Copyright Cirrus Logic, Inc. 2012
(All Rights Reserved)
http://www.cirrus.com
192 kHz Digital Audio Interface Transmitter
Features
Complete EIAJ CP1201, IEC-60958, AES3,
S/PDIF-compatible Transmitter
+3.3 V or 5.0 V Digital Supply (VD)
+3.3 V or 5.0 V Digital Interface (VL)
On-Chip Channel Status and User Bit Buffer
Memories Allow Block-Sized Updates
Flexible 3-Wire Serial Digital Audio Input Port
Up to 192-kHz Frame Rate
Microcontroller Write Access to Channel Status
and User Bit Data
On-Chip Differential Line Driver
Generates CRC Codes and Parity Bits
Stand-Alone Mode Allows Use without a
Microcontroller
General Description
The CS8406 is a monolithic CMOS device which en-
codes and transmits audio data according to the AES3,
IEC60958, S/PDIF, o r EIAJ CP1201 standards. The
CS8406 accepts aud io and digital data, which is then
multiplexed, encoded, and driven onto a cable.
The audio data is input through a configurable, 3-wire
input port. The channel status and user bit data are in-
put through an SPI™ or I²C® microcontroller port, and
may be assembled in block-sized buffers. For systems
with no microcontroller, a Stand-Alone Mode allows di-
rect access to channel status and user bit data pins.
The CS8406 is available in a 28-pin TSSOP and SOIC
package for both Co mmercial (-10º to +70ºC) and
Automotive grade (-40º to +85ºC). The CDB8416
Demonstration board is also available for device
evaluation and implementation suggestions. Please
refer to “Ordering Information” on page 34 for complete
details.
Target applications include A/V Receivers, CD-R, DVD
receivers, digital mixin g consoles, effects processors,
set-top boxes, and computer and automotive audio
systems.
RXP
ILRCK
ISCLK
SDIN
TXP
TXN
RST OMCK
USDA/
CDOUT
SCL/
CCLK
AD1/
CDIN
AD0/
CS
INT
VL GND
AD2H/S
VD
TCBL
Misc.
Control
Serial
Audio
Input
C or U Data Buffer
Control Port &
Registers
AES3
S/PDIF
Encoder
Output Clock
Generator
Driver
AUG '12
DS580F6
CS8406
2DS580F6
CS8406
TABLE OF CONTENTS
1. CHARACTERISTICS AND SPECIFICATIONS ..................................................................................... 4
SPECIFIED OPERATING CONDITIONS .............................................................................................. 4
ABSOLUTE MAXIMUM RATINGS ........................................................................................................4
DC ELECTRICAL CHARACTERISTICS ............................................................................................... 4
DIGITAL INPUT CHARACTERISTICS .................................................................................................. 5
DIGITAL INTERFACE SPECIFICATIONS ............................................................................................ 5
TRANSMITTER CHARACTERISTICS .................................................................................................. 5
SWITCHING CHARACTERISTICS .......................................................................................................5
SWITCHING CHARACTERISTICS - SERIAL AUDIO PORTS ............................................................. 6
SWITCHING CHARACTERISTICS - CONTROL PORT - SPI MODE................................................... 7
SWITCHING CHARACTERISTICS - CONTROL PORT - I²C MODE.................................................... 8
2. TYPICAL CONNECTION DIAGRAMS .................................................................................................. 9
3. GENERAL DESCRIPTION .................................................................................................................. 11
3.1 AES3 and S/PDIF Standards Documents .................................................................................... 11
4. THREE-WIRE SERIAL INPUT AUDIO PORT ..................................................................................... 12
5. AES3 TRANSMITTER ......................................................................................................................... 13
5.1 TXN and TXP Drivers ................................................................................................................... 13
5.2 Mono Mode Operation .................................................................................................................. 13
5.3 Transmitted Frame and Channel Status Boundary Timing ........................................................... 13
6. CONTROL PORT DESCRIPTION ....................................................................................................... 16
6.1 SPI Mode ...................................................................................................................................... 16
6.2 I²C Mode ....................................................................................................................................... 17
7. CONTROL PORT REGISTER SUMMARY ......................................................................................... 18
8. CONTROL PORT REGISTER BIT DEFINITIONS .............................................................................. 19
8.1 Memory Address Pointer (MAP) ................................................................................................... 19
8.2 Default = ‘000000’Control 1 (01h) ................................................................................................. 19
8.3 Control 2 (02h) .............................................................................................................................. 19
8.4 Data Flow Control (03h) ............................................................................................................... 20
8.5 Clock Source Control (04h) .......................................................................................................... 20
8.6 Serial Audio Input Port Data Format (05h) ................................................................................... 21
8.7 Interrupt 1 Status (07h) (Read Only) ............................................................................................ 22
8.8 Interrupt 2 Status (08h) (Read Only) ............................................................................................ 22
8.9 Interrupt 1 Mask (09h) .................................................................................................................. 22
8.10 Interrupt 1 Mode MSB (0Ah) and Interrupt 1 Mode LSB (0Bh) ................................................... 23
8.11 Interrupt 2 Mask (0Ch) ................................................................................................................ 23
8.12 Interrupt 2 Mode MSB (0Dh) and Interrupt Mode 2 LSB (0Eh) .................................................. 23
8.13 Channel Status Data Buffer Control (12h) ..................................................................................23
8.14 User Data Buffer Control (13h) ................................................................................................... 24
8.15 Channel Status Bit or User Bit Data Buffer (20h - 37h) .............................................................. 24
8.16 CS8406 I.D. and Version Register (7Fh) (Read Only) ................................................................ 24
9. PIN DESCRIPTION - SOFTWARE MODE ....................................................................................... 25
10. HARDWARE MODE .......................................................................................................................... 27
10.1 Channel Status, User and Validity Data ..................................................................................... 27
10.2 Serial Audio Port ......................................................................................................................... 28
11. PIN DESCRIPTION - HARDWARE MODE ....................................................................................... 29
12. APPLICATIONS ................................................................................................................................ 31
12.1 Reset, Power Down and Start-Up .............................................................................................. 31
12.2 ID Code and Revision Code ....................................................................................................... 31
12.3 Power Supply, Grounding, and PCB layout ................................................................................ 31
12.4 Synchronization of Multiple CS8406s ......................................................................................... 31
13. PACKAGE DIMENSIONS ................................................................................................................ 32
14. ORDERING INFORMATION ............................................................................................................. 34
DS580F6 3
CS8406
15. APPENDIX A: EXTERNAL AES3/SPDIF/IEC60958 TRANSMITTER COMPONENTS ................... 35
15.1 AES3 Transmitter External Components .................................................................................... 35
15.2 Isolating Transformer Requirements .......................................................................................... 35
16. APPENDIX B: CHANNEL STATUS AND USER DATA BUFFER MANAGEMENT ........................ 36
16.1 AES3 Channel Status(C) Bit Management ................................................................................. 36
16.1.1 Accessing the E buffer ................................................................................................... 36
16.1.2 Serial Copy Management System (SCMS) .................................................................... 37
16.1.3 Channel Status Data E Buffer Access ........................................................................... 37
16.2 AES3 User (U) Bit Management ................................................................................................. 38
16.2.1 Mode 1: Transmit All Zeros ............................................................................................ 38
16.2.2 Mode 2: Block Mode ......................................................................................................38
17. REVISION HISTORY ......................................................................................................................... 39
LIST OF FIGURES
Figure 1. Audio Port Master Mode Timing ................................................................................................... 6
Figure 2. Audio Port Slave Mode and Data Input Timing............................................................................. 6
Figure 3. SPI Mode Timing .......................................................................................................................... 7
Figure 4. I²C Mode Timing ........................................................................................................................... 8
Figure 5. Recommended Connection Diagram for Software Mode ............................................................. 9
Figure 6. Recommended Connection Diagram for Hardware Mode .......................................................... 10
Figure 7. Serial Audio Input Example Formats .......................................................................................... 12
Figure 8. AES3 Transmitter Timing for C, U, and V Pin Input Data, Stereo Mode..................................... 14
Figure 9. AES3 Transmitter Timing for C, U, and V Pin Input Data, Mono Mode ...................................... 15
Figure 10. Control Port Timing in SPI Mode .............................................................................................. 16
Figure 11. Control Port Timing, I²C Slave Mode Write............................................................................... 17
Figure 12. Control Port Timing, I²C Slave Mode Read............................................................................... 17
Figure 13. Hardware Mode Data Flow ....................................................................................................... 27
Figure 14. Professional Output Circuit ....................................................................................................... 35
Figure 15. Consumer Output Circuit (VL = 5.0 V) ...................................................................................... 35
Figure 16. TTL/CMOS Output Circuit......................................................................................................... 35
Figure 17. Channel Status Data Buffer Structure....................................................................................... 36
Figure 18. Flowchart for Writing the E Buffer ............................................................................................. 37
LIST OF TABLES
Table 1. Control Register Map Summary................................................................................................... 18
Table 2. Hardware Mode COPY/C and ORIG Pin Functions..................................................................... 28
Table 3. Hardware Mode Serial Audio Port Format Selection ................................................................... 28
Table 4. Hardware Mode OMCK Clock Ratio Selection............................................................................. 28
Table 5. Equivalent Register Settings of Serial Audio Input Formats in Hardware Mode .......................... 28
4DS580F6
CS8406
1. CHARACTERISTICS AND SPECIFICATIONS
(All Min/Max characteristics and specifications are guaranteed over the Specified Operating Conditions. Typical
performance characteristics and specifications are derived from measurements taken at nominal supply voltages
and TA = 25°C.)
