Canon AS-100M Field Service Manual page 16

1.2.3 DISPLAY CONT
When video memory data (VRAM) [black/white display: 32KB x 1
(VRAM-B) and color display: 32KB x 3 (VRAM-B.G.R)]
Black/white or color display gives a full graphic presentation
of characters or figures.
controller (GDC) is yPD 7220D.
accessable on a time sharing basis either the GDC or the CPU
via the I/O bus.
Picture structure of both black/white and color display is as
shown in Fig. ].2.4.
640 dots
For black/white and color displays, a pallet display
system is employed and eight different patterns made from
3 VRAMs enhances display performance.
display system concept.
Display control too graphic display
32KB x 1 or 32KB x 3 VRAM is
0 1 2 * 7 9
...
31920
Fig. 1.2.4
1-10
(color display only)
i --------------
(bytl
)=80x8=&40 bit
t - -
AN: 80 characters x 25 lines
Fig. 1.2.5 shows pallet
1
'
I
R I
1
or