CF1156 series

SEIKO NPC CORPORATION —4

FUNCTIONAL DESCRIPTION

LED Indicator

The LED flashes during melody play mode only, at intervals representing a 1/8 musical note length.

Melody Modes

The CF1156 series melody mode is determined by the bonding options and levels on the mode control inputs

shown in the following table.

Level hold 1

When both OSH and LH go HIGH, melody play starts and continues while both are held HIGH. When both

inputs go open circuit or LOW, melody play stops, even if during mid melody.

Note that both OSH and LH inputs should be switched simultaneously using a single switch. If there is timing

difference between the two inputs, then LH has priority.

OSH

LH

Melody mode

HIGH

HIGH

Level hold 1

LOW

HIGH

Level hold 2

HIGH

LOW

One-shot

LOW

LOW

Non-play

= 1 cycle

BO

LED flash

LED flash interval

LO

Play

Non-play

Active:LOW

The LED flashes at intervals equal to a 1/8 musical note,

regardless of the melody note length being output.

Note:

1 TUNE

Oscillator

REPEAT

REPEAT

BO

LH

OSH

150k

Ω

45k

Ω

45k

Ω

Pull-down resistance

(2-pin parallel resistance)