SPECIFIED OPERATING CONDITIONS
(GND = 0 V, all voltages with respect to 0 V)
ABSOLUTE MAXIMUM RATINGS
(GND = 0 V; all voltages with respect to 0 V. Operation beyond these limits may result in permanent damage to the
device. Normal operation is not guaranteed at these extremes.)
Notes:
1. Transient currents of up to 100 mA will not cause SCR latch-up.
DC ELECTRICAL CHARACTERISTICS
(GND = 0 V; all voltages with respect to 0 V.)
2. Power Down Mode is defined as RST = LO with all clocks and data lines held static.
3. Normal operation is defined as RST = HI.
4. Assumes that no inputs are left floating. It is recommended that all digital inputs be driven high or low
at all times.
Parameter Symbol Min Typ Max Units
Power Supply Voltage VD
VL
3.14
3.14
3.3 or 5.0
3.3 or 5.0
5.25
5.25
V
V
Ambient Operating Temperature: Commercial Grade
Automotive Grade
TA
TA
-10
-40
-
-
+70
+85
°C
°C
Parameter Symbol Min Max Units
Power Supply Voltage VD, VL - 6.0 V
Input Current, Any Pin Except Supplies (Note 1) Iin -±10mA
Input Voltage Vin -0.3 VL + 0.3 V
Ambient Operating Temperature (power applied) TA-55 125 °C
Storage Temperature Tstg -65 150 °C
Parameters Symbol Min Typ Max Units
Power-Down Mode (Note 2)
Supply Current in power down VD = 3.3 V
VD = 5.0 V
VL = 3.3 V
VL = 5.0 V
ID
ID
IL
IL
-
-
-
-
20
40
0
0
-
-
-
-
A
A
A
A
Normal Operation (Note 3)
Supply Current at 48 kHz frame rate (Note 4) VD = 3.3 V
VD = 5.0 V
VL = 3.3 V
VL = 5.0 V
ID
ID
IL
IL
-
-
-
-
1.9
3.5
6.5
10.6
-
-
-
-
mA
mA
mA
mA
Supply Current at 192 kHz frame rate (Note 4) VD = 3.3 V
VD = 5.0 V
VL = 3.3 V
VL = 5.0 V
ID
ID
IL
IL
-
-
-
-
7.6
12.7
7.2
12
-
-
-
-
mA
mA
mA
mA
DS580F6 5
CS8406
DIGITAL INPUT CHARACTERISTICS
DIGITAL INTERFACE SPECIFICATIONS
(GND = 0 V; all voltages with respect to 0 V.)
TRANSMITTER CHARACTERISTICS
SWITCHING CHARACTERISTICS
(Inputs: Logic 0 = 0 V, Logic 1 = VL; CL = 20 pF)
Parameters Symbol Min Typ Max Units
Input Leakage Current Iin --±0.5A
Input Hysteresis (all inputs except OMCK) - 0.25 - V
Parameters Symbol Min Max Units
High-Level Output Voltage (IOH = -3.2 mA), except TXP/TXN VOH VL - 1.0 - V
Low-Level Output Voltage (IOH = 3.2 mA), except TXP/TXN VOL -0.4V
High-Level Output Voltage, TXP, TXN (21 mA at VL = 5.0 V)
(15 mA at VL = 3.3 V)
VL - 0.7
VL - 0.7
VL
VL
V
V
Low-Level Output Voltage, TXP, TXN (21 mA at VL = 5.0 V)
(16 mA at VL = 3.3 V)
-
-
0.7
0.7
V
V
High-Level Input Voltage VD = 5.0 V
VD = 3.3 V
VIH 2.75
2.0
VL + 0.3
VL + 0.3
V
V
Low-Level Input Voltage VD = 5.0 V
VD = 3.3 V
VIL -0.3
-0.3
0.8
0.8
V
V
Parameters Symbol Typ Units
TXP Output Resistance VL = 5.0 V
VL = 3.3 V
RTXP 26.5
33.5
TXN Output Resistance VL = 5.0 V
VL = 3.3 V
RTXN 26.5
33.5
Parameter Symbol Min Typ Max Units
RST pin Low Pulse Width 200 - - s
OMCK Frequency for OMCK = 512*Fs 4.1 - 98.4 MHz
OMCK Low and High Width for OMCK = 512*Fs 4.1 - - ns
OMCK Frequency for OMCK = 384*Fs 3.1 - 73.8 MHz
OMCK Low and High Width for OMCK = 384*Fs 6.1 - - ns
OMCK Frequency for OMCK = 256*Fs 2.0 - 49.2 MHz
OMCK Low and High Width for OMCK = 256*Fs 8.1 - - ns
OMCK Frequency for OMCK = 128*Fs 1.0 - 24.6 MHz
OMCK Low and High Width for OMCK = 128*Fs 18.3 - - ns
Frame Rate 8-192kHz
AES3 Transmitter Output Jitter - 200 - ps RMS
6DS580F6
CS8406
SWITCHING CHARACTERISTICS - SERIAL AUDIO PORTS
(Inputs: Logic 0 = 0 V, Logic 1 = VL; CL = 20 pF)
Notes:
5. The active edge of ISCLK is programmable in Software Mode.
6. The polarity of ILRCK is programmable in Software Mode.
7. Prevents the previous ISCLK edge from being interpreted as the first one after ILRCK has changed.
8. This setup time ensures that this ISCLK edge is interpreted as the first one after ILRCK has changed.
Parameter Symbol Min Typ Max Units
SDIN Setup Time Before ISCLK Active Edge (Note 5) tds 10 - - ns
SDIN Hold Time After ISCLK Active Edge (Note 5) tdh 8--ns
Master Mode
OMCK to ISCLK active edge delay (Note 5) tsmd 0-17ns
OMCK to ILRCK delay (Note 6) tlmd 0-16ns
ISCLK and ILRCK Duty Cycle - 50 - %
Slave Mode
ISCLK Period tsckw 36 - - ns
ISCLK Input Low Width tsckl 14.4 - - ns
ISCLK Input High Width tsckh 14.4 - - ns
ISCLK Active Edge to ILRCK Edge (Note 7) tlrckd 10 - - ns
ILRCK Edge Setup Before ISCLK Active Edge (Note 8) tlrcks 10 - - ns
ISCLK
ILRCK
(output)
(output)
OMCK
(input)
tsmd
tlmd
sckh sckl
sckw
t
t
t
(input)
(input)
SDIN
dh
t
ds
t
lrcks
t
lrckd
t
ISCLK
ILRCK
Figure 1. Audio Port Master Mode Timing Figure 2. Audio Port Slave Mode and Data Input Timing
DS580F6 7
CS8406
SWITCHING CHARACTERISTICS - CONTROL PORT - SPI MODE
(Inputs: Logic 0 = 0 V, Logic 1 = VL; CL = 20 pF)
Notes:
9. If Fs is lower than 51.850 kHz, the maximum CCLK frequency should be less than 115 Fs. This is dic-
tated by the timing requirements necessary to access the Channel Status and User Bit buffer memory.
Access to the control register file can be carried out at the full 6 MHz rate.
