SM1350 series

NIPPON PRECISION CIRCUITS—7

FUNCTIONAL DESCRIPTION

Chattering Prevention

STN, STOP chattering prevention function

Standby Mode

The oscillator starts when STN goes from HIGH to

LOW in standby mode. Input data is received and

melody data output starts 81.9 ms after the oscillator

starts if STN is LOW.

Oscillator starts running

After the oscillator starts running, input data is

considered valid 81.9 ms after STN and STOP have

last changed state. Input data is considered invalid

for intervals less than 65.5 ms.

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 1. STN, STOP chattering prevention timing (standby mode)

STN

OSC

Input

Reception

81.9ms

81.9ms

Melody

Output

Internal

Clock

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 2. STN, STOP chattering prevention timing ( oscillator running)

81.9ms

65.5ms

STN or

STOP

Input

Reception

Internal

Clock