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9.7.2
Register Configuration
Table 9-10 shows the port A register configuration.
Table 9-10 Port A Registers
Name
Abbreviation
R/W
Initial Value*
2
Address*
1
Port A data direction register
PADDR
W
H'0
H'FE39
Port A data register
PADR
R/W
H'0
H'FF09
Port A register
PORTA
R
Undefined
H'FFB9
Port A MOS pull-up control register
PAPCR
R/W
H'0
H'FE40
Port A open-drain control register
PAODR
R/W
H'0
H'FE47
Notes: *1 Lower 16 bits of the address.
*2 Value of bits 3 to 0.
(1) Port A Data Direction Register (PADDR)
7
—
Undefined
—
6
—
Undefined
—
5
—
Undefined
—
4
—
Undefined
—
3
PA3DDR
0
W
0
PA0DDR
0
W
2
PA2DDR
0
W
1
PA1DDR
0
W
Bit
:
Initial value :
R/W
:
PADDR is an 8-bit write-only register, the individual bits of which specify input or output for the
pins of port A. PADDR cannot be read; if it is, an undefined value will be read.
Bits 7 to 4 are reserved; these bits cannot be modified and will return an undefined value if read.
PADDR is initialized to H'0 (bits 3 to 0) 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
A pins are address outputs.
When address output is disabled, setting a PADDR bit to 1 makes the corresponding port A pin
an output port, while clearing the bit to 0 makes the pin an input port.
(b)Mode 7
Setting a PADDR bit to 1 makes the corresponding port A pin an output port, while clearing
the bit to 0 makes the pin an input port.