10. Tsch must be greater than the larger of the two values, either 1/256FS + 8 ns, or 66 ns.
11. Data must be held for sufficient time to bridge the transition time of CCLK.
12. For fsck < 1 MHz.
Parameter Symbol Min Typ Max Units
CCLK Clock Frequency (Note 9) fsck 0-6.0MHz
CS High Time Between Transmissions tcsh 1.0 - - s
CS Falling to CCLK Edge tcss 20 - - ns
CCLK Low Time tscl 66 - - ns
CCLK High Time (Note 10) tsch MAX ((1/256 FS + 8), 66) ns
CDIN to CCLK Rising Setup Time tdsu 40 - - ns
CCLK Rising to DATA Hold Time (Note 11) tdh 15 - - ns
CCLK Falling to CDOUT Stable tpd --50ns
Rise Time of CDOUT tr1 --25ns
Fall Time of CDOUT tf1 --25ns
Rise Time of CCLK and CDIN (Note 12) tr2 --100ns
Fall Time of CCLK and CDIN (Note 12) tf2 --100ns
tr2 tf2
tdsu tdh
tsch
tscl
CS
CCLK
CDIN
tcss
tpd
CDOUT
tcsh
Figure 3. SPI Mode Timing
8DS580F6
CS8406
SWITCHING CHARACTERISTICS - CONTROL PORT - I²C MODE
(Inputs: Logic 0 = 0 V, Logic 1 = VL; CL = 20 pF)
13. Data must be held for sufficient time to bridge the 300 ns transition time of SCL.
Parameter Symbol Min Typ Max Units
SCL Clock Frequency fscl - - 100 kHz
Bus Free Time Between Transmissions tbuf 4.7 - - s
Start Condition Hold Time (prior to first clock pulse) thdst 4.0 - - s
Clock Low Time tlow 4.7 - - s
Clock High Time thigh 4.0 - - s
Setup Time for Repeated Start Condition tsust 4.7 - - s
SDA Hold Time from SCL Falling (Note 13) thdd 0- -s
SDA Setup Time to SCL Rising tsud 250 - - ns
Rise Time of Both SDA and SCL Lines tr- - 1000 ns
Fall Time of Both SDA and SCL Lines tf- - 300 ns
Setup Time for Stop Condition tsusp 4.7 - - s
tbuf thdst thdst
tlow tr
tf
thdd
thigh
tsud tsust
tsusp
Stop Start Start Stop
Repeated
SDA
SCL
Figure 4. I²C Mode Timing
DS580F6 9
CS8406
2. TYPICAL CONNECTION DIAGRAMS
CS8406
+3.3 V or +5.0 V
GND
RXP
ILRCK
ISCLK
SDIN
AES3 /
S/PDIF
Source
Microcontroller SCL / CCLK
SDA / CDOUT
RST
AD1 / CDIN
VD VL
TXP
0.1 F
AD0 / CS
Serial
Audio
Source
Clock Source
and Control OMCK
AD2
TXN
H/S
TCBL
To/from other
CS8406's
INT
47k
U
Transmission
Interface
User Data
Source
+3.3 V or +5.0 V
0.1 F
Figure 5. Recommended Connection Diagram for Software Mode
10 DS580F6
CS8406
CS8406
+3.3 V or +5.0 V
GND
ILRCK
ISCLK
SDIN
Hardware
Control
APMS
TCBLD
RST
SFMT0
VD VL
TXP
0.1 F
Serial
Audio
Source
Clock Source
and Control OMCK
SFMT1
TXN
H/S
TCBL
To/from other
CS8406's
CEN
47k
U
Transmission
Interface
User Data
Source
EMPH
AUDIO
ORIG
VValidity
Source
+3.3 V or +5.0 V
0.1 F
47k
C Data
Source
COPY/C
HWCK1
HWCK0
Figure 6. Recommended Connection Diagram for Hardware Mode
DS580F6 11
CS8406
3. GENERAL DESCRIPTION
The CS8406 is a monolithic CMOS device which encodes a nd transmits audio data according to the AES3,
IEC60958, S/PDIF, and EIAJ CP1201 interface standards. The CS8406 accepts audio, channel status and user da-
ta, which is then multiplexed, encoded, and driven onto a cable.
The audio data is input through a configurable, 3-wire input port. The channel status bits and user bit data are input
through an SPI or I²C Mode microcontroller port and may be assembled in separate block sized buffers.
For systems with no microcontroller, a Stand-Alone Mode allows direct access to channel status and user data input
pins.
Target applications include CD-R, DAT, DVD, MD and VTR equipment, mixing consoles, digital audio transmission
equipment, high quality A/D converters, effects processors, set-top TV boxes, and computer audio systems.
Figure 5 shows the supply and external connections to the CS8406 when configured for operation with a microcon-
troller. Figure 6 shows the supply and external connections to the CS8406 when configured for operation without a
microcontroller.
3.1 AES3 and S/PDIF Standards Documents
This data sheet assumes that the user is familiar with the AES3 and S/PDIF data formats. It is advisable to
have current copies of the AES3 and IEC60958 specifications on hand for easy reference.
The latest AES3 standard is available from the Audio Engi neering Society or ANSI at www.aes.org or
www.ansi.org. Obtain the latest IEC60958 standard from ANSI or from the International Electrotechnical
Commission at www.iec.ch. The latest EIAJ CP-1201 standard is available from the Japanese Electronics
Bureau.
Application Note 22: Overview of Digital Audio Interf ace Data Structures contains a useful tutorial on digital
audio specifications, but it should not be considered a substitute for the standards.
The paper An Understanding and Im plementation of the SCMS Serial Copy M anagement System for Digi tal
Audio Transmission, by Clifton Sanchez, is an excellent tutorial on SCMS. It is available from the AES as
reprint 3518.
12 DS580F6
CS8406
4. THREE-WIRE SERIAL INPUT AUDIO PORT
A 3-wire serial audio input port is provided. The interface format can be adjusted to suit the attached device through
the control registers. The following parameters are adjustable:
• Master or slave
• Serial clock frequency
• Audio data resolution
• Left or right justification of the data relative to left/right clock
• Optional one-bit cell delay of the first data bit
• Polarity of the bit clock
• Polarity of the left/right clock (by setting the appropriate control bits, many formats are possible.)
Figure 7 shows a selection of common input formats with the corresponding control bit settings.
In Master Mode, the left/right clock and the serial bit clock are outputs, derived from the OMCK input pin master
clock.
In Slave Mode, the left/right clock and the serial bit clock are inputs. The left/right clock must be synchronous to the
OMCK master clock, but the serial bit clock can be asynchronous and discontinuous if required. The left/right clock
should be continuous, but the duty cycle can be less than the specified typical value of 50% if enough serial clocks
are present in each phase to clock all the data bits.
Figure 7. Serial Audio Input Example Formats
X = don’t care to match format, but does need to be set to the desired setting
+ I²S can accept an arbitrary number of bits, determined by the number of ISCLK cycles
* See Serial Input Port Data Format Register Bit Descriptions for an explanation of the meaning of each bit
SIMS* SISF* SIRES[1:0]* SIJUST* SIDEL* SISPOL* SILRPOL*
Left Justified X X 00+ 0 0 0 0
I²S XX00+0101
Right Justified X X XX 1 0 0 0
DS580F6 13
CS8406
5. AES3 TRANSMITTER
The CS8406 includes an AES3 digital audio transmitter. A comprehensive buffering scheme provides write access
to the channel status and user data. This buffering scheme is described in “Appendix B: Channel Status and User
Data Buffer Management” on page 36.
The AES3 transmitter encodes and transmits audio and digital data according to the AES3, IEC60958 (S/PDIF), and
EIAJ CP-1201 interface standards. Audio and control data are multiplexed together and bi-phase mark encoded.
The resulting bit stream is driven to an output connector either directly or through a transformer. The transmitter is
clocked from the clock input pin, OMCK. If OMCK is asynchronous to the data source, an interrupt bit (TSLIP) is
provided that will go high every time a data sample is dropped or repeated.
The channel status (C) and user (U) bits in the transmitted data stream are taken from storage areas within the
CS8406. The user can access the internal storage or configure the CS8406 to run in one of several automatic
modes. “Appendix B: Channel Status and User Data Buffer Management” on page 36 provides detailed descriptions
of each automatic mode and describes methods of accessing the storage areas. The transmitted user bit data can
optionally be input through the U pin, under the control of a control port register bit.
Figures 8 and 9 show the C/U/V timing requirements.
5.1 TXN and TXP Drivers
The AES3 transmitter line drivers are low skew, low impedance, differential outputs capable of driving ca-
bles directly. Both drivers are set to ground during reset (RST = LOW), when no AES3 transmit clock is pro-
vided, and optionally under the control of a register bit. The CS8406 also allows immediate muting of the
AES3 transmitter audio data through a control register bit.
External components are used to terminate and isolate the external cable from the CS8406. These compo-
nents are detailed in “Appendix A: External AES3/SPDIF/IEC60958 Transmitter Components” on page 35.
