and 24 bits formats supported on digital I/O interface.
1.2Control
• Controlled by means of static pins or microcontroller
(L3-bus or I2C-bus) interface.
1.3IEC 60958 input
• On-chip amplifier for converting IEC 60958 input to
CMOS levels
• Supports level I, II and III timing
• Selectable IEC 60958 input channel, one of four
• Supports input frequencies from 28 to 96 kHz
• Lock indication signal available on pin LOCK
• 40 status bits can be read for left and right channel via
L3-bus or I2C-bus
• ChannelstatusbitsavailableviaL3-busorI2C-bus:lock,
pre-emphasis, audio sample frequency, two channel
Pulse Code Modulation (PCM) indication and clock
accuracy
• Pre-emphasis information of incoming IEC 60958
bitstream available in register
• Detection of digital data preamble, such as AC3,
available on pin in microcontroller mode.
1.4IEC 60958 output
• 32, 44.1 and 48 kHz output frequencies (including
double and half of these frequencies) supported in
microcontroller mode
• Via microcontroller, 40 status bits can be set for left and
right channel.
1.5Digital I/O interface
• Supports sampling frequencies from 16 to 100 kHz
• Supported static mode:
–I2S-bus format
– LSB-justified 16 and 24 bits format
– MSB-justified format.
• Supported microcontroller mode:
–I2S-bus format
– LSB-justified 16, 18, 20 or 24 bits format
– MSB-justified format.
• BCKand WS signals can be slave or master,depending
on application mode.
1.6ADC digital sound processing
• Supports sampling frequencies from 16 to 100 kHz
• Analogfront-end includes a 0 to +24 dB PGA in steps of
3 dB, selectable via microcontroller interface
• Digital independent left and right volume control of
+24 to −63.5 dB in steps of 0.5 dB via microcontroller
interface
• Bitstream ADC operating at 64f
• Comb filter decreases sample rate from 64fsto 8f
• Decimator filter (8fsto fs) made of a cascade of three
FIR half-band filters.
s
s
• CMOS output level converted to IEC 60958 output
signal
• Full-swing digital signal, with level II timing using crystal
oscillator clock
• 32, 44.1 and 48 kHz output frequencies supported in
static mode
2003 Apr 103
1.7DAC digital sound processing
• Digital de-emphasis for 32, 44.1, 48 and 96 kHz audio
sampling frequencies
• Automatic de-emphasis when using IEC 60958 to DAC
• Soft mute made of a cosine roll-off circuit selectable via
pin MUTE or L3-bus interface
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
• Programmable digital silence detector
• Interpolating filter (fsto 64fs or fsto 128fs) comprising a
recursive and a FIR filter in cascade
• Selectable fifth-order noise shaper operating at 64fs or
third-order noise shaper operating at 128fs(specially for
low sampling frequencies, e.g. 16 kHz) generating
bitstream for DAC
• Filter Stream DAC (FSDAC)
• In microcontroller mode:
– Left and right volume control (for balance control)
0to−78 dB and −∞
– Left and right bass boost and treble control
– Optional resonant bass boost control
– Mixing possibility of two data streams.
2GENERAL DESCRIPTION
The UDA1355H is a single-chip IEC 60958 decoder and
encoderwith integrated stereo digital-to-analogconverters
and analog-to-digital converters employing bitstream
conversion techniques.
The UDA1355H has a selectable one-of-four SPDIF input
(accepting level I, II and III timing) and one SPDIF output
which can generate level II output signals with CMOS
levels. In microcontroller mode the UDA1355H offers a
large variety of possibilities for defining signal flows
throughtheIC, offering a flexible analog, digital and SPDIF
converter chip with possibilities for off-chip sound
processing via the digital input and output interface.
A lock indicator is available on pin LOCK when the
IEC 60958 decoder and the clock regeneration
mechanism is in lock. By default the DAC output and the
digital data interface output are muted when the decoder
is not in lock.
TheUDA1355H contains two clock systems which can run
at independent frequencies, allowing to lock-on to an
incoming SPDIF or digital audio signal, and in the mean
time generating a stable signal by means of the crystal
oscillator for driving, for example, the ADC or SPDIF
output signal.
Using the crystal oscillator (which requires a 12.288 MHz
crystal) and the on-chip low jitter PLL, all standard audio
sampling frequencies (fs= 32, 44.1 and 48 kHz including
half and double these frequencies) can be generated.
DAC in playback mode−74−mW
DAC in Power-down mode−63−mW
2003 Apr 106
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
5BLOCK DIAGRAM
VOUTL
VOUTR
MUTE
WSO
DATAO
DDA1
V
40
DAC
NOISE
INTER-
42
DAC
SHAPER
POLATOR
BCKO
9
44
8
10
DATA OUT
5
IEC 60958
ENCODER
SPDIFOUT
UDA1355H
41
MGU826
V
V
SSA1
SSE
DDE
V
ndbook, full pagewidth
REF
V
DDI
V
CLK_OUT
DDA2
V
ADCP
V
SSX
V
DDX
V
3237273863911
15
12
TIMING
CLOCK AND
XTAL
13
14
AUDIO
AUDIO
ADC
34
FEATURE
PROCESSOR
FEATURE
PROCESSOR
DECI-
MATOR
COMB
FILTER
ADC
36
INPUT
16432
AND
OUTPUT
SELECT
DATA IN
3
1
IEC 60958
SLICER
232425
DECODER
26
21224
CONTROL
INTERFACE
MODE2
MODE1
MODE0
Fig.1 Block diagram.
