M16C6S_09 Datasheet, PDF (147/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Programmable I/O Ports
Table 1.18.1. Unassigned Pin Handling in Single-chip Mode (Excluding Analog Pins)
Pin name
Connection
Ports P1, P6 to P9
(excluding P85)
After setting for input mode, connect every pin to V SS via a resistor(pull-down);
or after setting for output mode, leave these pins open. (2, 3, 4)
XOUT (Note 1)
Open
P85
Connect via resistor to VCC (pull-up)
VCCA
Connect to VCC
VSSA
Connect to VSS
NOTES:
1. With external clock input to XIN pin.
2. 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.
3. Make sure the unused pins are processed with the shortest possible wiring from the microcomputer pins
(within 2 cm).
4. When the port P7_0 is set for output mode, make sure a low-level signal is output from the pin.
The port P7_0 is N-channel open-drain output.
Rev.5.01 Dec 10, 2009 page 147 of 201
REJ03B0014-0501