FUJITSU Semiconductor Controller MB89950/950A - Manual (Page 85)

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CHAPTER 4 I/O PORTS
Table 4.1-2 Port registers
Register Read/Write Address Initial value
Port 0 data register (PDR0)
R/W
0000
H
11111111
B
Port 1 data register (PDR1)
R/W
0002
H
11111111
B
Port 2 data register (PDR2)
R/W
0004
H
--111111
B
Port 3 data register (PDR3)
R/W
000C
H
----1111
B
Port 4 data register (PDR4)
R/W
000E
H
-XXXXXXX
B
Port 4 data direction register (DDR4)
W
000F
H
-0000000
B
R/W: Readable and writable
W: Write-only
X: Indeterminate
-: Unused