R8C2K datasheet(85/471 Pages) RENESAS

85 / 471 page

R8C/2K Group, R8C/2L Group

7. Programmable I/O Ports

Rev.1.10

Dec 21, 2007

Page 68 of 450

REJ09B0406-0110

7.5

Unassigned Pin Handling

Table 7.37 lists the Unassigned Pin Handling.

NOTES:

1. If these ports are set to output mode and left open, they remain in input mode until they are switched

to output mode by a program. The voltage level of these pins may be undefined and the power

current may increase while the ports remain in input mode.

The content of the direction registers may change due to noise or program runaway caused by

noise. In order to enhance program reliability, the program should periodically repeat the setting of

the direction registers.

2. Connect these unassigned pins to the MCU using the shortest wire length (2 cm or less) possible.

3. When the power-on reset function is in use.

Figure 7.13

Unassigned Pin Handling

Table 7.37

Unassigned Pin Handling

Pin Name

Connection

Ports P0_0 to P0_3, P0_5, P1,

P2, P3_3 to P3_5, P4_5

• After setting to input mode, connect each pin to VSS via a resistor

(pull-down) or connect each pin to VCC via a resistor (pull-up).(2)

• After setting to output mode, leave these pins open.(1,2)

Ports P4_2, P4_6, P4_7

Connect to VCC via a pull-up resistor(2)

VREF

Connect to VCC

RESET (3)

Connect to VCC via a pull-up resistor(2)

NOTE:

1. When the power-on reset function is in use.

MCU

Ports P0_0 to P0_3,

P0_5, P1, P2,

P3_3 to P3_5,

P4_5

(Input mode )

(Input mode)

(Output mode)

Port P4_2, P4_6, P4_7

RESET(1)

VREF

Open

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