Caution; Handling Of Unused Pins - Renesas R-IN32M4-CL3 User Manual

R-IN32M4-CL3 User's Manual: Board design edition
8.3

Caution

8.3.1

Handling of Unused Pins

If an unused pin is clamped to the GND or a power supply on the board, the corresponding pin must have the input
attribute as a fixed setting. If it is set as an output, and the level at the point to which it is clamped is opposite that of the
pin, a large steady-state current will continuously flow through the output buffer.
On the other hand, if an unused pin is open-circuit on the board, the corresponding pin can have either the output attribute
or the input attribute as a fixed setting, accompanied by enabling of the pull-up or pull-down resistor. Setting a pin as an
input without enabling a pull-up or pull-down resistor may lead to the pin being in a floating state and the flow of a
through-type current.
Since the above factors lead to unnecessary heating, be sure to check the settings made by the software in these cases.
R-IN32M4-CL3
Output mode enabled
R18UZ0074EJ0100
Dec 24, 2019
VDD33 (3.3 V)
VDD33 (3.3 V)
Steady-state
current
R-IN32M4-CL3
VDD33 (3.3 V)
Through-type
current
VDD33 (3.3 V)
Output mode disabled
8. Thermal Design
Open-circuit
(floating)
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