SM1126 View Datasheet(PDF) - Nippon Precision Circuits

Part Name

Description

Manufacturer

SM1126

Melody IC with Built-in SRAM

Nippon Precision Circuits  

SM1126 Series

FUNCTIONAL DESCRIPTION

Control Functions

External reference clock

SM1126 Series devices are available in external clock input versions and built-in RC oscillator versions, set

by master-slice option. In the case of the built-in RC oscillator option, an external resistor and capacitor is

required for the oscillator function.

SM1126 Series devices can operate at 6 selectable reference clock frequencies. All melodies playback at the

fixed speed set by the reference clock frequency. External clock input versions operate at one of 6 selectable

clock frequencies, as shown in table 1. Built-in RC oscillator versions operate at only one oscillator frequen-

cies—131.072 kHz.

Table 1. Reference clock frequencies (external clock)

Frequency

system

32.768 kHz

38.4 kHz

Selectable frequencies

32.768 kHz

38.4 kHz

65.536 kHz

76.8 kHz

131.072 kHz

153.6 kHz

Power-save function

In external clock input versions, the external reference clock input is used during playback mode only and is

otherwise ignored. If a clock signal is input when not in playback mode (when ST is LOW), the gate circuit

switches to cutoff the external reference clock signal from entering the device, preventing unwanted current

flow.

In built-in RC oscillator versions, the oscillator is stopped when not in playback mode (when ST is LOW),

preventing unwanted current flow.

ST

OSC

Figure 1. External clock input version: OSC input during playback mode only

ST

OSC

Figure 2. External clock input version: Continuous OSC input

ST

OSC

CR Oscillation

Figure 3. Built-in RC oscillator version

NIPPON PRECISION CIRCUITS—6

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