Port B; Port B Data Direction Register (Pbddr) - Hitachi H8S/2378, H8S/2378R Series Hardware Manual

10.10

Port B

Port B is an 8-bit I/O port that also has other functions. The port B has the following registers.

• Port B data direction register (PBDDR)

• Port B data register (PBDR)
• Port B register (PORTB)
• Port B MOS pull-up control register (PBPCR)
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
7 PB7DDR
6 PB6DDR
5 PB5DDR
4 PB4DDR
3 PB3DDR
2 PB2DDR
1 PB1DDR
0 PB0DDR
Rev. 1.0, 09/01, page 460 of 904
Initial Value R/W
0 W
0 W
0 W
0 W
0 W
0 W
0 W
0 W
Description
•
Modes 1, 2, 5, and 6
Port B pins are address outputs regardless of the
PBDDR settings.
•
Modes 4 and 7 (when EXPE = 1)
Setting a PBDDR bit to 1 makes the corresponding
port B pin an address output, while clearing the bit to
0 makes the pin an input port.
•
Modes 7 (when EXPE = 0)
Port B is an I/O port, and its pin functions can be
switched with PBDDR.