UPD17P228 datasheet(10/28 Pages) NEC

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µPD17P228

Data Sheet U14542EJ1V0DS00

2.4 Processing of Unused Pins

Process the unused pins as follows:

Table 2-1. Processing of Unused Pins

Recommended Connection

P0A0-P0A3

Connect to VDD.

P0B0-P0B3

Connect to VDD.

P0C0-P0C3

Connect to GND.

P0D0-P0D3

Connect to GND.

P0E0-P0E3

Input

: Individually connect to VDD or GND via resistor.

Output : Leave open.

REM

Leave open.

INT

Connect to GND.

WDOUT

Connect to VDD via resistor.

IC1, IC2

These pins cannot be used.

Leave open.

2.5 Notes on Using the RESET and INT Pins

In addition to the functions shown in 2. PIN FUNCTION, the RESET pin also has the function of setting a test mode

(for IC testing) in which the internal operations of the

µPD17P228 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

µPD17P228 may be set in the test mode if noise exceeding VDD is applied.

For example, if the wiring length of the RESET or INT 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

• Connect capacitor between VDD

and RESET/INT pin

Connect the WDOUT and RESET pins since a low level is output after the test mode is set using the INT pin.

VDD

RESET, INT

VDD

RESET, INT

Diode with

low VF

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