Datasheet

Section 10 I/O Ports
Page 618 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
10.10 Port B
Port B is an 8-bit I/O port that also has other functions. Port B has the following registers.
• Port B data direction register (PBDDR)
• Port B data register (PBDR)
• Port B register (PORTB)
• Port B pull-up MOS control register (PBPCR)
• Port B open drain control register (PBODR)
10.10.1 Port B Data Direction Register (PBDDR)
The individual bits of PBDDR specify input or output for the pins of port B. PBDDR cannot be
read; if it is, an undefined value will be read.
Bit Bit Name Initial Value R/W Description
7 PB7DDR 0 W
6 PB6DDR 0 W
5 PB5DDR 0 W
4 PB4DDR 0 W
3 PB3DDR 0 W
2 PB2DDR 0 W
1 PB1DDR 0 W
0 PB0DDR 0 W
• Modes 1 and 2
Port B pins are address outputs regardless of the
PBDDR settings.
• Mode 4 Modes 3 and 7 (EXPE = 1)
Setting a PBDDR bit to 1 makes the
corresponding pin an address output, while
clearing a PBDDR bit to 0 makes the
corresponding pin an input port.
• Modes 3 and 7 (EXPE = 0)
Port B is an I/O port, and its pin functions can be
switched with PBDDR.