M16C30P_07 Datasheet, PDF (208/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
18. Programmable I/O Ports
Table 18.1 Unassigned Pin Handling in Single-chip Mode
Pin Name
Ports P0 to P7,
P8_0 to P8_4, P8_6 to P8_7,
P9 to P10
XOUT ⁽⁴⁾
NMI (P8_5)
AVCC
AVSS, VREF, BYTE
Connection
After setting for input mode, connect every pin to VSS via a resistor (pull-
down);
or after setting for output mode, leave these pins open. ^{(1, 2, 3)}
Open
Connect via resistor to VCC (pull-up)
Connect to VCC
Connect to VSS
NOTES:
1. When setting the port for output mode and leave it open, be aware that the port remains in input
mode until it is switched to output mode in a program after reset. For this reason, the voltage level
on the pin becomes indeterminate, causing the power supply current to increase while the port
remains in input mode.
Furthermore, by considering a possibility that the contents of the direction registers could be
changed by noise or noise-induced runaway, it is recommended that the contents of the direction
registers be periodically reset in software, for the increased reliability of the program.
2. Make sure the unused pins are processed with the shortest possible wiring from the microcomputer
pins (within 2 cm).
3. When the ports P7_0 and P7_1 are set for output mode, make sure a low-level signal is output from
the pins.
The ports P7_0 and P7_1 are N-channel open-drain outputs.
4. With external clock input to XIN pin.
Rev.1.22 Mar 29, 2007 Page 192 of 291
REJ09B0179-0122