SEL_STATIC
MP2
MP0
SSIS
V
ADCN
V
MP1
SSA2
V
29 30 312017 18 197
333528
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2003 Apr 107
XTALIN
XTALOUT
VINL
VINR
RTCB
RESET
WSI
BCKI
DATAI
SPDIF0
SPDIF1
SPDIF2
SPDIF3
LOCK
SLICER_SEL0
SLICER_SEL1
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
6PINNING
SYMBOLPINPAD
(1)
DESCRIPTION
BCKI1bpt4mtht5vbit clock input (master or slave)
WSI2bpt4mtht5vword select input (master or slave)
DATAI3iptht5vdigital data input
LOCK4op4mcPLL lock indicator output
SPDIFOUT5op4mcSPDIF output
V
V
DDE
SSE
6vddedigital pad supply voltage
7vssedigital pad ground
DATAO8ops5cdigital data output
WSO9bpt4mtht5vword select output (master or slave)
BCKO10bpt4mtht5vbit clock output (master or slave)
CLK_OUT11op4mcclock output; 256f
V
DDX
12vddcocrystal oscillator and PLL supply voltage
or 384f
s
s
XTALIN13apiocrystal oscillator input
XTALOUT14apiocrystal oscillator output
V
SSX
15vsscocrystal oscillator and PLL ground
RESET16ipthdt5vreset input
MODE017apiomode selection input 0 for static mode or microcontroller mode (grounded
2
for I
C-bus)
MODE118bpts5tht5vmode selection input 1 for static mode or AO address input and output for
microcontroller mode
MODE219bpts5tht5vmode selection input 2 for static mode or U_RDY output for microcontroller
mode
SEL_STATIC20apioselection input for static mode, I
2
C-bus mode or L3-bus mode
SLICER_SEL021bpts5tht5vSPDIF slicer selection input 0 for static mode and USER bit output for
microcontroller mode
SLICER_SEL122bpts5tht5vSPDIF slicer selection input 1 for static mode and AC3 preamble detect
output for microcontroller mode
SPDIF023apioSPDIF input 0
SPDIF124apioSPDIF input 1
SPDIF225apioSPDIF input 2
SPDIF326apioSPDIF input 3
V
V
DDI
SSIS
27vddidigital core supply voltage
28vssisdigital core ground
MP029apiomulti-purpose pin 0: frequency select for static mode, not used for
microcontroller mode
MP130iptht5vmulti-purpose pin 1: SFOR1 for static mode, SCL for I2C-bus mode and
L3CLOCK for L3-bus mode
2
MP231iic400kt5vmulti-purpose pin 2: SFOR0 for static mode, SDA for I
C-bus mode and
L3DATA for L3-bus mode
V
ADCP
V
ADCN
32vddcopositive ADC reference voltage
33vssconegative ADC reference voltage
2003 Apr 108
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
SYMBOLPINPAD
(1)
DESCRIPTION
VINL34apioADC left channel input
V
SSA2
35vsscoADC ground
VINR36apioADC right channel input
V
V
V
DDA2
REF
DDA1
37vddcoADC supply voltage
38apioreference voltage for ADC and DAC
39vddcoDAC supply voltage
VOUTL40apioDAC left channel output
V
SSA1
41vsscoDAC ground
VOUTR42apioDAC right channel output
RTCB43ipthdt5vtest control input
MUTE44iipthdt5vDAC mute input
Note
1. See Table 1.
Table 1 Pad description
PADDESCRIPTION
iptht5vinput pad; push-pull; TTL with hysteresis; 5 V tolerant
ipthdt5vinput pad; push-pull; TTL with hysteresis; pull-down; 5 V tolerant
op4mcoutput pad; push-pull; 4 mA output drive; CMOS
ops5coutput pad; push-pull; 5 ns slew rate control; CMOS
bpt4mtht5vbidirectional pad; push-pull input; 3-state output; 4 mA output drive; TTL with hysteresis;
C-bus pad; 400 kHz I2C-bus specification with open drain; 5 V tolerant
apioanalog pad; analog input or output
vddcoanalog supply pad
vsscoanalog ground pad
vddedigital supply pad
vssedigital ground pad
vddidigital core supply pad
vssisdigital core ground pad
2003 Apr 109
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
handbook, full pagewidth
DDA1
REF
V
38
DDA2
V
37
VINR
36
SSA2
V
35
VINL
34
33
32
31
30
29
28
27
26
25
24
23
V
ADCN
V
ADCP
MP2
MP1
MP0
V
SSIS
V
DDI
SPDIF3
SPDIF2
SPDIF1
SPDIF0
BCKI
WSI
DATAI
LOCK
SPDIFOUT
V
DDE
V
SSE
DATAO
WSO
BCKO
CLK_OUT
RTCB
43
42
V
VOUTL
41
40
UDA1355H
V
39
MUTE
44
1
2
3
4
5
6
7
8
9
10
11
SSA1
VOUTR
12
13
14
15
XTALIN
XTALOUT
SSX
V
DDX
V
Fig.2 Pin configuration.
