Memory Mapped I/0 ($Eooo-$E008) - Sharp MZ-700 Owner's Manual

4.3
Memory Mapped 1/0 ($EOOO-$E008)
Addresses
$EOOO
to
$E008
are assigned to the
8255
programmable peripheral interface,
8253
pro-
grammable interval timer and other 1/0 control ICs so that various 1/0 devices (including music functions
using counter
#0
of the
8253)
can be accessed in the same manner as memory. The memory mapped 1/0
chart is shown below.
CPU memory address
Controller Operation
$EOOO
PA: Output
$£001
,,
8255
Ps : Input
$E002
Pc : Input and output control by bit setting
$E003
Mode control
$E004
C
0 :
Mode
3
(square wave rate generator)
$E005
8253
C
1 :
Mode
2
(rate generator)
$E006
C
2 :
Mode
0
(terminal counter)
$E007
Mode control
$E008
LS367,
etc. Tempo, joystick and
HBLNK
input
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