5.2 Mono Mode Operation
An alternate method for tr ansmitting an AES3 192 kHz sample rate stream is Mono M ode. Mono Mode is
implemented by using the two sub-frames in a 96 kHz biphase encoded stream to carry consecutive sam-
ples of a single channel of a 192 kHz PCM stream (i.e. a mono signal). This allows older equipment, whose
AES3 transmitters and receivers are not rated for 192 kHz frame rate operation, to handle 192 kHz sample
rate information. In this Mono Mode, two AES3 cables and two CS8406's are needed for stereo data trans-
fer. The CS8406 is set to Mono Mode by the MMT control bit.
In Mono Mode, the input port will run at the audio sample rate (Fs), while the AES3 transmitter frame rate
will be at Fs/2. Consecutive left or right channel serial audio data samples may be selected for transmission
on the A and B sub-frames, and the channel status block transmitted is also selectable.
Using Mono Mode is only necessary if the incoming audio sample rate is already at 192 kHz and contains
both left and right audio data words. The “Mono Mode” AES3 output stream may also be achieved by keep-
ing the CS8406 in normal stereo mode, and placing consecutive audio samples in the left and right positions
in an incoming 96 kHz word rate data stream. Figure 9 shows the C/U/V timing requirements.
5.3 Transmitted Frame and Channel Status Boundary Timing
The TCBL pin is used to indicate the start of transmitted channel status block boundaries and may be an
input or an output.
In some applications, it may be necessary to contro l the precise timing of the transmitted AES3 frame
boundaries. This may be achieved in two ways:
14 DS580F6
CS8406
a) With TCBL set to input, driving TCBL high for >3 OMCK clocks will cause a frame start, as well as a new
channel status block start.
b) If the serial audio input port is in Slave Mode and TCBL is set to output, the start of the A channel sub-
frame will be aligned with the leading edge of ILRCK.
The timing of TCBL, VLRCK, C, U, and V are illustrated in Figure 8 and Figure 9. VLRCK is the internal vir-
tual word clock signal, and is used here only to illustrate the timing of the C, U, and V bits. In Stereo Mode
VLRCK = AES3 frame rate and in Mono Mode VLRCK = 2 x AES3 frame rate. If the serial audio input port
is set to Slave Mode and TCBL is an output, VLRCK = ILRCK when SILRPOL = 0 and VLRCK = ILRCK
when SILRPOL = 1. If the serial audio input port is set to master mode and TCBL is a n input,
VLRCK = ILRCK when SILRPOL = 0 and VLRCK = ILRCK when SILRPOL = 1.
VCU[0] VCU[1] VCU[2] VCU[3] VCU[4]
VLRCK
V/C/U
Data [4] Data [5] Data [6] Data [7] Data [8]
SDIN
Data [0] Data [1] Data [2] Data [3] Data [4]
TXP(N) ZYXYX
Tsetup Thold
Tth
TCBL
Figure 8. AES3 Transmitter Timing for C, U, and V Pin Input Data, Stereo Mode
Note:
1. Tsetup 15% AES3 frame rate
2. Thold =0
3. Tth > 3 OMCKS if TCBL is an input
DS580F6 15
CS8406
U[0] U[2]
Data [4] Data [5] Data [6] Data [7] Data [8]
Data [0]* Data [2]* Data [4]*Z Y X
* Assume MMTLR = 0
Data [1]* Data [3]* Data [5]*ZYX
* Assume MMTLR = 1
Tth
VLRCK
U
SDIN
TXP(N)
TCBL
TXP(N)
Figure 9. AES3 Transmitter Timing for C, U, and V Pin Input Data, Mono Mode
Note:
1. Tsetup 15% AES3 frame rate
2. Thold =0
3. Tth > 3 OMCKS if TCBL is an input
16 DS580F6
CS8406
6. CONTROL PORT DESCRIPTION
The control port is used to access the registers, allowing the CS8406 to be configured for the desired operational
modes and formats. The operation of the control port may be completely asynchronous with respect to the audio
sample rates. However, to avoid potential interference problems, the control port pins should remain static if no op-
eration is required.
The control port has two modes: SPI and I²C, with the CS8406 acting as a slave device. SPI Mode is selected if
there is a high to low transition on the AD0/CS pin, after the RST pin has been brought high. I²C Mode is selected
by connecting the AD0/CS pin through a resistor to VL or GND, thereby permanently selecting the desired AD0 bit
address state.
6.1 SPI Mode
In SPI Mode, CS is the CS8406 chip select signal, CCLK is the control port bit clock (input into the CS8406
from the microcontroller), CDIN is the input data line from the microcontroller, and CDOUT is the output data
line to the microcontroller. Data is clocked in on the rising edge of CCLK and out on the falling edge.
Figure 10 shows the operation of the control port in SPI Mode. To write to a register, bring CS low. The first
seven bits on CDIN form the chip address and must be 0010000. The eighth bit is a read/write indicator
(R/W), which should be low to write. The next eight bits form the Memory Address Pointer (MAP), which is
set to the address of the register that is to be updated. The next eight bits are the data which will be placed
into the register designated by the MAP. During writes, the CDOUT output stays in the Hi-Z state. It may be
externally pulled high or low with a 47 k resistor, if desired.
To read a register, the MAP has to be set to the correct address by executing a partial write cycle which
finishes (CS high) immediately after the MAP byte. To begin a read, bring CS low, send out the chip address
and set the read/write bit (R/W) high. The next falling edge of CCLK will clock out the MSB of the addressed
register (CDOUT will leave the high impedance state). The MAP automatically increments so data for suc-
cessive registers will appear consecutively.
MAP
MSB LSB
DATA
byte 1 byte n
R/W R/W
ADDRESS
CHIP
ADDRESS
CHIP
CDIN
CCLK
CS
CDOUT MSB LSB MSB LSB
0010000
0010000
MAP = Memory Address Pointer, 7 bits, MSB first
High Impedance
Figure 10. Control Port Timing in SPI Mode
DS580F6 17
CS8406
6.2 I²C Mode
In I²C Mode, SDA is a bidirectional data line. Data is clocked into and out of the part by the clock, SCL. There
is no CS pin. Pins AD0, AD1, and AD2 form the three least significant bits of the chip address and should
be connected to VL or GND as desired.
The signal timing for both a read and write cycle are shown in Figure 11 and Figure 12. A Start condition is
defined as a falling transition of SDA while the clock is high. A Stop condition is a rising transition while the
clock is high. All other transitions of SDA occur while the clock is low. The first byte sent to the CS8406 after
a Start condition consists of a 7 bit chip address field and a R/W bit (high for a read, low for a write). The
upper 4 bits of the 7-bit address field are fixed at 0010. To communicate with a CS8406, the chip address
field, which is the first byte sent to the CS8406, should match 0010 followed by the settings of the AD2, AD1,
and AD0 pins. The eighth bit of the address is the R/W bit. If the operation is a write, the next byte is the
Memory Address Pointer (MAP) which selects the register to be read or written. If the operation is a read,
the contents of the register pointed to by the MAP will be output. Th e MAP automatically increments, so
consecutive registers can read from or written to e asily. Each byte is se parated by an acknowled ge bit
(ACK). The ACK bit is output from the CS8406 after each input byte is read, and is input to the CS8406 from
the microcontroller after each transmitted byte.
Since the read operation cannot set the MAP, an aborted write operation is used as a preamble. As shown
in Figure 12, the write operation is aborted after the acknowledge for the MAP by sending a stop condition.
4 5 6 7 24 25
SCL
0 0 1 0 AD2 AD1 AD0 0
CHIP ADDRESS (WRITE) MAP DATA DATA +1
START
ACK
STOP
ACKACKACK
SDA 6 5 4 3 2 1 7 6 1 0 7 6 1 0 7 6 1 0
0 1 2 3 8 9 12 16 17 18 19 10 11 13 14 15 27 28
26
DATA +n
Figure 11. Control Port Timing, I²C Slave Mode Write
SCL
CHIP ADDRESS (WRITE) MAP DATA DATA +1
START
ACK
STOP
ACK
ACK
ACK
SDA 6 5 4 3 2 1 0
CHIP ADDRESS (READ)
START
7 0 7 0 7 0
NO
16 8 9 12 13 14 15 4 5 6 7 0 1 20 21 22 23 24 26 27 28
2 3 10 11 17 18 19 25
ACK
DATA + n
STOP
0 0 1 0 AD2 AD1 AD0 0 0 0 1 0 AD2 AD1 AD0 1
Figure 12. Control Port Timing, I²C Slave Mode Read
18 DS580F6
CS8406
7. CONTROL PORT REGISTER SUMMARY
Note: Reserved registers must not be written to during normal operation. Some reserved registers are used for
test modes, which can completely alter the normal operation of the CS8406.
