1. Port data register 3 (PDR3)
Bit
7
P37
0
6
P36
0
5
P35
0
4
P34
0
3
P33
0
2
P32
0
1
P31
0
0
P30
0
Initial value
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
PDR3 is an 8-bit register that stores data for port 3 pins P37 to P30. If port 3 is read while PCR3
bits are set to 1, the values stored in PDR3 are read, regardless of the actual pin states. If port 3 is
read while PCR3 bits are cleared to 0, the pin states are read.
Upon reset, PDR3 is initialized to H'00.
2. Port control register 3 (PCR3)
Bit
7
6
5
4
3
2
1
0
PCR37 PCR36 PCR35 PCR34 PCR33 PCR32 PCR31 PCR30
Initial value
Read/Write
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
PCR3 is an 8-bit register for controlling whether each of the port 3 pins P37 to P30 functions as an
input pin or output pin. Setting a PCR3 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin. The settings in PCR3 and in PDR3 are valid only
when the corresponding pin is designated in PMR3 as a general I/O pin.
Upon reset, PCR3 is initialized to H'00.
PCR3 is a write-only register, which is always read as all 1s.
3. Port pull-up control register 3 (PUCR3)
Bit
7
6
5
4
3
2
1
0
PUCR37 PUCR36 PUCR35 PUCR34 PUCR33 PUCR32 PUCR31 PUCR30
Initial value
Read/Write
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
PUCR3 controls whether the MOS pull-up of each of the port 3 pins P37 to P30 is on or off. When
a PCR3 bit is cleared to 0, setting the corresponding PUCR3 bit to 1 turns on the MOS pull-up for
the corresponding pin, while clearing the bit to 0 turns off the MOS pull-up.
Upon reset, PUCR3 is initialized to H'00.
146
ETC [ ETC ]
