Datasheet

VS1053b Datasheet
9 FUNCTIONAL DESCRIPTION
9.6.10 SCI_AIADDR (RW)
SCI_AIADDR indicates the start address of the application code written earlier with SCI_WRAMADDR
and SCI_WRAM registers. If no application code is used, this register should not be initialized,
or it should be initialized to zero. For more details, see Application Notes for VS10XX.
Note: Reading AIADDR is not recommended. It can cause samplerate to be set to a very low
value.
9.6.11 SCI_VOL (RW)
SCI_VOL is a volume control for the player hardware. The most significant byte of the volume
register controls the left channel volume, the low part controls the right channel volume. The
channel volume sets the attenuation from the maximum volume level in 0.5 dB steps. Thus,
maximum volume is 0x0000 and total silence is 0xFEFE.
Note, that after hardware reset the volume is set to full volume. Resetting the software does
not reset the volume setting.
Setting SCI_VOL to 0xFFFF will activate analog powerdown mode.
Example: for a volume of -2.0 dB for the left channel and -3.5 dB for the right channel: (2.0/0.5)
= 4, 3.5/0.5 = 7 → SCI_VOL = 0x0407.
Example: SCI_VOL = 0x2424 → both left and right volumes are 0x24 * -0.5 = -18.0 dB
In VS1053b bass and treble initialization and volume change is delayed until the next batch of
samples are sent to the audio FIFO. Thus, audio interrupts can no longer be missed during a
write to SCI_BASS or SCI_VOL.
This delays the volume setting slightly, but because the volume control is now done in the DAC
hardware instead of performing it to the samples going into the audio FIFO, the overall volume
change response is better than before. Also, the actual volume control has zero-cross detec-
tion, which almost completely removes all audible noise that occurs when volume is suddenly
changed.
9.6.12 SCI_AICTRL[x] (RW)
SCI_AICTRL[x] registers ( x=[0 .. 3] ) can be used to access the user’s application program.
The AICTRL registers are also used with PCM/ADPCM encoding mode.
Version: 1.22, 2014-12-19 47