LM4549BVHX/NOPB National Semiconductor, LM4549BVHX/NOPB Datasheet - Page 22

• Manufacturer Part Number: LM4549BVHX/NOPB
• Description: IC AUDIO CODEC 2MULTICH 48-LQFP
• Manufacturer: National Semiconductor
• Type: Audio Codec '97r

Specifications of LM4549BVHX/NOPB

• Data Interface: Serial
• Resolution (bits): 18 b
• Number Of Adcs / Dacs: 2 / 2
• Sigma Delta: Yes
• Dynamic Range, Adcs / Dacs (db) Typ: 90 / 89
• Voltage - Supply, Analog: 4.2 V ~ 5.5 V
• Voltage - Supply, Digital: 3.3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM4549BVHX

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Register Descriptions
Default settings are indicated by *.
RESET REGISTER (00h)
Writing any value to this register causes a Register Reset
which changes all registers back to their default values. If a
read is performed on this register, the LM4549B will return a
value of 0D40h. This value can be interpreted in accordance
with the AC ’97 Specification to indicate that National 3D
Sound is implemented and 18-bit data is supported for both
the ADCs and DACs.
MASTER VOLUME REGISTER (02h)
This output register allows the output level from either chan-
nel of the stereo LINE_OUT to be muted or attenuated over
the range 0 dB – 46.5 dB in nominal 1.5 dB steps. There are
6 bits of volume control for each channel and both stereo
channels can be individually attenuated. The mute bit (D15)
acts simultaneously on both stereo channels of LINE_OUT.
The AC’97 specification states that “support for the MSB of
the level is optional.” All six bits may be written to the
register, but if the MSB is a ’1’, the MSB is ignored and the
register will be set to 0 11111. This will be the value when the
register is read, allowing the software driver to detect
whether the MSB is supported or not.
LINE LEVEL VOLUME REGISTER (04h)
This output register allows the level from both channels of
LNLVL_OUT to be muted or individually attenuated over the
range 0 dB to –46.5 dB in nominal 1.5 dB steps. There are 6
bits of volume control for each channel plus one mute bit.
The mute bit (D15) acts on both channels. Operation of this
register and LNLVL_OUT matches that of the Master Volume
register and the LINE_OUT output.
MONO VOLUME REGISTER (06h)
This output register allows the level from MONO_OUT to be
muted or attenuated over the range 0 dB – 46.5 dB in
nominal 1.5 dB steps. There are 6 bits of volume control and
one mute bit (D15). All six bits may be written to the register,
but if the MSB is a 1, the MSB is ignored and the register will
be set to 0 11111. This will be the value when the register is
read, allowing the software driver to detect whether the MSB
is supported or not.
Default: 8000h
Default: 8000h
Mute
Mute
0
0
0
0
1
0
0
0
0
1
MM5:MM0
X XXXXX
X XXXXX
Mx5:Mx0
0 00000
0 00000
0 11111
1 xxxxx
0 11111
0 11111
1 xxxxx
0 11111
0 dB attenuation
46.5 dB attenuation
As Written
As read back
*mute
0 dB attenuation
46.5 dB attenuation
As written
As read back
*mute
Function
Function
22
PC BEEP VOLUME REGISTER (0Ah)
This input register adjusts the level of the mono PC_BEEP
input to the stereo mixer MIX2 where it is summed equally
into both channels of the Stereo Mix signal. PC_BEEP can
be both muted and attenuated over a range of 0 dB to –45
dB in nominal 3 dB steps. Note that the default setting for the
PC_Beep Volume register is 0 dB attenuation rather than
mute.
MIXER INPUT VOLUME REGISTERS (Index 0Ch - 18h)
These input registers adjust the volume levels into the stereo
mixers MIX1 and MIX2. Each channel may be adjusted over
a range of +12 dB gain to –34.5 dB attenuation in 1.5 dB
steps. For stereo ports, volumes of the left and right chan-
nels can be independently adjusted. Muting a given port is
accomplished by setting the MSB to 1. Setting the MSB to 1
for stereo ports mutes both the left and right channels. The
Mic Volume register (0Eh) controls an additional 20 dB boost
for the selected microphone input by setting the 20dB bit
(D6).
RECORD SELECT REGISTER (1Ah)
This register independently controls the sources for the right
and left channels of the stereo ADC. The default value of
0000h corresponds to selecting the (mono) Mic input for both
channels.
Default: 0000h
Default:
SR2:SR0
SL2:SL0
Mute
Mute
0
0
1
0
0
0
1
0
1
2
3
4
5
6
7
0
1
2
3
4
5
8008h (mono registers)
8808h (stereo registers)
PV3:PV0
Gx4:Gx0
X XXXX
0 0000
0 1000
1 1111
XXXX
0000
1111
Source for Right Channel ADC
Source for Left Channel ADC
*Mic input
CD input (L)
VIDEO input (L)
AUX input (L)
LINE_IN input (L)
Stereo Mix (L)
Mono Mix
PHONE input
*Mic input
CD input (R)
VIDEO input (R)
AUX input (R)
LINE_IN input (R)
Stereo Mix (R)
*0 dB attenuation
45 dB attenuation
mute
+12 dB gain
0 dB gain
*mute
–34.5 dB attenuation
Function
Function