Datasheet

Section 10 I/O Ports
Rev. 6.00 Mar. 18, 2010 Page 315 of 982
REJ09B0054-0600
10.2 Port 3
Port 3 is a general 7-bit I/O port and has the following registers.
The P34, P35, and SCK1 function as NMOS push/pull outputs.*
• Port 3 data direction register (P3DDR)
• Port 3 data register (P3DR)
• Port 3 register (PORT3)
• Port 3 open drain control register (P3ODR)
Note: * Function as CMOS outputs in the H8S/2237 Group and H8S/2227 Group.
10.2.1 Port 3 Data Direction Register (P3DDR)
P3DDR specifies input or output of the port 3 pins using the individual bits.
P3DDR cannot be read; if it is, an undefined value will be read.
This register is a write-only register, and cannot be written by bit manipulation instruction. For
details, see section 2.9.4, Access Methods for Registers with Write-Only Bits.
Bit Bit Name Initial Value R/W Description
7 — Undefined — Reserved
These bits are always read as undefined value.
6 P36DDR 0 W
5 P35DDR 0 W
4 P34DDR 0 W
3 P33DDR 0 W
2 P32DDR 0 W
1 P31DDR 0 W
When a pin is specified as a general purpose I/O
port, setting this bit to 1 makes the corresponding
port 3 pin an output port. Clearing this bit to 0
makes the pin an input port.
0 P30DDR 0 W