M16C30P_07 Datasheet, PDF (209/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
18. Programmable I/O Ports
Table 18.2 Unassigned Pin Handling in Memory Expansion Mode and Microprocessor Mode
Pin Name
Connection
Ports P0 to P7,
After setting for input mode, connect every pin to VSS via a resistor (pull-
P8_0 to P8_4, P8_6 to P8_7, ^down);
P9 to P10
or after setting for output mode, leave these pins open. ^{(1, 2, 3, 4)}
P4_4/CS0 to P4_7/CS3
Connect to VCC via a resistor (pulled high) by setting the corresponding
direction bit in the PD4 register for CSi (i=0 to 3) to “0” (input mode) and
the CSi bit in the CSR register to “0” (chip select disabled).
BHE, ALE, HLDA, XOUT ⁽⁵⁾, Open
BCLK ⁽⁶⁾
HOLD, RDY
Connect via resistor to VCC (pull-up)
NMI (P8_5)
Connect via resistor to VCC (pull-up)
AVCC
Connect to VCC
AVSS, VREF
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. If the CNVSS pin has the VSS level applied to it, these pins are set for input ports until the processor
mode is switched over in a program after reset. For this reason, the voltage levels on these pins
become indeterminate, causing the power supply current to increase while they remain set for input
ports.
4. 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.
5. With external clock input to XIN pin.
6. If the PM07 bit in the PM0 register is set to “1” (BCLK not output), connect this pin to VCC via a
resistor (pulled high).
Rev.1.22 Mar 29, 2007 Page 193 of 291
REJ09B0179-0122