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9.8.2
Register Configuration
Table 9-13 shows the port B register configuration.
Table 9-13 Port B Registers
Name
Abbreviation
R/W
Initial Value
Address*
Port B data direction register
PBDDR
W
H'00
H'FE3A
Port B data register
PBDR
R/W
H'00
H'FF0A
Port B register
PORTB
R
Undefined
H'FFBA
Port B MOS pull-up control register
PBPCR
R/W
H'00
H'FE41
Note: * Lower 16 bits of the address.
(1) Port B Data Direction Register (PBDDR)
7
PB7DDR
0
W
6
PB6DDR
0
W
5
PB5DDR
0
W
4
PB4DDR
0
W
3
PB3DDR
0
W
0
PB0DDR
0
W
2
PB2DDR
0
W
1
PB1DDR
0
W
Bit
:
Initial value :
R/W
:
PBDDR is an 8-bit write-only register, the individual bits of which specify input or output for the
pins of port B. PBDDR cannot be read; if it is, an undefined value will be read.
PBDDR is initialized to H'00 by a power-on reset and in hardware standby mode. It retains its
previous state after a manual reset and in software standby mode. The OPE bit in SBYCR is used
to select whether the address output pins retain their output state or become high-impedance when
a transition is made to software standby mode.
(a)Modes 4, 5, and 6
If address output is enabled by the setting of bits AE3 to AE0 in PFCR, the corresponding port
B pins are address outputs.
When address output is disabled, setting a PBDDR bit to 1 makes the corresponding port B pin
an output port, while clearing the bit to 0 makes the pin an input port.
(b)Mode 7
Setting a PBDDR bit to 1 makes the corresponding port B pin an output port, while clearing
the bit to 0 makes the pin an input port.