Datasheet

Section 8 I/O Ports
Rev. 2.00 Sep. 28, 2009 Page 193 of 870
REJ09B0429-0200
8.3.4 Pin Functions
(1) Normal Extended Mode
Port 3 pins are automatically set to function as bidirectional data bus pins.
(2) Address-Data Multiplex Extended Mode
The operation is the same as that in single-chip mode.
(3) Single-Chip Mode
The pin function is switched as shown below according to the P3nDDR bit.
P3nDDR 0 1
Pin function P3n input pin P3n output pin
[Legend] n = 7 to 0
8.3.5 Port 3 Input Pull-Up MOS
Port 3 has built-in input pull-up MOSs that can be controlled by software. The input pull-up MOS
can be used in single-chip mode and address-data multiplex extended mode. Table 8.4 summarizes
the input pull-up MOS states.
Table 8.4 Port 3 Input Pull-Up MOS States
Mode Reset
Hardware
Standby Mode
Software Standby
Mode
In Other
Operations
Normal extended mode
(EXPE = 1, ADMXE = 0)
Off Off Off Off
Single-chip mode (EXPE = 0)
Address-data multiplex
extended mode (EXPE = 1,
ADMXE = 1)
Off Off On/Off On/Off
[Legend]
Off: Always off.
On/Off: On when input state and P3PCR = 1; otherwise off.