HD6433937 Datasheet, PDF (181/521 Pages) Hitachi Semiconductor – Hardware Manual

2. Port control register 8 (PCR8)
Bit
Initial value
Read/Write
7
PCR8₇
0
W
6
PCR8₆
0
W
5
PCR8₅
0
W
4
PCR8₄
0
W
3
PCR8₃
0
W
2
PCR8₂
0
W
1
PCR8₁
0
W
0
PCR8₀
0
W
PCR8 is an 8-bit register for controlling whether each of the port 8 pins P8₇ to P8₀ 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
P8₇ to P8₀
Pin Functions and Selection Method
The pin function depends on bit PCR8_n in PCR8.
PCR8_n
Pin function
0
P8_n input pin
(n = 7 to 0)
1
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
P8₇ to P8₀
Reset
Sleep
High-
Retains
impedance previous
state
Subsleep
Retains
previous
state
Standby
High-
impedance
Watch
Retains
previous
state
Subactive Active
Functional Functional
169