Addr
(HEX)
Function 7 6 5 4 3 2 1 0
00 Reserved 0 0 0 0 0 0 0 0
01 Control 1 0 VSET 0 MUTEAES 0 INT1 INT0 TCBLD
02 Control 2 0 0 0 0 0 MMT MMCST MMTLR
03 Data Flow Control 0 TXOFF AESBP 0 0 0 0 0
04 Clock Source Control 0 RUN CLK1 CLK0 0 0 0 0
05 Serial Input Format SIMS SISF SIRES1 SIRES0 SIJUST SIDEL SISPOL SILRPOL
06 Reserved 0 0 0 0 0 0 0 0
07 Interrupt 1 Status TSLIP 0 0 0 0 0 EFTC 0
08 Interrupt 2 Status 0 0 0 0 0 EFTU 0 0
09 Interrupt 1 Mask TSLIPM 0 0 0 0 0 EFTCM 0
0A Interrupt 1 Mode (MSB) TSLIP1 0 0 0 0 0 EFTC1 0
0B Interrupt 1 Mode (LSB) TSLIP0 0 0 0 0 0 EFTC0 0
0C Interrupt 2 Mask 0 0 0 0 0 EFTUM 0 0
0D Interrupt 2 Mode (MSB) 0 0 0 0 0 EFTU1 0 0
0E Interrupt 2 Mode (LSB) 0 0 0 0 0 EFTU0 0 0
0F-11 Reserved 0 0 0 0 0 0 0 0
12 CS Data Buffer Control 0 0 BSEL 0 0 EFTCI CAM 0
13 U Data Buffer Control 0 0 0 UD UBM1 UBM0 0 EFTUI
1D-1F Reserved 0 0 0 0 0 0 0 0
20-37 C or U Data Buffer
7F ID and Version ID3 ID2 ID1 ID0 VER3 VER2 VER1 VER0
Table 1. Control Register Map Summary
DS580F6 19
CS8406
8. CONTROL PORT REGISTER BIT DEFINITIONS
8.1 Memory Address Pointer (MAP)
Not a register
MAP[6:0] - Memory Address Pointer. Will automatically increment after each read or write.
8.2 Default = ‘000000’Control 1 (01h)
VSET - Transmitted Validity bit level
Default = ‘0’
0 - Indicates data is valid, linear PCM audio data
1 - Indicates data is invalid or not linear PCM audio data
MUTEAES - Mute control for the AES transmitter output
Default = ‘0’
0 - Not Muted
1 - Muted
INT1:0 - Interrupt output pin (INT) control
Default = ‘00’
00 - Active high; high output indicates interrupt condition has occurred
01 - Active low, low output indicates an interrupt condition has occurred
10 - Open drain, active low. Requires an external pull-up resistor on the INT pin.
11 - Reserved
TCBLD - Transmit Channel Status Block pin (TCBL) direction specifier
Default = ‘0’
0 - TCBL is an input
1 - TCBL is an output
8.3 Control 2 (02h)
MMT - Select AES3 transmitter mono or stereo operation
Default = ‘0’
0 - Normal stereo operation
1 - Output either left or right channel inputs into consecutive subframe outputs (Mono Mode, left or right is
determined by MMTLR bit)
76543210
0 MAP6 MAP5 MAP4 MAP3 MAP2 MAP1 MAP0
76543210
0 VSET 0 MUTEAES 0 INT1 INT0 TCBLD
76543210
0 0 0 0 0 MMT MMTCS MMTLR
20 DS580F6
CS8406
MMTCS - Select A or B channel status data to transmit in Mono Mode
Default = ‘0’
0 - Use channel A CS data for the A subframe and use channel B CS data for the B subframe
1 - Use the same CS data for both the A and B subframe outputs. If MMTLR = 0, use the left channel CS
data. If MMTLR = 1, use the right channel CS data.
MMTLR - Channel Selection for AES Transmitter Mono Mode
Default = ‘0’
0 - Use left channel input data for consecutive subframe outputs
1- Use right channel input data for consecutive subframe outputs
8.4 Data Flow Control (03h)
The Data Flow Control register configures the flow of audio data. The output data should be muted prior to
changing bits in this register to avoid transients.
TXOFF - AES3 Transmitter Output Driver Control
Default = ‘0
0 - AES3 transmitter output pin drivers normal operation
1 - AES3 transmitter output pin drivers drive to 0 V.
AESBP - AES3 bypass mode selection
Default = ‘0’
0 - Normal operation
1 - Connect the AES3 transmitter driver input di rectly to the RXP pin, which becomes a normal TTL
threshold digital input.
8.5 Clock Source Control (04h)
This register configures the clock sources of various blocks. In conjunction with the Data Flow Control reg-
ister, various Receiver/Transmitter/Transceiver modes may be selected.
RUN - Controls the internal clocks, allowing the CS8406 to be placed in a “powered down” low current con-
sumption, state.
Default = ‘0’
0 - Internal clocks are stopped. Internal state machines are reset. The fully static
control port registers are operational, allowing registers to be read or changed. Reading and
writing the U and C data buffers is not possible. Power consumption is low.
1 - Normal part operation. This bit must be set to 1 to allow the CS8406 to begin operation.
All input clocks should be stable in frequency and phase when RUN is set to 1.
CLK1:0 - Output master clock (OMCK) input frequency to output sample rate (Fs) ratio selector. If these bits
are changed during normal operation, always stop the CS8406 first (RUN = 0), write the new value, then
start the CS8406 (RUN = 1).
7 6 543210
0 TXOFF AESBP 0 0 0 0 0
7 6 543210
0 RUN CLK1 CLK0 0 0 0 0
DS580F6 21
CS8406
Default = ‘00’
00 - OMCK frequency is 256*Fs
01 - OMCK frequency is 384*Fs
10 - OMCK frequency is 512*Fs
11 - OMCK frequency is 128*Fs
8.6 Serial Audio Input Port Data Format (05h)
SIMS - Master/Slave Mode Selector
Default = ‘0’
0 - Serial audio input port is in Slave Mode
1 - Serial audio input port is in Master Mode
SISF - ISCLK frequency (for Master Mode)
Default = ‘0’
0 - 64*Fs
1 - 128*Fs
SIRES1:0 - Resolution of the input data, for right-justified formats
Default = ‘00’
00 - 24-bit resolution
01 - 20-bit resolution
10 - 16-bit resolution
11 - Reserved
SIJUST - Justification of SDIN data relative to ILRCK
Default = ‘0’
0 - Left-justified
1 - Right-justified
SIDEL - Delay of SDIN data relative to ILRCK, for left-justified data formats
Default = ‘0’
0 - MSB of SDIN data occurs in the first ISCLK period after the ILRCK edge (Left-Justified Mode)
1 - MSB of SDIN data occurs in the second ISCLK period after the ILRCK edge (I²S Mode)
SISPOL - ISCLK clock polarity
Default = ‘0’
0 - SDIN sampled on rising edges of ISCLK
1 - SDIN sampled on falling edges of ISCLK
SILRPOL - ILRCK clock polarity
Default = ‘0’
0 - SDIN data is for the left channel when ILRCK is high
1 - SDIN data is for the right channel when ILRCK is high
76543210
SIMS SISF SIRES1 SIRES0 SIJUST SIDEL SISPOL SILRPOL
22 DS580F6
CS8406
8.7 Interrupt 1 Status (07h) (Read Only)
For all bits in this register, a ‘1’ means the associated interrupt condition has occurred at least once since
the register was last read. A ‘0’ me ans the associated interrupt condition has NOT occurred since the last
reading of the register. Reading the register resets all bits to ‘0’, unless the Interrupt Mode is set to level and
the interrupt source is still true. Status bits that are masked off in the associated mask register will always
be ‘0’ in this register. This register defaults to 00h.
TSLIP - AES3 transmitter source data slip interrupt
In data flows where OMCK, which clocks the AES3 transmitter, is asynchronous to the data source, this bit
will go high every time a data sample is dropped or repeated. When TCBL is an input, this bit will go high
on receipt of a new TCBL signal.
EFTC - E to F C-buffer transfer interrupt. The source for this bit is true during the E to F buffer transfer in
the C bit buffer management process.
8.8 Interrupt 2 Status (08h) (Read Only)
For all bits in this register, a ‘1’ means the associated interrupt condition has occurred at least once since
the register was last read. A ‘0’ me ans the associated interrupt condition has NOT occurred since the last
reading of the register. Reading the register resets all bits to ‘0’, unless the Interrupt Mode is set to level and
the interrupt source is still true. Status bits that are masked off in the associated mask register will always
be ‘0’ in this register. This register defaults to 00h.
EFTU - E to F U-buffer transfer interrupt. (Block Mode only) The source of this bit is true during the E to F
buffer transfer in the U bit buffer management process.
