Pin States - Hitachi H8/3937 Series Hardware Manual

2. Port control register A (PCRA)
Bit 7
—
Initial value 1
Read/Write —
PCRA controls whether each of port A pins PA
Setting a PCRA bit to 1 makes the corresponding pin an output pin, while clearing the bit to 0
makes the pin an input pin.
Upon reset, PCRA is initialized to H'F0.
PCRA is a write-only register, which always reads all 1s.
8.11.3 Pin Functions
Table 8-30 shows the port A pin functions.
Table 8-30 Port A Pin Functions
Pin Pin Functions and Selection Method
PA to PA The pin function depends on bit PCRA
3 0
8.11.4

Pin States

Table 8-31 shows the port A pin states in each operating mode.
Table 8-31 Port A Pin States
Pins Reset
PA to PA High-
3 0
impedance
174
6 5
— —
1 1
— —
PCRA
n
Pin function
Sleep Subsleep
Retains Retains
previous previous
state state
4 3
— PCRA PCRA
3
1 0
— R/W
to PA functions as an input pin or output pin.
3 0
in PCRA.
n
0
PA input pin
n
Standby Watch
High- Retains
impedance previous
state
2 1
PCRA PCRA
2 1
0 0
R/W R/W R/W
(n = 3 to 0)
1
PA output pin
n
Subactive Active
Functional Functional
0
0
0