UPD17P228 Просмотр технического описания (PDF) - NEC => Renesas Technology

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UPD17P228

4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROLLER

NEC => Renesas Technology 

µPD17P228

2.4 Processing of Unused Pins

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

IC1, IC2

Recommended Connection

Connect to VDD.

Connect to VDD.

Connect to GND.

Connect to GND.

Input : Individually connect to VDD or GND via resistor.

Output : Leave open.

Leave open.

Connect to GND.

Connect to VDD via resistor.

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

and RESET/INT pin

• Connect capacitor between VDD

and RESET/INT pin

VDD

VDD

Diode with

low VF

VDD

RESET, INT

VDD

RESET, INT

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

10

Data Sheet U14542EJ1V0DS00

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