UPD75112FGF datasheet(12/78 Pages) NEC

12 / 78 page

µPD75108F,75112F,75116F

3.5

PRECAUTIONS CONCERNING P00/INT4 PIN AND RESET PIN

In addition to the functions shown in 3.1 and 3.2, the P00/INT4 pin and RESET pin are also used to set the test

mode for testing internal

µPD75116F operation (for IC testing).

The test mode is set when a voltage greater than VDD is applied to either of these pins. Consequently, if noise

exceeding VDD is applied during normal operation, the test mode may be entered, making it impossible for normal

operation to continue.

If, for example, inter-wiring noise is applied to the P00/INT4 or RESET pin due to the length of the wiring from

these pins, and the pin voltage exceeds VDD, misoperation may result.

Wiring should therefore be carried out so that interwiring noise is suppressed as far as possible. If it is completely

impossible to suppress noise, noise prevention measures should be taken using an external component as shown

below.

Capacitor connected between

P00/INT4 or RESET and VDD

Diode with small VF (0.3 V or less) connected

between P00/INT4 or RESET and VDD

VDD

P00/INT4, RESET

Diode with

small VF

VDD

P00/INT4, RESET

UPD75112FGF Datasheet(PDF) 12 Page - NEC