R8C/13 Group
15. Programmable I/O Ports
15.3 Unassigned Pin Handling
Table 15.24 lists the handling of unassigned pins.
Table 15.24 Unassigned Pin Handling
Pin name
Connection
•After setting for input mode, connect every pin to VSS via a resistor(pull-down)
or connect every pin to VCC via a resistor(pull-up)
•Set to output mode and leave these pins open(1, 2)
Ports P0, P1, P3
P3 , P3 P4
0 to
3
7
5
Connect to VCC via resistor (pull-up)(2)
Connect to VCC
Ports P46, P47
AVCC, VREF
AVSS
Connect to VSS
Connect to VCC via a resistor (pull-up)(2)
RESET(3)
NOTES:
1. When these ports are set for output mode and left open, they remain input mode until they are set for
output mode by a program. The voltage level of these pins may be unstable and the power supply
current may increase for the time the ports remain input mode.
The content of the direction registers may change due to noise or runaway caused by noise. In order to
enhance program reliability, set the direction registers periodically by a program.
2. Connect these unassigned pins to the microcomputer using the shortest wire length (within 2 cm)
possible.
3. When power-on reset is used.
Microcomputer
Port P0, P1,
P3 to P3 , P37, P45
(Input mode)
0
3
:
:
:
:
(Input mode)
(Output mode)
Open
Port P46, P47
RESET(1)
AVCC/VREF
AVSS
NOTES:
1. When power-on reset function is used.
Figure 15.10 Unassigned Pin Handling
Rev.1.20 Jan 27, 2006 page 151 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
