MSM9810 View Datasheet(PDF) - Oki Electric Industry

Part Name

Description

Manufacturer

MSM9810

8-channel Mixing OKI ADPCM Type Voice Synthesis LSI

Oki Electric Industry 

¡ Semiconductor

MSM9810

9-4 OPT Command

The OPT command changes the setting inside the LSI according to data stored in the TMP

register. Table 9-7 shows the correspondence between data input (D7 to D0) and options.

Table 9-7 Correspondence between D7-D0 and options

D4 D3

Option

0 0 Sets volume of all channels to VDD(P-P).

0 1 Sets volume of all channels to 1/2VDD(P-P).

1 0 Sets volume of all channels to 1/4VDD(P-P).

1 1 Sets volume of all channels to 1/8VDD(P-P).

D2

Option

0 Uses internal LPF.

1 Does not use internal LPF.

D1

Option

0 Executes 2nd digital filter processing.

1 Executes 1st digital filter processing.

D0

Option

0 Outputs directly from the D/A converter.

1 Outputs via a voltage follower.

(Input “L” to D7-D5.)

When the OPT command is input, the LSI changes the option at the rising edge of the WR pulse.

When power is turned on, or when the RESET pulse is input, the registers corresponding to D3-

D0 have been set to “L”.

If the option is changed when voice synthesis is in execution, voice quality may change. Oki

recommends to set the option after power is turned on or after RESET is input.

1) Volume Option

Volume can be set by the CVOL command and PAN command, but a waveform may be clamped

when channel synthesis is executed.

If the CVOL command and PAN command are used to prevent a waveform from being clamped,

the number of steps used for actual volume decreases, and effective voice synthesis may not be

performed.

If it is known that a waveform will be clamped, this option can set the volume of all channels to

low, so that the number of steps of the volume can be utilized to the maximum level.

2) Digital Filter Processing

This LSI has a built-in oversampling circuit for digital filter processing. This oversampling

system evenly generates four times more points of sampling frequencies.

When power is turned on or if the RESET pulse is input, those pulses have been set to pass

through the oversampling circuit. If digital filter processing is unnecessary, change this setting

by the OPT command.

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