msm9810 Oki Semiconductor, msm9810 Datasheet - Page 24

• Manufacturer Part Number: msm9810
• Description: 8-channel Mixing Oki Adpcm Type Voice Synthesis Lsi
• Manufacturer: Oki Semiconductor

¡ Semiconductor
register. Table 9-7 shows the correspondence between data input (D7 to D0) and options.
(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.
9-4 OPT Command
The OPT command changes the setting inside the LSI according to data stored in the TMP
Table 9-7 Correspondence between D7-D0 and options
D4
0
0
1
1
D3
D2
D1
D0
0
1
0
1
0
1
0
1
0
1
Sets volume of all channels to V
Sets volume of all channels to 1/2V
Sets volume of all channels to 1/4V
Sets volume of all channels to 1/8V
Uses internal LPF.
Does not use internal LPF.
Executes 2nd digital filter processing.
Executes 1st digital filter processing.
Outputs directly from the D/A converter.
Outputs via a voltage follower.
Option
Option
Option
Option
DD(P-P).
DD(P-P).
DD(P-P).
DD(P-P).
MSM9810
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