7FUNCTIONAL DESCRIPTION
7.1IC control
The UDA1355H can be controlled either via static pins or
via the microcontroller serial hardware interface being the
I2C-bus with a clock up to 400 kHz or the L3-bus with a
clock up to 2 MHz. It is recommended to use the
microcontroller interface since this gives full access to all
the IC features.
The two microcontroller interfaces only differ in interface
format. The register addresses and features that can be
controlled are identical for L3-bus mode and I2C-bus
mode.
The UDA1355H can operate in three control modes:
• Static mode with limited features
• L3-bus mode with full featuring
• I2C-bus mode with full featuring.
The modes are selected via the 3-level pin SEL_STATIC
according to Table 2.
21
16
17
RESET
MODE0
18
19
MODE2
MODE1
22
20
SEL_STATIC
SLICER_SEL1
SLICER_SEL0
MGU828
Table 2 Control mode selection via pin SEL_STATIC
LEVELMODE
HIGHstatic mode
MIDI2C-bus mode
LOWL3-bus mode
7.2Microcontroller interface
The UDA1355H has a microcontroller interface and all the
sound processing features and system settings can be
controlled by the microcontroller.
The controllable settings are:
• Restoring L3-bus defaults
• Power-on settings for all blocks
• Digital interface input and output formats
• Volume settings for the decimator
• PGA gain settings
2003 Apr 1010
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
• Set two times 40 bits of channel status bits of the SPDIF
output
• Select one of four SPDIF input sources
• Enable digital mixer inside interpolator
• Control mute and mixer volumes of digital mixer
• Selection of filter mode and settings of treble and bass
boost for the interpolator (DAC) section
• Volume settings of interpolator
• Selectionof soft mute via cosine roll-off (only effectivein
L3-bus control mode) and bypass of auto mute
• Selection of de-emphasis
• Enable and control of digital mixer inside interpolator.
The readable settings are:
• Mute status of interpolator
• PLL lock and adaptive lock
• Two times 40 bits of channels status bits of the SPDIF
input signal.
7.3Clock systems
The UDA1355H has two clock systems.
The first system uses an external crystal of 12.288 MHz to
generate the audio related system clocks. Only a crystal
with a frequency of 12.288 MHz is allowed.
The second system is a PLL which locks on the SPDIF or
incoming digital audio signal (e.g. I2S-bus) and recovers
the system clock.
7.3.1CRYSTAL OSCILLATOR CLOCK SYSTEM
The crystal oscillator and the on-chip PLL and divider
circuit can be used to generate internal and external clock
signals related to standard audio sampling frequencies
(such as 32, 44.1 and 48 kHz including half and double of
these frequencies).
The audio frequencies supported in either microcontroller
mode or static mode are given in Table 3.
Table 3 Output frequencies
OUTPUT FREQUENCY
BASIC AUDIO
FREQUENCY
32 kHz256 × 16 kHz
44.1 kHz256 × 22.05 kHz
48 kHz256 × 24 kHz
Remarks:
• If an application mode is selected which does not need
a crystal oscillator, the crystal oscillator cannot be
omitted. The reason is that the interpolator switches to
the crystal clock when an SPDIF input signal is
removed. This switch prevents the noise shaper noise
from moving inside the audio band as the PLL gradually
decreases in frequency.
• If no accurate output frequency is needed, the crystal
can be replaced with a resonator.
• Instead of the crystal, a 12.288 MHz system clock can
be applied to pin XTALIN.
The block diagram of the crystal oscillator and the PLL
circuit is given in Fig.3.
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
7.3.4CLOCK OUTPUT
handbook, halfpage
12.288 MHz
XTALIN
XTALOUT
CLK_OUT
13
CRYSTAL
14
OSCILLATOR
11
L3-bus or I
register setting
256fs or 384fs clock
PLL clock
2
C-bus
UDA1355H
PLL
MODULE
MGU830
Fig.3 Crystal oscillator clock system.
7.3.2PLL CLOCK SYSTEM
The PLL locks on the incoming digital data of the SPDIF or
WS input signal. The PLL recovers the clock from the
SPDIForWSI signal and removes jitter toproduceastable
system clock (see Fig.4).
The UDA1355H has a clock output pin (pin CLK_OUT),
which can be used to drive other audio devices in the
system. In microcontroller mode the output clock is
256fsor 384fs. In static mode the output clock is 256 times
32, 44.1 and 48 kHz.
The source of the output clock is either the crystal
oscillator or the PLL, depending on the selected
application and control mode.
7.4IEC 60958 decoder
The UDA1355H IEC 60958 decoder can selectone of four
SPDIFinputchannels. An on-chip amplifier with hysteresis
amplifies the SPDIF input signal to CMOS level, making it
possible to accept both analog and digital SPDIF signals
(see Fig.5).
handbook, halfpage
23
24
25
26
75 Ω
10 nF
180 pF
SPDIF0
SPDIF1
SPDIF2
SPDIF3
SPDIF0
SPDIF1
SPDIF2
SPDIF3
WSI
select SPDIF source
23
24
25
26
SLICER
2
IEC 60958
DECODER
PLL
UDA1355H
256f
384f
s
or
s
MGU827
Fig.4 PLL clock system.
