157
Port Control Register E (PCRE)
Bit
7
6
5
4
3
2
1
0
—
—
—
—
PCRE
3
PCRE
2
—
—
Initial value
1
1
1
1
0
0
0
0
Read/Write
—
—
—
—
W
W
—
—
PCRE is a 2-bit register for controlling whether each of the port E pins PE
3
and PE
2
functions as
an input pin or output pin. Setting a PCRE bit to 1 makes the corresponding pin an output pin,
while clearing the bit to 0 makes the pin an input pin.
Upon reset, PCRE is initialized to H'F0.
PCRE is a write-only register. All bits are read as 1.
8.11.3
Pin Functions
Table 8.28 shows the port E pin functions.
Table 8.28
Port E Pin Functions
Pin
Pin Functions and Selection Method
PE
3
, PE
2
The pin function depends on bit PCRE
n
in PCRE.
(n = 3, 2)
PCRE
n
0
1
Pin function
PE
n
input pin
PE
n
output pin
8.11.4
Pin States
Table 8.29 shows the port E pin states in each operating mode.
Table 8.29
Port E Pin States
Pins
Reset
Sleep
Subsleep Standby
Watch
Subactive Active
PE
3
, PE
2
High-
impedance
Retains
previous
state
Retains
previous
state
High-
impedance
Retains
previous
state
Functional
Functional