UPD17P709 datasheet(21/38 Pages) NEC

21 / 38 page

µPD17P709

1.5 NOTES ON USE OF THE CE, INT0-INT4, AND RESET PINS (ONLY IN NORMAL OPERATION MODE)

The CE, INT0-INT4, and RESET pins can be used as the test mode selection pin for testing the internal operation

of the

µPD17P709 (IC test), besides the usage shown in Section 1.1.

Applying a voltage exceeding VDD to the CE, INT0-INT4, or RESET pin causes the

µPD17P709 to enter test mode.

When noise exceeding VDD comes in during normal operation, the device may not operate normally.

For example, if the wiring from the CE, INT0-INT4, or RESET pin is too long, noise may be induced on the wiring,

causing this mode switching.

When installing the wiring, lay the wiring in such a way that noise is suppressed as much as possible. If noise

yet arises, use an external part to suppress it as shown below.

• Connect a diode with low VF between the pin

• Connect a capacitor between the pin and VDD.

and VDD.

1.6 NOTES ON USE OF THE TEST PIN (ONLY IN NORMAL OPERATION MODE)

Applying VDD to the TEST pin causes the

µPD17P709 to enter test mode or program memory write/verify mode.

Keep the wiring as short as possible and connect the TEST pin directly to the GND pin.

When the wiring between the TEST pin and GND pin is too long or external noise enters the TEST pin, a voltage

difference may occur between the TEST pin and GND pin. When this happens, your program may malfunction.

VDD

CE, INT0-INT4, RESET

VDD

Diode with

low VF

CE, INT0-INT4, RESET

VDD

GND TEST

Keep the wiring as short as possible.

UPD17P709 Datasheet(PDF) 21 Page - NEC