Datasheet

Section 8 I/O Ports
Rev. 2.00 Sep. 28, 2009 Page 194 of 870
REJ09B0429-0200
8.4 Port 4
Port 4 is an 8-bit I/O port. Port 4 pins can also function as the external interrupt input pins. Port 4
has the following registers.
• Port 4 data direction register (P4DDR)
• Port 4 data register (P4DR)
• Port 4 pull-up MOS control register (P4PCR)
8.4.1 Port 4 Data Direction Register (P4DDR)
The individual bits of P4DDR specify input or output for the port 4 pins. P4DDR is initialized
only by a system reset, and retains the value even if an internal reset signal of the WDT is
generated.
Bit Bit Name Initial Value R/W Description
7 P47DDR 0 W
6 P46DDR 0 W
5 P45DDR 0 W
4 P44DDR 0 W
3 P43DDR 0 W
2 P42DDR 0 W
1 P41DDR 0 W
The corresponding pins function as output port when
the P4DDR bits are set to 1, and as input port when
cleared to 0.
0 P40DDR 0 W