UPD17P218CT Ver la hoja de datos (PDF) - NEC => Renesas Technology

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Fabricante

UPD17P218CT

4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROLLER

NEC => Renesas Technology 

µPD17P218

2.4 PROCESSING OF UNUSED PINS

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Process the unused pins as follows:

Table 2-1 Processing of Unused Pins

Pin

P0A0-P0A3

P0B0-P0B3

P0C0-P0C3

P0D0-P0D3

P0E0-P0E3

REM

INT

WDOUT

Recommended Connection

Connect to VDD

Connect to VDD

Connect to GND

Connect to GND

Input : Connect to VDD or GND

Output : Open

Open

Connect to GND

Connect to GND

2.5 NOTES ON USING INT AND RESET PINS

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In addition to the functions shown in 2 PIN FUNCTIONS, the INT and RESET pins also have a function to set a

test mode (for IC testing) in which the internal operations of the µPD17P218 are tested.

When a voltage higher than VDD is applied to either of these pins, the test mode is set. This means that, even

during normal operation, the µPD17P218 may be set in the test mode and malfunction if a noise exceeding VDD is

applied.

For example, if the wiring length of the INT or RESET pin is too long, noise superimposed on the wiring line of

the pin may cause the above problem.

Therefore, keep the wiring length of these pins as short as possible to suppress the noise; otherwise, take noise

preventive measures as shown below by using external components.

• Connect diode with low VF between VDD

and INT/RESET pin

• Connect capacitor between VDD

and INT/RESET pin

V DD

V DD

Diode with

low V F

V DD

INT, RESET

V DD

INT, RESET

Moreover, if the test mode is set by the INT pin, low level is output from the WDOUT pin. In this case, connect

the WDOUT pin to the RESET pin.

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