Datasheet

VS1053B OGG VORBIS ENCODER VSMPG

2.3.2 Loading and Starting the Code

To load and start the VS1053b Ogg Vorbis Encoder, do the following steps:

1. Set the VS1053b clock to the highest value just below 55.3 MHz. Example: if the

external clock is 12.288 MHz, this can be done by setting the clock to 4.5X, or

55.296 MHz by writing 0xC000 to register SCI_CLOCKF (3). If you use another

input clock, adjust SCI_CLOCKF accordingly.

Examples: Value for 12 MHz is 0xC3e8, 12.288 MHz is 0xC000, 13 MHz is 0xA4E2.

2. Set SCI_BASS (2) to 0.

3. Reset VS1053b by setting bit SM_RESET (2) to 1 in register SCI_MODE (0). At

the same time, clear bit SM_ADPCM (12) to 0. Remember that resetting takes

time, so don’t do any ﬁrther register writes before the DREQ pin has risen!

4. Disable all interrupts except the SCI interrupt by writing 0x2 to VS1053’s internal

(7), then 0x2 to SCI_WRAM (6).

5. Load the plugin proﬁle you intend to run (Chapter 4). Note that you will have to

redo this each time you want to activate recording.

6. Set bit SM_ADPCM (12) in register SCI_MODE (0) to 1. At the same time, you

can also select LINE input instead of MIC input by setting bit SM_LINE1 (14) to 1.

If you want to use the VU meter in stereo mode, set also bit SM_LAYER12 (1) to

1. Do not set SM_RESET (2) at the same time!

7. Set recording level control registers SCI_AICTRL1 (13) and SCI_AICTRL2 (14).

Typical good values for conservative AGC are 0 and 4096, respectively. For a HiFi

application, recommended values are 1024 and 0, respectively.

8. If you want to use a VU meter, write 0x8000 to SCI_AICTRL0 (12) if using a mono

proﬁle or 0x8080 is using a stereo proﬁle.

9. Set a proper value (often 0) to SCI_AICTRL3 (15).

10. If you use a proﬁle that support Vox, set Vox registers. For details, see Chapter 2.5.

11. Activate the encoder by writing 0x34 to register SCI_AIADDR (10).

12. Wait until DREQ pin is high before reading any data.

Rev. 1.70c 2012-11-16

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