7.3.3WORD SELECTION DETECTION CIRCUIT
This circuit is clocked by the 12.288 MHz crystal oscillator
clock and generates a Word Selection (WS) detection
signal. If the WS detector does not detect any WS edge,
defined as 7 times LOW and 7 times HIGH, then the
WS detection signal is LOW. This information can be used
tosetthe clock for the noise shaper in theinterpolator.This
will prevent noise shaper noise in the audio band.
UDA1355H
MGU829
Fig.5 IEC 60958 input circuit.
7.4.1AUDIO DATA
From the incoming SPDIF bitstream 24 bits of data for the
left and right channel are extracted.
There is a hard mute (not a cosine roll-off mute) if the
IEC 60958 decoder is out of lock or detects bi-mark phase
encoding violations. The lock indicator and the key
channel status bits are accessible in L3-bus mode.
The UDA1355H supports the following sample
frequencies and data rates, including half and double of
these frequencies:
• fs= 32 kHz; resulting in a data rate of 2.048 Mbit/s
• fs= 44.1 kHz; resulting in a data rate of 2.8224 Mbit/s
• fs= 48 kHz; resulting in a data rate of 3.072 Mbit/s.
2003 Apr 1012
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
7.4.2CHANNEL STATUS AND USER BITS
As well as the data bits there are several IEC 60958 key
channel status bits:
• Pre-emphasis and audio sampling frequency bits
• Two channel PCM indicator bits
• Clock accuracy bits.
In total 40 status bits per channel are recovered from the
incomingIEC 60958bitstream.Thesearereadableviathe
microcontroller interface.
User bits, which can contain a large variety of data, such
asCD text, are output to pin SLICER_SEL0 (see Table 4).
In microcontroller mode this signal contains the raw user
bits extracted from the SPDIF bitstream. Signal U_RDY
gives a pulse on pin MODE2 each time there is a new user
bit available. Both signals can be used by an external
microcontroller to grab and decode the user bits.
Table 4 Signal names in microcontroller mode
PIN NAMESIGNAL NAME
SLICER_SEL0USER
MODE2U_RDY
SLICER_SEL1AC3
7.4.3D
Audio and digital data can be transmitted in the SPDIF
bitstream. The PCM channel status bit should be set to
logic 1 if the SPDIF bitstream is carrying digital data
instead of audio data, but in practice it proves that not all
equipment handles these channel status bits properly.
In the UDA1355H, digital data is detected via bit PCM, or
via the sync bytes as specified by IEC. These sync bytes
are two sync words, F872H and 4E1FH (two subframes)
preceded by four or more subframes filled with zeros.
Signal AC3 is kept HIGH for 4096 frames when the
UDA1355H detects this burst preamble. Signal AC3 is
present on pin SLICER_SEL1 in microcontroller mode
(see Table 4).
IGITAL DATA
7.5IEC 60958 encoder
When using the crystal oscillator clock, the IEC 60958
encoder output is a full-swing digital signal with level II
timing.
When the recovered clock from the PLL is used the
IEC 60958 encoder will function correctly but will not meet
level II timing requirements.
7.5.1S
All user and channel status bits are set to logic 0. This is
default value specified by IEC.
In static mode 0 and 2, the selected SPDIF input channel
can be looped through to pin SPDIFOUT (see Fig.6).
7.5.2MICROCONTROLLER MODE
Two times 40 channel status bits can be set. Default value
for each status bit is logic 0. When setting the channel
status bits, it is possible to set only the left channel status
bits and have the bits copied to the right channel.
The procedure of writing the channel status bits is as
follows:
1. Set bit SPDO_VALID = 0 to prevent immediately
2. Set bit l_r_copy = 1 if the right channel needs the
3. Write the left and right channel status bits.
4. Set bit SPDO_VALID = 1 after writing all channel
In microcontroller modes 2 and 13, the selected SPDIF
input channel can be looped through to pin SPDIFOUT
(see Fig.6).
TATIC MODE
sending the status bits during writing.
same status bits as the left channel or set
bit l_r_copy = 0 if the right channel needs different
status bits to the left channel.
statusbitstotheregister.StartingfromthenextSPDIF
block the IEC 60958 encoder will use the new status
bits.
2003 Apr 1013
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
handbook, full pagewidth
SPDIF0
SPDIF1
SPDIF2
SPDIF3
SPDOUT_SEL1
SPDOUT_SEL0
23
24
25
26
SLICER_SEL[1:0
SLICER
select
SPDIF source
21, 22
]
SPDIF
source
UDA1355H
IEC 60958
DECODER
IEC 60958
ENCODER
Fig.6 Selection options for SPDIF output.
7.6Analog input
7.6.1ADC
The analog input is equipped with a Programmable Gain
Amplifier (PGA) which can be controlled via the
microcontroller interface. The control range is from
0 to 24 dB gain in 3 dB steps independent for the left and
right channels.
In applications in with a 2 V (RMS) input signal, a 12 kΩ
resistor must be used in series with the input of the ADC.
The 12 kΩ resistor forms a voltage divider together with
the internal ADC resistor and ensures that the voltage,
applied to the input of the IC, never exceeds 1 V (RMS).
In the application for a 2 V (RMS) input signal, the PGA
must be set to 0 dB. When a 1 V (RMS) input signal is
applied to the ADC in the same application, the PGA gain
must be set to 6 dB.
An overview of the maximum input voltages allowed with
and without an external resistor and the PGA gain setting
is given in Table 5.
