Specifications

VLSI

Solution

VS1053b

VS1053B

8. FUNCTIONAL DESCRIPTION

8.7.2 SCI STATUS (RW)

SCI STATUS contains information on the current status of VS1053b. It also controls some low-level

things that the user does not usually have to care about.

Name Bits Description

SS DO NOT JUMP 15 Header in decode, do not fast forward/rewind

SS SWING 14:12 Set swing to +0 dB, +0.5 dB, .., or +3.5 dB

SS VCM OVERLOAD 11 GBUF overload indicator ’1’ = overload

SS VCM DISABLE 10 GBUF overload detection ’1’ = disable

9:8 reserved

SS VER 7:4 Version

SS APDOWN2 3 Analog driver powerdown

SS APDOWN1 2 Analog internal powerdown

SS AD CLOCK 1 AD clock select, ’0’ = 6 MHz, ’1’ = 3 MHz

SS REFERENCE SEL 0 Reference voltage selection, ’0’ = 1.23 V, ’1’ = 1.65 V

SS DO NOT JUMP is set when WAV, Ogg Vorbis, WMA, MP4, or AAC-ADIF header is being decoded

and jumping to another location in the ﬁle is not allowed.

If AVDD is higher at least 3.3 V, SS REFERENCE SEL can be set to select 1.65 V reference voltage to

increase the analog output swing.

SS AD CLOCK can be set to divide the AD modulator frequency by 2 if XTALI/2 is too much.

SS VER is 0 for VS1001, 1 for VS1011, 2 for VS1002, 3 for VS1003, 4 for VS1053, 5 for VS1033, and

7 for VS1103.

SS APDOWN2 controls analog driver powerdown. SS APDOWN1 controls internal analog powerdown.

These bit are meant to be used by the system ﬁrmware only.

If the user wants to powerdown VS1053b with a minimum power-off transient, set SCI VOL to 0xffff,

then wait for at least a few milliseconds before activating reset.

VS1053b contains GBUF protection circuit which disconnects the GBUF driver when too much current

is drawn, indicating a short-circuit to ground. SS VCM OVERLOAD is high while the overload is

detected. SS VCM DISABLE can be set to disable the protection feature.

SS SWING allows you to go above the 0 dB volume setting. Value 0 is normal mode, 1 gives +0.5 dB,

and 2 gives +1.0 dB. Although the range of the register is upto 7, higher settings than 2 do not work and

should not be used.

Note: Due to a ﬁrmware bug in VS1053b, volume calculation routine clears SS AD CLOCK and

SS REFERENCE SEL bits. Write to SCI STATUS or SCI VOLUME, and sample rate change (if bass

enhancer or treble control are active) causes the volume calculation routine to be called. As a workaround

you can write to SCI STATUS through SCI WRAMADDR and SCI WRAM after each volume change.

Write 0xc001 to SCI WRAMADDR, then write the value to SCI WRAM. However, the difference in

performance between the modes is not signiﬁcant, so it is easier to just use the default mode.

Version 1.01, 2008-05-22 40