Sharp MZ-80B - Page 54

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Input and output of the V-RAM for graphic display can be controlled as follows by means of the
data delivered to
OUT port $F4.
Output data
V-RAM
GRPH I V-RAM GRPH IT
to port $F4
Input
Output Input
00
0
X
X
01 X
X
0
02 0
0
X
03 X
0
0
oc
0
X
X
OD
X
X
0
OE
0 0 X
OF X
0 0
Note Input 0: V-RAM transfer enabled
X : V-RAM transfer disabled
Output 0: shown on CRT display
X :
not shown on CRT display
Output
X
X
X
X
0
0
0
0
If 03H is delivered to port $F4 with OlH stored in $EOOO, then OlH is transferred to V-RAM G-ll
$EOOO but is not displayed on the CRT because the display indicator is set at V -RAM G-1.