Table 5 Maximum input voltage; VDD=3V
EXTERNAL
RESISTOR
(12 kΩ)
PGA GAIN
SETTING
MAXIMUM
INPUT
VOLTAGE
Present0 dB2 V (RMS)
6 dB1 V (RMS)
Absent0 dB1 V (RMS)
6 dB0.5 V (RMS)
SPDOUT_SEL2
MODE[3:0
17 to 1920
MODE[2:0]SEL_STATIC
]
5
SPDIF OUT
MGU833
7.6.2DECIMATION
Thedecimation from 64fsisperformed in two stages: comb
filter and decimation filter. The first stage realizes a
fourth-order characteristic with a decimation factor
sin x
----------- x
of eight. The second stage consists of three half-band
filters each decimating by a factor of two. Table 6 shows
the characteristics.
Table 6 Decimation filter characteristics
ITEMCONDITIONSVALUE (dB)
Pass-band ripple0 to 0.45f
Stop band>0.55f
Dynamic range0 to 0.45f
Overallgain from ADC
input to digital output
DC; V
note 1
= 0 dB;
I
s
s
s
±0.02
−60
140
−1.16
Note
1. Theoutput is not 0 dB when V
=1VatVDD=3V.
I(rms)
This is because the analog components can spread
over the process. When there is no external resistor,
the −1.16 dB scaling prevents clipping caused by
process mismatch.
In the ADC path there are left and right independent digital
volume controls with a range from +24 to −63.5 dB
and −∞ dB. This volume control is also used as a digital
linear mute that can be used to prevent plops when
powering-up or powering down the ADC front path.
2003 Apr 1014
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
7.6.3DC FILTERING
In the decimator there are two digital DC blocking circuits.
The first blocking circuit is in front of the volume control to
remove DC bias from the ADC output. The DC bias is
added in the ADC to prevent audio band Idle tones
occurring in the noise shaper. With the DC components
removed, a signal gain of 24 dB can be achieved.
The second blocking circuit removes the DC components
introduced by the decimator stage.
7.6.4OVERLOAD DETECTION
Bit OVERFLOW = 1 when the output data in the left or
right channel is larger than −1.16 dB of the maximum
possible digital swing. This condition is set for at least
512fs cycles (that is 11.6 ms at fs= 44.1 kHz). This
time-out is reset for each infringement.
7.7Analog output
7.7.1AUDIO FEATURE PROCESSOR
The audio feature processor provides automatic
de-emphasis for the IEC 60958 bitstream.
In microcontroller mode all features are available and
there is a default mute on start up.
7.7.2INTERPOLATING FILTER
The digital filter interpolates from 1fsto 64fs, or from
1fsto 128fs, by cascading a half-band filter and a FIR filter.
The stereo interpolator has the following basic features:
• 24-bit data path
• Mixing of two channels:
– To prevent clipping inside the core, there is an
automatic signal level correction of −6 dB scaling
before mixing and +6 dB gain after digital volume
control
– Position of mixing can be set before or after bass
boost and treble
– Mastervolume control andmutewithindependent left
and right channel settings for balance control
– Independently left and right channel de-emphasis,
volume control and mute (no left or right)
– Output of the mixer is to the I2S-bus or IEC 60958
decoder.
• Full FIR filter implementation for all the upsampling
filters
• Integrated digital silence detection for left and right
channels with selectable silence detection time
• Support for 1fsand 2fs input data rate and 192 kHz
audio via I2S-bus.
The stereo interpolator has the following sound features:
• Linear volume control using 14-bit coefficients with
0.25 dB steps: range 0 to −78 dB and −∞ dB; hold for
master volume and mixing volume control
• A cosine roll-off soft mute with 32 coefficients; each
coefficientis used for four samples, in total 128 samples
are needed to fully mute or de-mute (approximately
3 ms at fs= 44.1 kHz)
• Independent selectable de-emphasis for 32, 44.1, 48
and 96 kHz for both channels
• Treble is the selectable positive gain for high
frequencies. The edge frequency of the treble is fixed
and depends on the sampling frequency. Treble can be
set independently for left and right channel with two
settings:
–fc= 1.5 kHz; fs= 44.1 kHz; 0 to 6 dB gain range with
2 dB steps
–fc= 3 kHz; fs= 44.1 kHz; 0 to 6 dB gain range with
2 dB steps.
• Normal bass boost is the selectable positive gain for low
frequencies. The edge frequency of the bass boost is
fixed and depends on the sampling frequency. Normal
bassboostcan be set independently for the left and right
channel with two sets:
–fc= 250 Hz;fs= 44.1 kHz;0 to 18 dBgainrangewith
2 dB steps
–fc= 300 Hz;fs= 44.1 kHz;0 to 24 dBgainrangewith
2 dB steps.
• Resonant bass boost optional function is selected if
bit BASS_SEL = 1. When selected, the characteristics
aredeterminedbysix14-bitcoefficients.Resonantbass
boost controls the left and right channel with the same
characteristics. When resonant bass boost is selected,
the treble control also changes to a single control for
both channels following the gain setting of the left
channel.
Asoftware program is available foruserstogenerate the
required six 14-bit coefficients by entering the desired
centre frequency (fc), positive or negative peak gain,
sampling frequency (fs) and shape factor (see
Figs 7 and 8).