8.9 Interrupt 1 Mask (09h)
The bits of this register serve as a mask for the Interrupt 1 register. If a mask bit is set to 1, the error is un-
masked, meaning that its occurrence will affect the INT pin and the status register. If a mask bit is set to 0,
the error is mas ked, meaning that its occurrence will not affect the INT pin or the status register. The bit
positions align with the corresponding bits in Interrupt 1 register. This register defaults to 00h.
7 6 543210
TSLIP 0 0 0 0 0 EFTC 0
7 6 543210
00000EFTU00
7 6 543210
TSLIPM 0 0 0 0 0 EFTCM 0
DS580F6 23
CS8406
8.10 Interrupt 1 Mode MSB (0Ah) and Interrupt 1 Mode LSB (0Bh)
The two Interrupt Mode registers form a 2-bit code for each Interrupt Register 1 function. There are three
ways to set the INT pin active in accordance with the interrupt condition. In the Rising edge active mode,
the INT pin becomes active on the arrival of the interrupt condition. In the Falling edge active mode, the INT
pin becomes active on the removal of the interrupt condition. In Level active mode, the INT interrupt pin be-
comes active during the interrupt condition. Be aware that the active level (Active High or Low) only depends
on the INT[1:0] bits. These registers default to 00.
00 - Rising edge active
01 - Falling edge active
10 - Level active
11 - Reserved
8.11 Interrupt 2 Mask (0Ch)
The bits of this register serve as a mask for the Interrupt 2 register. If a mask bit is set to 1, the error is un-
masked, meaning that its occurrence will affect the INT pin and the status register. If a mask bit is set to 0,
the error is masked, meaning that its occurrence will not affect the INT pin or the status register. The bit
positions align with the corresponding bits in Interrupt 2 register. This register defaults to 00h.
8.12 Interrupt 2 Mode MSB (0Dh) and Interrupt Mode 2 LSB (0Eh)
The two Interrupt Mode registers form a 2-bit code for each Interrupt Register 1 function. There are three
ways to set the INT pin active in accordance with the interrupt condition. In the Rising edge active mode,
the INT pin becomes active on the arrival of the interrupt condition. In the Falling edge active mode, the INT
pin becomes active on the removal of the interrupt condition. In Level active mode, the INT interrupt pin be-
comes active during the interrupt condition. Be aware that the active level (Active High or Low) only depends
on the INT[1:0] bits. These registers default to 00.
00 - Rising edge active
01 - Falling edge active
10 - Level active
11 - Reserved
8.13 Channel Status Data Buffer Control (12h)
BSEL - Selects the data buffer register addresses to contain User data or Channel Status data
Default = ‘0’
0 - Data buffer address space contains Channel Status data
1 - Data buffer address space contains User data
76543210
TSLIP1 0 0 0 0 0 EFTC1 0
TSLIP0 0 0 0 0 0 EFTC0 0
76543210
00000EFTUM00
76543210
00000EFTU100
00000EFTU000
76543210
0 0 BSEL 0 0 EFTCI CAM 0
24 DS580F6
CS8406
Note: There are separate complete buffers for the Channel Status and User bits. This control bit deter-
mines which buffer appears in the address space.
EFTCI - E to F C-data buffer transfer inhibit bit.
Default = ‘0’
0 - Allow C-data E to F buffer transfers
1 - Inhibit C-data E to F buffer transfers
CAM - C-data buffer control port access mode bit
Default = ‘0’
0 - One-Byte Mode
1 - Two-Byte Mode
8.14 User Data Buffer Control (13h)
UD - User bit data source specifier
Default = ‘0’
0 - U Pin is the source of transmitted U data
1 - U data buffer is the source of transmitted U data
UBM1:0 - Sets the operating mode of the AES3 User bit manager
Default = ‘00’
00 - Transmit all zeros mode
01 - Block Mode
10 - Reserved
11 - Reserved
EFTUI - E to F U-data buffer transfer inhibit bit (valid in Block Mode only).
Default = ‘0’
0 - Allow U-data E to F buffer transfers
1 - Inhibit U-data E to F buffer transfers
8.15 Channel Status Bit or User Bit Data Buffer (20h - 37h)
Either the channel status data buffer E or the separate user bit data buffer E (provided UBM bits are set to
Block Mode) is accessible through these register addresses.
8.16 CS8406 I.D. and Version Register (7Fh) (Read Only)
ID[3:0] - ID code for the CS8406. Permanently set to 1110
VER[3:0] = 0001 (revision A)
VER[3:0] = 0010 (revision B)
7 6 543210
0 0 0 UD UBM1 UBM0 0 EFTUI
7 6 543210
ID3 ID2 ID1 ID0 VER3 VER2 VER1 VER0
DS580F6 25
CS8406
9. PIN DESCRIPTION - SOFTWARE MODE
VD 6Digital Power (Input) - Digital core power supply. Typically +3.3 V or +5.0 V.
VL 23 Logic Power (Input) - Input/Output power supply. Typically +3.3 V or +5.0 V.
GND 22 Ground (Input) - Ground for I/O and core logic.
RST 9
Reset (Input) - When RST is low, the CS8406 enters a low power mode and all internal states are reset.
On initial power up, RST must be held low until the power supply is stable, and all input clocks are stable
in frequency and phase. This is particularly true in Hardware Mode with multiple CS8406 devices, where
synchronization between devices is important.
H/S 24
Hardware/Software Control Mode Select (Input) -Determines the method of controlling the operation
of the CS8406, and the method of accessing CS and U data. In Software Mode, device control and CS
and U data access is primarily through the control port, using a microcontroller. To select Software
Mode, this pin should be permanently tied to GND.
TXN
TXP
25
26
Differential Line Drivers (Output) - These pins transmit biphase encoded data. The drivers are pulled
low while the CS8406 is in the reset state.
OMCK 21 Master Clock (Input) - The frequency can be set through the control port registers.
ISCLK 13 Serial Audio Bit Clock (Input/Output) - Serial bit clock for audio data on the SDIN pin.
ILRCK 12 Serial Audio Input Left/Right Clock (Input/Output) - Word rate clock for the audio data on the SDIN
pin.
SDIN 14 Serial Audio Data Port (Input) - Audio data serial input pin.
SDA / CDOUT SCL / CCLK
AD0 / CS AD1 / CDIN
AD2 TXP
RXP TXN
TSTN H/S
VD VL
TEST GND
TEST OMCK
RST U
TEST INT
TEST TEST
ILRCK TEST
ISCLK TEST
SDIN TCBL
1
2
3
4
5
6
7
821
22
23
24
25
26
27
28
9
10
11
12 17
18
19
20
13
14 15
16
26 DS580F6
CS8406
SDA/CDOUT 1
Serial Control Data I/O (I²C Mode) / Data Out (SPI) (Input/Output) - In I²C Mode, SDA is the control I/O
data line. SDA is open drain and requires an external pull-up resistor to VL. In SPI Mode, CDOUT is the
output data from the control port interface on the CS8406
SCL/CCLK 28 Control Port Clock (Input) - Serial control interface clock and is used to clock control data bits into and
out of the CS8406. In I²C Mode, SCL requires an external pull-up resistor to VL.
AD0/CS 2
Address Bit 0 (I²C Mode) / Control Port Chip Select (SPI) (Input) - A falling edge on this pin puts the
CS8406 into SPI Control Port Mode. With no falling edge, the CS8406 defaults to I²C Mode. In I²C
Mode, AD0 is a chip address pin. In SPI Mode, CS is used to enable the control port interface on the
CS8406
AD1/CDIN 27 Address Bit 1 (I²C Mode) / Serial Control Data in (SPI) (Input) - In I²C Mode, AD1 is a chip address
pin. In SPI Mode, CDIN is the input data line for the control port interface.
AD2 3
Address Bit 2 (I²C Mode) (Input) - Determines the AD2 address bit for the control port in I²C Mode, and
should be connected to GND or VL. If SPI Mode is used, the AD2 pin should be connected to either
GND or VL.
RXP 4Auxiliary AES3 Receiver Port (Input) - Input for an alternate, already AES3 coded, audio data source.
INT 19
Interrupt (Output) - Indicates key events during the operation of the CS8406. All bits affecting INT may
be unmasked through bits in the control registers. Indication of the condition(s) that initiated an interrupt
are readable in the control registers. The polarity of the INT output, as well as selection of a standard or
open drain output, is set through a control register. Once set true, the INT pin goes false only after the
interrupt status registers have been read and the interrupt status bits have returned to zero.
