
3.3.1 - Reset Register
(index 00h)
Writing any value to this register performs a register
reset, which causes all registers to revert to their
default values. Reading this register returns the ID
code for the part and the code for the type of 3D
Stereo Enhancement supported.
All DACs operate at the same resolution. All ADCs
operate at the same resolution.
bit = 1
ID0
ID1
ID2
ID3
ID4
ID5
ID6
ID7
ID8
ID9
Function
Value
0
0
1
0
0
0
0
0
0
0
Dedicated Mic PCM in channel
Modem Line Codec support
Bass&Treble control
Simulated Stereo (Mono to Stereo)
Headphone output support
Loudness (bass boost) support
18-bit DAC resolution
20-bit DAC resolution
18-bit ADC resolution
20-bit ADC resolution
For ST7597 a read of the 3D control register will
return 0800h.
SE4..SE0
00000
00001
00010
Function
Value
No 3D stereo enhancement
Analog devices 3D stereo enhancement
Creative labs 3D stereo enhancement
National Semiconductor
3D stereo enhancement
Yamaha 3D stereo enhancement
BBE 3D stereo enhancement
Crystal Semiconductor
3D stereo enhancement
Q-sound QX (stereo enhancement)
Spatialized (stereo enhancement)
SRS (stereo enhancement)
00000
00011
00100
00101
00110
00111
01000
01001
3.3.2 - Play Master Volume Registers
(index 02h and 06h)
These registers manage manage the output signal
volumes. Register 02h controls the stereo master
volume (both right and left channels). Register 06h
controls the mono volume output. Each step corre-
sponds to 1.5dB. The MSB of the register is the
mute bit. When this bit is set to 1 the level for that
channel is set to <-80dB. ML5 through ML0 is for
the left channel level, MR5 through MR0 is for the
right channel and MM5 through MM0 is for the
mono out channel.
The MSB of the level is not supported by this
version of ST7597. When the MSB is set to 1 then
the ST7597 will set the 5 LSBs to 1. Example: if the
driver writes a 1xxxxx, the ST7597 will interpret that
as x11111. It will also respond when read with
x11111 rather than 1xxxxx, the value written to it.
The driver can use this feature to detect if the 6th
bit is there or nor.
The default value is 8000h, which corresponds to
0dB attenuation with mute on.
Mute
0
0
0
1
Mx5..Mx0
00 0000
01 1111
1x xxxx
xx xxxx
Function
0dB attenuation
46.5dB attenuation
46.5dB attenuation
<-80dB gain
3.3.3 - Master Tone Control Register
(index 08h)
A tone function (treble-bass) is available in this
chip, to use this function four external capacitors
have to be used and have to be connected to the
six pins provided (see block diagram/pinout/list of
external components).
The characteristics of this function are described
herebelow.
TR3..TR0
BA3..BA0
Gain/Attenuation in dB
0000
+10.5
0001
+09.0
0010
+07.5
0011
+06.0
0100
+04.5
0101
+03.0
0110
+01.5
0111
00.0
1000
-01.5
1001
-03.0
1010
-04.5
1011
-06.0
1100
-07.5
1101
-09.0
1110
-10.5
1111
bypass (default)
The default value is 0F0Fh, which corresponds to
Bypass of Bass and Treble gain.
FUNCTIONAL DESCRIPTION
(continued)
ST7597
13/20