Sharp MZ-80B - Page 52

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On the other hand, when the V-RAM is accessed with the program in main memory following
$DOOO, the V-RAM addresses may be changed to $5000 to $7FFF by setting the A
6
terminal of PIO
to high state.
That is, the following instructions are executed.
IN A, (E8H)
SET 6, A
SET 7, A
OUT (E8H), A
This address switching
is shown in FIGURE 4.5.
Address
$0000 .--------,--::o
RAMI
Switching by PIO A
6
$5000
$5FFF
$6000
$7FFF
$8000
RAM I
RAM I
RAM II
(Option)
$FFFF~----~-~
V-RAM
Character
r
V-RAM
Graphic I
Addr .
(Option)
~
Page 1
Switching
by OUT port $F4
V-RAM
Graphic
II
(Option)
Page 2
FIGURE 4.5 Switching
of main memory and V- RAM (2)