2003 Apr 1015
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
Table 7 Interpolation filter characteristics
ITEMCONDITIONSVALUE (dB)
Pass-band ripple0 to 0.45f
Stop band>0.55f
Dynamic range0 to 0.4535f
7.7.3D
IGITAL MIXER
s
s
s
±0.035
−60
140
The UDA1355H has a digital mixer inside the interpolator.
Thedigitalmixer can be used as a cross over or a selector.
A functional block diagram of the mixer mode is shown in
Fig.9. This mixer can be used in microcontroller mode
only.
The UDA1355H can be set to the mixer mode by setting
bit MIX = 1.In the mixer mode, there are three volume and
10
handbook, halfpage
gain
8
(dB)
6
4
2
0
−2
−4
−6
−8
−10
11010
MGU832
2103
f (Hz))
mute controls available: for source 1, for source 2 and for
the master (sum) signal. All three volume ranges can be
controlled in 0.25 dB steps.
Topreventclipping inside the mixer, the signals are scaled
with −6 dB before mixing, therefore the sum of the two
signals is always equal to or lower than 0 dB. After the
mixing there is a 6 dB gain in the master volume control.
This means that at the analog output the signal can clip,
but the clipping can be undone by decreasing the master
volume control.
2
The output of the mixer is available via the I
S-bus output
or via the SPDIF output. The output signal of the mixer is
scaled to a maximum of 0 dB, so the digital output can
never clip.
10
handbook, halfpage
gain
8
(dB)
6
4
2
0
−2
−4
−6
−8
−10
11010
MGU831
2103
f (Hz))
fc=70Hz
fs= 44.1 kHz
Peak gain = 10 dB
Shape factor = 1.4142
Fig.7 Resonant bass boost example 1.
2003 Apr 1016
fc=70Hz
fs= 44.1 kHz
Peak gain = 10 dB
Shape factor = 1.4142
Fig.8 Resonant bass boost example 2.
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
handbook, full pagewidth
channel 2
VOLUME
DE-EMPHASIS
VOLUME
DE-EMPHASIS
channel 1
AND
MUTE
AND
MUTE
mixing before
sound features
BASS-BOOST
AND
TREBLE
Fig.9 Digital mixer (DAC) inside the interpolator DSP.
7.7.4DIGITAL SILENCE DETECTOR
The UDA1355H is equipped with adigital silence detector.
This detects whether a certain amount of consecutive
samples are 0. The number of samples can be set with
bits SD_VALUE[1:0] to 3200, 4800, 9600 or 19600
samples.
The digital silence detection status can be read via the
microcontroller interface.
7.7.5NOISE SHAPER (DAC)
The noise shaper shifts in-band quantization noise to
frequencies above the audio band. The noise shaper
output is converted into an analog signal using a Filter
Stream Digital-to-Analog Converter (FSDAC). This noise
shaping technique enables high signal-to-noise ratios to
be achieved.
The UDA1355H is equipped with two noise shapers:
• A third-order noise shaper operating at 128fs. Which is
used at low sampling frequencies (8 to 16 kHz) to
prevent noise shaper noise shifting into the audio band
for the fifth-order noise shaper
• A fifth-order noise shaper operating at 64fs. Which is
used at high sampling frequencies (from 32 kHz
upwards).
When the noise shaper changes, the clock to the FSDAC
changes and the filter characteristic of the FSDAC also
changes. The effect on the roll of is compensated by
selecting the filter matching speed and order of the noise
shaper.
mixing after
sound features
1f
s
output of mixer
L3/I
2
C bit
FILTER
INT.
UDA1355H
MASTER
2f
s
VOLUME
AND
MUTE
to
interpolation
filter and
DAC output
MGU834
7.7.6FILTER STREAM DAC
The FSDAC is a semi digital reconstruction filter that
converts the 1-bit data bitstream of the noise shaper to an
analog output voltage. The filter coefficients are
implemented as current sources and are summed at
virtual ground of the operational amplifier output. In this
way, very high signal-to-noise performance and low clock
jitter sensitivity are achieved. A post filter is not needed
due to the inherent filter function of the FSDAC. On-chip
amplifiers convert the FSDAC output current to an output
voltage signal capable of driving a line output. The output
voltageoftheFSDAC scales proportionally with the supply
voltage.
7.7.7DAC MUTE
The DAC and interpolator can be muted by setting
pin MUTE to a HIGH level. The output signal is muted to
zero via a cosine roll-off curve and the DAC is powered
down. When pin MUTE is at LOW level the signal rise
follows the same cosine curve.
To prevent plops in case of changing inputs, clock to the
DAC or application modes, a special mute circuit for the
DAC is implemented (see Table 8).
In all application modes in which the DAC is active the
DAC can be muted by pin MUTE. The microcontroller
mute bits and pin MUTE act as an OR function.
2003 Apr 1017
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
Table 8 Muting to prevent plopping
OCCASION
MT1MT2MTM
Input selection
Select channel 1 sourcex−−no mute after selection
Select channel 2 source−x−no mute after selection
Select chip mode
PLL is source for the DAC−−xwait until PLL is locked again
Crystal is source for the DAC−−xno mute after selection
Select between microcontroller mode and static mode
PLL is source for the DAC−−xwait until PLL is locked again
Crystal is source for the DAC−−xno mute after selection
Audio features
Select noise shaper order−−xno mute after selection
Select FSDAC output polarity−−xno mute after selection
Select SPDIF input−−xPLL is locked again
Select mixer−−−no mute needed
Select mixer position−−−no mute needed
Select crystal clock source−−xno mute after selection
BIT
DE-MUTE CONDITION
7.8Digital audio input and output
The selection of the digital audio input and output formats
and master or slave modes differ for static and
microcontroller mode.
