Datasheet
Section 10 I/O Ports 
R01UH0310EJ0500 Rev. 5.00    Page 521 of 1384 
Sep 25, 2012     
H8S/2426, H8S/2426R, H8S/2424 Group 
10.1  Port 1 
Port 1 is an 8-bit I/O port that also has other functions. Port 1 has the following registers. For the 
port function control registers, refer to section 10.18, Port Function Control Registers. 
•  Port 1 data direction register (P1DDR) 
•  Port 1 data register (P1DR) 
•  Port 1 register (PORT1) 
•  Port 1 open drain control register (P1ODR) 
•  Port function control register 5 (PFCR5) 
10.1.1  Port 1 Data Direction Register (P1DDR) 
The individual bits of P1DDR specify input or output for the pins of port 1. P1DDR cannot be 
read; if it is, an undefined value will be read. 
Bit  Bit Name  Initial Value  R/W  Description 
7 P17DDR 0  W 
6 P16DDR 0  W 
5 P15DDR 0  W 
4 P14DDR 0  W 
3 P13DDR 0  W 
2 P12DDR 0  W 
1 P11DDR 0  W 
0 P10DDR 0  W 
When a pin function is specified as a general 
purpose I/O, setting this bit to 1 makes the 
corresponding pin an output port, while clearing this
bit to 0 makes the corresponding pin an input port. 










