Datasheet

Section 8 I/O Ports
Rev. 4.00 Jun 06, 2006 page 212 of 1004
REJ09B0301-0400
8.4.4 MOS Input Pull-Up Function
Port 3 has an on-chip MOS input pull-up function that can be controlled by software. This MOS
input pull-up function can be used in modes 2 and 3 (when EXPE = 0), and can be specified as on
or off on a bit-by-bit basis.
When a P3DDR bit is cleared to 0 in mode 2 or 3 (when EXPE = 0), setting the corresponding
P3PCR bit to 1 turns on the MOS input pull-up for that pin.
The MOS input pull-up function is in the off state after a reset and in hardware standby mode. The
prior state is retained in software standby mode.
Table 8.8 summarizes the MOS input pull-up states.
Table 8.8 MOS Input Pull-Up States (Port 3)
Mode Reset
Hardware
Standby Mode
Software
Standby Mode
In Other
Operations
1, 2, 3 (EXPE = 1) Off Off Off Off
2, 3 (EXPE = 0) Off Off On/Off On/Off
Legend:
Off: MOS input pull-up is always off.
On/Off: On when P3DDR = 0 and P3PCR = 1; otherwise off.