nd scans lines
1,5,9,13, •••
,197
1,5,9,13, ••• ,197
b3fff
bbfff
3rd scans lines
3rd scans lines
2 ,6 , 1 0, 14, •• , 198
2,6,10,14, •. ,198
b5fff
bdfff
4th scans lines
4th scans lines
3,7,11,15, ••
,199
3,7,11,15, •• ,199
b7fff
bffff
Using ATI 3!