M306H7MG-XXXFP Datasheet, PDF (262/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
15. PROGRAMMABLE I/O PORTS
Table 15.1 Unassigned Pin Handling in Single-chip Mode
Pin name
Connection
Ports P0 to P7, P80 to P84, ^{After setting for input mode, connect every pin to VSS via a resistor(pull-down);}
P86 to P87, P9
or after setting for output mode, leave these pins open. (Note 1, 2 ,3)
XOUT (Note 4)
Open
NMI (P85)
Connect via resistor to VCC (pull-up)
AVCC
Connect to VCC
AVSS
Connect to VSS
Note 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.
Note 2: Make sure the unused pins are processed with the shortest possible wiring from the microcomputer pins
(within 2 cm).
Note 3: When the ports P70 and P71 are set for output mode, make sure a low-level signal is output from the pins.
The ports P70 and P71 are N-channel open-drain outputs.
Note 4: With external clock input to XIN pin.
Microcomputer
Port P0 to P9 (except for P85)
(Input mode)
••
(Input mode)
(Output mode)
NMI
XOUT
AVCC
••
Open
Open
VCC
AVSS
VSS
In single-chip mode
Figure 15.11 Unassigned Pins Handling
Rev.2.10 Oct 25, 2006 Page 262 of 326
REJ03B0152-0210