In master mode, when 256fs output clock is selected and
the digital interface is master, the BCK output clock will be
64fs.Incase384fsoutputclockisselected,theBCK output
clock will be 48fs.
In the static mode the digital audio input formats are:
• I2S-bus
• LSB-justified; 16 bits
• LSB-justified; 24 bits
• MSB-justified.
The digital audio output formats are:
• I2S-bus
• MSB-justified.
In the microcontroller mode, the following formats are
independently selectable:
• I2S-bus
• LSB-justified; 16 bits
• LSB-justified; 18 bits
• LSB-justified; 20 bits
• LSB-justified; 24 bits
• MSB-justified.
7.9Power-on reset
The UDA1355H has a dedicated reset pin with an internal
pull-down resistor. In this way a Power-on reset circuit can
bemadewithacapacitorandaresistoratpin RESET.The
external resistor is needed since the pad is 5 V tolerant.
This means that there is a transmission gate in series with
the input and the resistor inside the pad cannot be seen
from the outside world (see Fig.10).
The reset timing is determined by the external pull-down
resistor and the external capacitor which is connected to
pin RESET. At Power-on reset, all the digital sound
processing features and the system controlling features
are set to the default setting of the microcontroller mode.
Since the bit controlling the clock of the synchronous
registers is set to enable, the synchronous registers are
also reset.
2003 Apr 1018
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
8APPLICATION MODES
handbook, halfpage
RESET
Transmission gate
for 5V tolerance
16
UDA1355H
V
SS
MGU835
Fig.10 5 V tolerant pull-down input pad.
The clock should be running during the reset time. When
noclockcanbe guaranteed in microcontroller mode, a soft
reset should be given when the system is running by
writing to register 7FH.
Table 9 Static mode pin assignment
In this chapter the application modes for static mode and
microcontroller mode are described.
The UDA1355H can be controlled by static pins, the
L3-busorI2C-businterface.Duetothelimitationsimposed
bythe pin count, only basic functions are available in static
mode. For optimum use of the UDA1355H features, the
microcontroller mode is strongly recommended.
There are 11 application modes available in the static
mode and 14 application modes in microcontroller mode.
The application modes are explained in the two sections:
Section 8.2 explains the application modes 0 to 10.
Section 8.4 explains the more advanced features of
modes 0 to 10 and modes 12 to 14 available in the
microcontroller mode.
8.1Static mode pin assignment
The default values for all non-pin controlled settings are
identical to the start-up defaults from the microcontroller
mode.WhetherBCK and WS are master or slave depends
on the selected application mode.
Table 9 defines the pin functions in static mode.
PIN
STATIC MODE
SYMBOL
LEVELDESCRIPTION
4LOCKLOWIEC 60958 decoder out of lock (when SPDIF input) or clock
regeneration out of lock (I
2
S-bus input)
HIGHIEC 60958 decoder in lock (when SPDIF input) or clock
regeneration in lock (I
2
S-bus input)
16RESETLOWnormal operation
HIGHreset
17, 18,19MODE0, MODE1,
−select application mode; see Table 10
MODE2
20SEL_STATICHIGHstatic pin control
LOWmicrocontroller mode
22, 21SLICER_SEL1,
SLICER_SEL0
LOW, LOWIEC 60958 input from pin SPDIF0
LOW, HIGHIEC 60958 input from pin SPDIF1
HIGH, LOWIEC 60958 input from pin SPDIF2
HIGH, HIGHIEC 60958 input from pin SPDIF3
29FREQ_SELLOWselect 44.1 kHz sampling frequency for the crystal oscillator,
note 1
MIDselect 32 kHz sampling frequency for the crystal oscillator, note 1
HIGHselect 48 kHz sampling frequency for the crystal oscillator, note 1
2003 Apr 1019
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
PIN
30, 31SFOR1, SFOR0LOW, LOWset I
STATIC MODE
SYMBOL
LEVELDESCRIPTION
2
S-bus format for digital data input and output interface
LOW, HIGHset LSB-justified 16 bits format for digital data input interface and
MSB-justified format for digital data output interface
HIGH, LOWset LSB-justified 24 bits format for digital data input interface and
MSB-justified format for digital data output interface
HIGH, HIGHset MSB-justified format for digital data input and output interface
44MUTELOWnormal operation
HIGHmute active
Note
1. FPLL 256fs is output from pin CLKOUT in PLL locked static mode.
8.2Static mode basic applications
The static application modes are selected with the pins MODE2, MODE1 and MODE0, with pin MODE0 being a 3-level
pin. In Table 10, the encoding of the pins MODE[2:0] is given.
