Datasheet

Section 10 I/O Ports
Rev. 6.00 Mar. 18, 2010 Page 309 of 982
REJ09B0054-0600
10.1 Port 1
Port 1 is an 8-bit I/O port and has the following registers.
• Port 1 data direction register (P1DDR)
• Port 1 data register (P1DR)
• Port 1 register (PORT1)
10.1.1 Port 1 Data Direction Register (P1DDR)
P1DDR specifies input or output of the port 1 pins using the individual bits. P1DDR 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 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
When a pin is specified as a general purpose I/O
port, setting this bit to 1 makes the corresponding
port 1 pin an output pin. Clearing this bit to 0
makes the pin an input pin.
0 P10DDR 0 W