Datasheet

Section 10 I/O Ports
R01UH0309EJ0500 Rev. 5.00 Page 647 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
10.13 Port E
Port E is an 8-bit I/O port that also has other functions. Port E has the following registers.
• Port E data direction register (PEDDR)
• Port E data register (PEDR)
• Port E register (PORTE)
• Port E pull-up MOS control register (PEPCR)
• Port E open drain control register (PEODR)
10.13.1 Port E Data Direction Register (PEDDR)
The individual bits of PEDDR specify input or output for the pins of port E. PEDDR cannot be
read; if it is, an undefined value will be read.
Bit Bit Name Initial Value R/W Description
7 PE7DDR 0 W
6 PE6DDR 0 W
5 PE5DDR 0 W
4 PE4DDR 0 W
3 PE3DDR 0 W
2 PE2DDR 0 W
1 PE1DDR 0 W
0 PE0DDR 0 W
• Modes 1, 2, and 4
When 8-bit bus mode is selected, port E is an I/O
port, and its pin functions can be switched with
PEDDR.
When 16-bit bus mode is selected, port E is
designated for data input/output.
For details on 8-bit and 16-bit bus modes, see
section 6, Bus Controller (BSC).
• Modes 3 and 7 (EXPE = 1)
When 8-bit bus mode is selected, port E is an I/O
port. Setting a PEDDR bit to 1 makes the
corresponding pin an output port, while clearing
a PEDDR bit to 0 makes the corresponding pin
an input port.
When 16-bit bus mode is selected, port E is
designated for data input/output.
• Modes 3 and 7 (EXPE = 0)
Port E is an I/O port, and its pin functions can be
switched with PEDDR.