MS87V1021 datasheet(53/63 Pages) OKI

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PEDS87V1021-01

1Semiconductor

MS87V1021

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Controlling Addresses in Retroactive Play Mode

In Retroactive Play Mode, four registers are defined within the internal Record/Play register. Those are the

record/play_start address (Stadr), the record/play_end address (Enadr), the sampling frequency (Samp) and the

method (Method).

Use the Adrrd command to read the Stadr/Enadr value, and the Adrwr command to write the Stadr/Enadr value. In

addition, you need to set up a sampling frequency and an ADPCM algorithm (Method) by using the Rec or Play

command.

The Internal Record/Play Registers

[Note on Issuing the Adrrd or Adrwr command]

In Retroactive Play Mode, multiple phrasing is not allowed by its design. However, the recorded data is processed

as “Phrase = 0” internally. Therefore, be sure to set the second byte to “00h” as you issue the Adrrd or Adrwr

command.

[Note on Issuing the Stadr and Enadr commands]

Sound data has ADPCM intermediate data in each page. By the nature of ADPCM, playback must start from the

top address of a page, otherwise playback cannot be performed properly. Therefore, when you define the Stadr

value with the Adrwr command, be sure to set the lower 7-bit to “0” (i.e. specifying a page’s top address).

Similarly, set the lower 7-bit to “1” when you define the Enadr. (A single page on the DRAM is 1024 bits.)

For the details, see “Storing Sound Data to DRAM (In Blocks)” and “Addressing with the Adrrd and Adrwr

Commands” sections.

Stadr (24 bits)

Enadr (24 bits)

Samp (4 bits)

Method (4 bits)

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