Table 10 Static mode basic applications
MODE
MODE SELECTION PINS
(1)
MODE2MODE1MODE0
SPDIF
INPUT
SPDIF
OUTPUT
CLOCK
ADCDAC
(2)
I2S-BUS
INPUT
SLAVE
I2S-BUS
OUTPUT
MASTER
PLL
LOCKS
ON
INPUT
0LLLPLLPLL−PLL−PLLSPDIF
1L L M − PLL−PLLPLL−I2S-bus
2LLHPLLPLL−PLLPLLPLLSPDIF
3L H L − xtalxtal−−xtal−
4L H M − xtalxtalxtalxtalxtal−
5L H H − xtalxtalxtalxtalxtal−
6H L L − PLLxtalPLLPLLxtalI
2
S-bus
7HLMPLLxtalxtalPLL−xtalSPDIF
8H L H − xtalxtalPLLPLLxtalI2S-bus
9HHLPLLxtal−xtalxtalPLLSPDIF
10HHMPLLxtal−PLLxtalPLLSPDIF
11HHHnot used
Notes
1. In column mode selection pins means:
L: pin at 0 V; M: pin at half V
; H: pin at V
DDD
DDD
.
2. In column clock means:
xtal: the clock is based on the crystal oscillator; PLL: the clock is based on the PLL.
2003 Apr 1020
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
The first 11 application modes are given in this section. Schematic diagrams of these application modes are given in
Table 11. In this table the basic features are mentioned and also the extra features in case of microcontroller mode are
given. It should be noted that the blocks running at the crystal clock (XTAL) are marked unshaded while the blocks
running at the PLL clock are shaded.
Table 11 Overview of static mode basic applications
MODEFEATURESSCHEMATIC
0Data path:
2
• Input SPDIF to outputs DAC, I
SPDIFOUT via loop through.
Features:
• System locks onto the SPDIF input
signal
• BCK and WS are master
• Microcontroller mode:
– DAC sound features can be used
– SPDIF input channel status bits
(two times 40 bits) can be read.
S or
SPDIF IN
SPDIF LOCK
PLL
MUTE
DAC
SPDIFOUT
I2S OUTPUTI2S master
MGU836
1Data path:
• Input I
(level II not guaranteed: depends on
I2S-bus clock).
Features:
• System locks onto the WSI signal
• BCKI and WSI are slave
• Microcontroller mode:
– DAC sound features can be used
– SPDIF output channel status bits
(two times 40 bits) setting.
2
S to outputs DAC or SPDIF
I2S slave
I2S INPUT
PLL
I2S LOCK
MUTE
DAC
SPDIF OUT
MGU837
2003 Apr 1021
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
MODEFEATURESSCHEMATIC
2Data path:
• Input SPDIF to outputs I
SPDIFOUT via loop through
• Input I2S to output DAC.
Features:
• Possibility to process input SPDIF via
2
S-bus using an external DSP and
I
then to output DAC
• System locks onto the SPDIF input
signal
• I2S input and output with BCK and WS
are master
• Microcontroller mode: see Section 8.4.
2
S or
SPDIF IN
I2S INPUT
I2S slave
EXTERNAL DSP
(e.g. equalizing, spatializing)
(SAA7715)
PLL
I2S OUTPUT
SPDIF LOCK
DAC
2
S master
I
MGU838
MUTE
SPDIFOUT
3Data path:
• Input ADC to outputs I
Features:
• Crystal oscillator generates the clocks
• Microcontroller mode:
– PGA gain setting
– Volume control in decimator setting
– SPDIF output channel status bits
(two times 40 bits) setting.
4Data path:
• Input ADC to output I
• Input I2S to outputs DAC or SPDIF.
Features:
• Possibility to process input ADC via
2
S-bus using a external DSP and then
I
to outputs DAC or SPDIF
• Crystal oscillator generates the clocks
• I2S input and output with BCK and WS
are master
• Microcontroller mode: see Section 8.4.
2
S or SPDIF.
2
S
ADC
ADC
I
2
XTAL
XTAL
S INPUT
I2S slave
EXTERNAL DSP
(e.g. equalizing, spatializing)
(SAA7715)
SPDIF OUT
I2S OUTPUT
MGU839
DAC
SPDIF OUT
2
I
S OUTPUT
I2S master
MGU840
I2S master
MUTE
2003 Apr 1022
Philips SemiconductorsPreliminary specification
Stereo audio codec with SPDIF interfaceUDA1355H
MODEFEATURESSCHEMATIC
5Data path:
• Input ADC to outputs I
• Input I2S to output DAC.
Features:
• Possibility to process input ADC via
2
I
S-bus using an external DSP and
then to output DAC
• Crystal oscillator generates the clocks
• I2S input and output with BCK and WS
are master
• Microcontroller mode: see Section 8.4.
2
S or SPDIF
XTAL
ADC
2
I
S INPUT
I2S slave
EXTERNAL DSP
(e.g. equalizing, spatializing)
(SAA7715)
DAC
SPDIF OUT
2
I
S OUTPUT
I2S master
MGU841
MUTE
6Data path:
• Input ADC to output I
• Input I2S to outputs DAC or SPDIF
(level II not guaranteed: depends on
I2S-bus clock).
Features:
• Possibility to process input ADC via
2
I
S-bus using an external DSP and
then to outputs DAC or SPDIF
• Crystal oscillator generates the clocks
for input ADC and output I2S
• WSI is slave
• WSO is master
• Microcontroller mode: see Section 8.4.
2
S
I2S LOCK
XTAL
I2S INPUT
I2S slave
EXTERNAL DSP
(SAA7715)
PLL
SPDIF OUT
I
DACADC
2
S OUTPUT
I2S master
MGU842
MUTE
2003 Apr 1023
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