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2) Read/write from Z 80 to VRAM
(1) Timing period for display and
V-RAM Read/wrlte_
-
M 7
3~00
Dlplay period
H - S Y N C - - J I - - - - - - - - - - - -
BL~K-------~
(2) Timing that the
z-ao
can read/write V
RAM
The
z-ao
can read/write
VRAM
when GDC
FIFO
buffer is either empty or Full. and can be accessed by
3) Structure of character VRAM
(1) When read/write from GDC
#07FF
lA)
(8)
2KX8
2Kx4
ASC I I
Attribute
#0000
.
8bit
4 bit
DO
;0
D7
D8 -----I)] I
(2) During display
#07FF
lA)
(8)
2Kx8
2KX4
#0000
12b,
t
refreshing during the display period_
Number of
characters that can be read/write within one raster in
any mode_
lA)
(B)
,
,~
I
ASC I I ( 8b,
t )
I
I
- - - - - - - - -
- -
~
-
--
-
( 12blt )
DO
DJ
D2 D3 D4 D5
D6
I
I
I
m:DO Dl D2 D3
l
8lank
Reversp. (G)
Vertical line
(R)
HOrlzonwl line (B)
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