TCBL 15
Transmit Channel Status Block Start (Input/Output) - When operated as output, TCBL is high during
the first sub-frame of a transmitted channel status block, and low at all other times. When operated as
input, driving TCBL high for at least three OMCK clocks will cause the next transmitted sub-frame to be
the start of a channel status block.
U20
User Data (Input) - May optionally be used to input User data for transmission by the AES3 transmitter,
see Figure 4 for timing information. If not driven, a 47 k pull-down resistor is recommended for the U
pin. If the U pin is driven by a logic level output, a 100 series resistor is recommended.
TSTN 5Test In (Input) - This pin is an input used for test purposes. It must be tied to ground for normal operation.
TEST
7
8
10
11
16
17
18
Test Pins - These pins are unused inputs. It is recommended that these pins be tied to a supply (VL or
GND) to minimize leakage current. The CS8406 will operate correctly if these pins are left floating, how-
ever current consumption from VL will increase by 25 A per TEST pin that is left floating.
DS580F6 27
CS8406
10.HARDWARE MODE
The CS8406 has a Hardware Mode that allows the use of the device without a microcontroller. Hardware Mode is
selected by connecting the H/S pin to VL. The flexibility of the CS8406 is necessarily limited in Hardware Mode.
Various pins change function as described in the Hardware Mode pin description section.
The Hardware Mode data flow is shown in Figure 13. Audio data is input through the serial audio input port and rout-
ed to the AES3 transmitter.
10.1 Channel Status, User and Validity Data
The transmitted channel status, user and validity data can be input in two methods, determined by the state
of the CEN pin. Mode A is selected when the CEN pin is low. In Mode A, the user bit data and the validity
bit are input through the U and V pins, clocked by both edges of ILRCK. The channel status data is derived
from the state of the COPY/C, ORIG, EMPH, and AUDIO pins. Table 2 shows how the COPY/C and ORIG
pins map to channel status bits. In Consumer Mode, the transmitted category code is set to General (00h).
Mode B is selected when the CEN pin is high. In Mode B, the channel status, user data bits and the validity
bit are input serially through the COPY/C, U and V pins. Data is clocked into these pins at both edges of
ILRCK. Figure 9 shows the timing requirements.
AES3
Encoder
&Tx
Serial
Audio
Input
C, U, V Data Buffer
ILRCK
ISCLK
TXP
COPY/C ORIG EMPH AUDIO
VL
H/S
Output
Clock
Source
OMCK
Power supply pins are omitted from this diagram.
Please refer to the Typical Connection Diagram for hook-up details.
SDIN
SFMT1 SFMT0
TXN
CEN
U
V
APMS
TCBL
TCBLD
RST
Figure 13. Hardware Mode Data Flow
28 DS580F6
CS8406
The channel status block pin (TCBL) may be an input or an output, determined by the state of the TCBLD
pin.
10.2 Serial Audio Port
The serial audio input port data format is selected as shown in Table 3, and may be set to master or slave
by the state of the APMS input pin. The OMCK clock ratio is selected as shown in Table 4. Table 5 describes
the equivalent Software Mode, bit se ttings for each of the available formats. Timing diagrams are shown in
Figure 7.
COPY/C ORIG Function
0 0 PRO=0, COPY=0, L=0 copyright
0 1 PRO=0, COPY=0, L=1 copyright, pre-recorded
1 0 PRO=0, COPY=1, L=0 non-copyright
11PRO=1
Table 2. Hardware Mode COPY/C and ORIG Pin Functions
SFMT1 SFMT0 Function
0 0 Serial Input Format IF1 - Left Justified
0 1 Serial Input Format IF2 - I²S
1 0 Serial Input Format IF3 - Right-Justified, 24-bit data
1 1 Serial Input Format IF4 - Right-Justified, 16-bit data
Table 3. Hardware Mode Serial Audio Port Format Selection
HWCK1 HWCK0 Function
0 0 OMCK Frequency is 256*Fs
0 1 OMCK Frequency is 128*Fs
1 0 OMCK Frequency is 512*Fs
1 1 OMCK Frequency is 256*Fs
Table 4. Hardware Mode OMCK Clock Ratio Selection
SISF SIRES1/0 SIJUST SIDEL SISPOL SILRPOL
IF1 - Left Justified 0 00 0 0 0 0
IF2 - I²S 0 00 0 1 0 1
IF3 - Right-Justified, 24-bit data 0 00 1 0 0 0
IF4 - Right-Justified, 16-bit data 0 10 1 0 0 0
Table 5. Equivalent Register Settings of Serial Audio Input Formats in Hardware Mode
DS580F6 29
CS8406
11.PIN DESCRIPTION - HARDWARE MODE
VD 6Digital Power (Input) - Digital core power supply. Typically +3.3 V or +5.0 V.
VL 23 Logic Power (Input) - Input/Output power supply. Typically +3.3 V or +5.0 V.
GND 22 Ground (Input) - Ground for I/O and core logic.
RST 9
Reset (Input) - When RST is low, the CS8406 enters a low power mode and all internal states are reset.
On initial power up, RST must be held low until the power supply is stable, and all input clocks are stable
in frequency and phase. This is particularly true in Hardware Mode with multiple CS8406 devices, where
synchronization between devices is important.
H/S 24
Hardware/Software Control Mode Select (Input) - Determines the method of controlling the operation
of the CS8406, and the method of accessing CS and U data. Hardware Mode provides an alternate
mode of operation, and access to CS and U data is provided by dedicated pins. To select Hardware
Mode, this pin should be permanently tied to VL.
TXN
TXP
25
26
Differential Line Drivers (Output) - These pins transmit biphase encoded data. The drivers are pulled
low while the CS8406 is in the reset state.
OMCK 21 Master Clock (Input) - The frequency can be set through the HWCK[1:0] pins.
ISCLK 13 Serial Audio Bit Clock (Input/Output) - Serial bit clock for audio data on the SDIN pin.
ILRCK 12 Serial Audio Input Left/Right Clock (Input/Output) - Word rate clock for the audio data on the SDIN
pin.
SDIN 14 Serial Audio Data Port (Input) - Audio data serial input pin.
COPY / C ORIG
TEST HWCK1
EMPH TXP
SFMT0 TXN
SFMT1 H/S
VD VL
TEST GND
TEST OMCK
RST HWCK0
APMS AUDIO
TCBLD U
ILRCK V
ISCLK CEN
SDIN TCBL
1
2
3
4
5
6
7
821
22
23
24
25
26
27
28
9
10
11
12 17
18
19
20
13
14 15
16
30 DS580F6
CS8406
SFMT0
SFMT1
4
5
Serial Audio Data Format Select (Input) - Selects the serial audio input port format. See Table 3 on
page 28.
APMS 10 Serial Audio Data Port Master/Slave Select (Input) - APMS should be connected to VL to set serial
audio input port as a master or connected to GND to set the port as a slave.
HWCK0
HWCK1
20
27
OMCK Clock Ratio Select (Input) - Selects the ratio of OMCK to the input sample rate (Fs). A pull-up to
VL or pull-down to GND is required to set the appropriate mode. See Table 4 on page 28.
TCBLD 11 Transmit Channel Status Block Direction (Input) - Connect TCBLD to VL to set TCBL as an output.
Connect TCBLD to GND to set TCBL as an input.
TCBL 15
Transmit Channel Status Block Start (Input/Output) - When operated as output, TCBL is high during
the first sub-frame of a transmitted channel status block, and low at all other times. When operated as
input, driving TCBL high for at least three OMCK clocks will cause the next transmitted sub-frame to be
the start of a channel status block.
CEN 16
C Bit Enable (Input) - Determines how the channel status data bits are input. When CEN is low, Hard-
ware Mode A is selected, where the COPY/C, ORIG, EMPH and AUDIO pins are used to enter selected
channel status data. When CEN is high, Hardware Mode B is selected, where the COPY/C pin is used
to enter serial channel status data.
V17 Validity Bit (Input) - In Hardware Modes A and B, the V pin input determines the state of the validity bit
in the outgoing AES3 transmitted data. This pin is sampled on both edges of the ILRCK.
U18 User Data Bit (Input) - In Hardware Modes A and B, the U pin input determines the state of the user
data bit in the outgoing AES3 transmitted data. This pin is sampled on both edges of the ILRCK.
COPY/C 1
COPY Channel Status Bit/C Bit (Input) - In Hardware Mode A (CEN = 0), the COPY/C and ORIG pins
determine the state of the Copyright, Pro, and L Channel Status bits in the outgoing AES3 data stream,
see Table 2 on page 28. In Hardware Mode B, the COPY/C pin becomes the direct C bit input data pin,
which is sampled on both edges of LRCK.
