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2. Port control register 8 (PCR8)
Bit
Initial value
Read/Write
7
PCR8
0
W
6
PCR8
0
W
5
PCR8
0
W
4
PCR8
0
W
3
PCR8
0
W
0
PCR8
0
W
2
PCR8
0
W
1
PCR8
0
W
7
6
5
4
3
2
1
0
PCR8 is an 8-bit register for controlling whether each of the port 8 pins P8
7
to P8
0
functions as an
input or output pin. Setting a PCR8 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin.
Upon reset, PCR8 is initialized to H'00.
PCR8 is a write-only register, which is always read as all 1s.
8.9.3
Pin Functions
Table 8-24 shows the port 8 pin functions.
Table 8-24 Port 8 Pin Functions
Pin
Pin Functions and Selection Method
P8
7
to P8
0
The pin function depends on bit PCR8
n
in PCR8.
(n = 7 to 0)
PCR8
n
0
1
Pin function
P8
n
input pin
P8
n
output pin
8.9.4
Pin States
Table 8-25 shows the port 8 pin states in each operating mode.
Table 8-25 Port 8 Pin States
Pins
Reset
Sleep
Subsleep
Standby
Watch
Subactive
Active
P8
7
to P8
0
High-
impedance
Retains
previous
state
Retains
previous
state
High-
impedance
Retains
previous
state
Functional
Functional
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