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5.9.2
Register Configuration
Table 5.15 shows the port 8 register configuration.
Table 5.15 Port 8 Registers
Name
Port 8 data direction register
Port 8 data register
Port 8 register
Notes: 1. Lower 16 bits of the address.
2. Value of bits 5 to 0.
Port 8 Data Direction Register (P8DDR)
Bit
7
—
Initial value
0
Read/Write
—
P8DDR is a 6-bit write-only register, the individual bits of which specify input or output for the
pins of port 8. P8DDR cannot be read; if it is, an undefined value will be read. Bits 7 and 6 are
reserved.
Setting a P8DDR bit to 1 makes the corresponding port 8 pin an output pin, while clearing the bit
to 0 makes the pin an input pin.
P8DDR is initialized to H'00 by a reset and in hardware standby mode. It retains its prior state in
software standby mode.
Port 8 Data Register (P8DR)
Bit
7
—
Initial value
0
Read/Write
—
P8DR is a 6-bit readable/writable register that stores output data for the port 8 pins (P85 to P80).
Bits 7 and 6 are reserved; they are always read as 0 and cannot be modified.
Abbreviation
P8DDR
P8DR
PORT8
6
5
—
P85DDR P84DDR P83DDR P82DDR P81DDR P80DDR
0
0
—
W
6
5
—
P85DR
P84DR
0
0
—
R/W
R/W
Initial Value
W
H'00*
R/W
H'00*
R
Undefined
4
3
0
0
W
W
4
3
P83DR
P82DR
0
0
R/W
R/W
Address*
2
H'FE27
2
H'FF67
H'FF57
2
1
0
0
W
W
2
1
P81DR
P80DR
0
0
R/W
R/W
1
0
0
W
0
0
R/W
241
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