Datasheet

Section 9 I/O Ports
Rev. 2.00 Sep. 23, 2005 Page 126 of 444
REJ09B0068-0200
9.7.1 Port Control Register 8 (PCR8)
PCR8 selects inputs/outputs in bit units for pins to be used as general I/O ports of port 8.
Bit Bit Name
Initial
Value R/W Description
7
6
5
PCR87
PCR86
PCR85
0
0
0
W
W
W
When each of the port 8 pins P87 to P85 functions as a
general I/O port, setting a PCR8 bit to 1 makes the
corresponding pin an output port, while clearing the bit
to 0 makes the pin an input port.
4 to 0    Reserved
9.7.2 Port Data Register 8 (PDR8)
PDR8 is a general I/O port data register of port 8.
Bit Bit Name
Initial
Value R/W Description
7
6
5
P87
P86
P85
0
0
0
R/W
R/W
R/W
PDR8 stores output data for port 8 pins.
If PDR8 is read while PCR8 bits are set to 1, the value
stored in PDR8 is read. If PDR8 is read while PCR8 bits
are cleared to 0, the pin states are read regardless of
the value stored in PDR8.
4 to 0  All 1  Reserved
These bits are always read as 1.
9.7.3 Pin Functions
The correspondence between the register specification and the port functions is shown below.
• P87 pin
Register PCR8
Bit Name PCR87 Pin Function
Setting Value 0 P87 input pin
1 P87 output pin