EMPH 3
Pre-Emphasis Indicator (Input) - In Hardware Mode A (CEN = 0), the EMPH
pin low sets the 3 empha-
sis channel status bits to indicate 50/15 s pre-emphasis of the transmitted audio data. If EMPH is high,
then the three EMPH channel status bits are set to 000, indicating no pre-emphasis.
AUDIO 19 Audio Channel Status Bit (Input) - In Hardware Mode A (CEN = 0), the AUDIO pin determines the
state of the audio/non audio Channel Status bit in the outgoing AES3 data stream.
ORIG 28
ORIG Channel Status Bit Control (Input) - In Hardware Mode A (CEN = 0), the ORIG and COPY/C
pins determine the state of the Copyright, Pro, and L Channel Status bits in the outgoing AES3 data
stream, see Table 2 on page 28.
TEST
2
7
8
Test Pins (Input) - These pins are unused inputs. It is recommended that these pins be tied to a supply
(VL or GND) to minimize leakage current. The CS8406 will operate correctly if these pins are left float-
ing, however current consumption from VL will increase by 25 A per TEST pin that is left floating.
DS580F6 31
CS8406
12.APPLICATIONS
12.1 Reset, Power Down and Start-Up
When RST is low, the CS8406 enters a low power mode and all internal states are reset, including the con-
trol port and registers, and the outputs are disabled. In Software Mode when RST is high, the control port
becomes operational and the desired settings should be loaded into the control registers. Writing a 1 to the
RUN bit will then cause the part to leave the low power state and begin operation. In Hardware Mode when
RST is high, the part will automatically leave the low power state and begin operation.
12.2 ID Code and Revision Code
The CS8406 has a register that contains a four-bit code to indicate that the addressed device is a CS8406.
This is useful when other CS84XX family members are resident in the same or similar systems, allowing
common software modules.
The CS8406 four-bit revision level code is also available. This allows the software driver for the CS8406 to
identify which revision of the device is in a particular system, and modify its behavior accordingly. To allow
for future revisions, it is strongly recommended that the revision code is read into a variable area within the
microcontroller, and used wherever appropriate as revision details become known.
12.3 Power Supply, Grounding, and PCB layout
The CS8406 operates from a VD = +3.3 V or +5.0 V and VL = +3.3 V or +5.0 V supply. These supplied may
be set independently. Follow normal supply decoupling practices, see Figures 5 and 6. The VD and VL sup-
plies should be decoupled with a 0.1 F capacitor to GND to minimize AES3 transmitter induced transients.
Extensive use of power and ground planes, ground plane fill in unused areas and surface mount decoupling
capacitors are recommended. Decoupling capacitors should be mounted on the same side of the board as
the CS8406 to minimize inductance effects, and all decoupling capacitors should be as close to the CS8406
as possible.
12.4 Synchronization of Multiple CS8406s
The AES3 transmitters of multiple CS8406s can be synchronized if all devices share the same master clock,
TCBL, and RST signals. The TCBL pin is used to synchronize multiple CS8406 AES3 transmitters at the
channel status block boundaries. One CS8406 must have its TCBL set to master; the others must be set to
slave TCBL. Alternatively, TCBL can be derived from external logic, whereby all CS8406 devices should be
set to slave TCBL.
32 DS580F6
CS8406
13.PACKAGE DIMENSIONS
INCHES MILLIMETERS
DIM MIN NOM MAX MIN NOM MAX
A 0.093 0.098 0.104 2.35 2.50 2.65
A1 0.004 0.008 0.012 0.10 0.20 0.30
b 0.013 0.017 0.020 0.33 0.42 0.51
C 0.009 0.011 0.013 0.23 0.28 0.32
D 0.697 0.705 0.713 17.70 17.90 18.10
E 0.291 0.295 0.299 7.40 7.50 7.60
e 0.040 0.050 0.060 1.02 1.27 1.52
H 0.394 0.407 0.419 10.00 10.34 10.65
L 0.016 0.026 0.050 0.40 0.65 1.27
µ 0°4°8°0°4°8°
JEDEC #: MS-013
Controlling Dimension is Millimeters
28L SOIC (300 MIL BODY) PACKAGE DRAWING
D
HE
b
A1
A
c
L
SEATING
PLANE
1
e
DS580F6 33
CS8406
Notes:
1. “D” and “E1” are reference datums and do not included mold flash or protrusions, but do include mold
mismatch and are measured at the parting line, mold flash or protrusions shall not exceed 0.20 mm per
side.
2. Dimension “b” does not include da mbar protrusion/intrusion. Allowable dambar protrusion shall be
0.13 mm total in excess of “b” dimension at maximum material condition. Dambar intrusion shall not re-
duce dimension “b” by more than 0.07 mm at least material condition.
3. These dimensions apply to the flat section of the lead between 0.10 and 0.25 mm from lead tips.
INCHES MILLIMETERS NOTE
DIM MIN NOM MAX MIN NOM MAX
A -- --0.47-- --1.20
A1 0.002 0.004 0.006 0.05 0.10 0.15
A2 0.03150 0.035 0.04 0.80 0.90 1.00
b 0.00748 0.0096 0.012 0.19 0.245 0.30 2,3
D 0.378 BSC 0.382 BSC 0.386 BSC 9.60 BSC 9.70 BSC 9.80 BSC 1
E 0.248 0.2519 0.256 6.30 6.40 6.50
E1 0.169 0.1732 0.177 4.30 4.40 4.50 1
e -- 0.026 BSC -- -- 0.65 BSC --
L 0.020 0.024 0.029 0.50 0.60 0.75
µ0°4°8°0°4°8°
JEDEC #: MO-153
Controlling Dimension is Millimeters.
28L TSSOP (4.4 mm BODY) PACKAGE DRAWING
E
N
123
eb2A1
A2 A
D
SEATING
PLANE
E11
L
SIDE VIEW
END VIEW
TOP VIEW
34 DS580F6
CS8406
14.ORDERING INFORMATION
Product Description Pb-Free Package Grade Temp Range Container Order#
CS8406 192 kHz Digital Audio
Transmitter YES
SOIC
Commer-
cial -10º to +70ºC Rail CS8406-CSZ
Tape and Reel CS8406-CSZR
Automotive -40º to +85ºC Rail CS8406-DSZ
Tape and Reel CS8406-DSZR
TSSOP
Commer-
cial -10º to +70ºC Rail CS8406-CZZ
Tape and Reel CS8406-CZZR
Automotive -40º to +85ºC Rail CS8406-DZZ
Tape and Reel CS8406-DZZR
CDB8416 CS8406 & CS8416 Evaluation
Board - - - - CDB8416
DS580F6 35
CS8406
15.APPENDIX A: EXTERNAL AES3/SPDIF/IEC60958 TRANSMITTER
COMPONENTS
This section details the external components required to interface the AES3 transmitter to cables and fiber-optic
components.
15.1 AES3 Transmitter External Components
The output drivers on the CS8406 are designed to drive both the professional and consumer interfaces. The
AES3 and IEC60958-4 specifications call for a balanced output drive of 2-7 V peak-to-peak into a 110 ±
20% load with no cable attached. Using the circuit in Figure 14, the output of the transformer is short-circuit
protected, has the p roper source impedance, and provides a 5 V peak-to-peak signal into a 110 load.
Lastly, the two output pins should be attached to an XLR connector with male pins and a female shell, and
with pin 1 of the connector grounded.
In the case of consumer use, the IEC60958-3 specification calls for an unbalanced drive circuit with an out-
put impedance of 75 ± 20% and a output drive level of 0.5 V peak-to-peak ± 20% when measured across
a 75 load using no cable. The circuit shown in Figure 15 only uses the TXP pin and provides the proper
output impedance and drive level using standard 1% resistors. If VL is set to +3.3 V, change 374 to 243
and change 90.9 to 107 . The connector for a consumer application would be an RCA phono socket.
This circuit is also short circuit protected.
The TXP pin may be used to drive TTL or CMOS gates as shown in Figure 16. This circuit may be used for
optical connectors for digital audio since they usually have TTL or CMOS compatible inputs. This circuit is
also useful when driving multiple digital audio outputs since RS422 line drivers have TTL compatible inputs.
15.2 Isolating Transformer Requirements
Please refer to the application note AN134: AES and SPDIF Recommended Transformers for resources on
transformer selection.
374-RTXP
90.9
TXP
TXN
RCA
Phono
CS8406
110-(RTXP+RTXN)
TXP
TXN
XLR
Pin 1
CS8406
Figure 14. Professional Output Circuit Figure 15. Consumer Output Circuit (VL = 5.0 V)
TXP
TXN
TTL or
CMOS Gate
CS8406
Figure 16. TTL/CMOS Output Circuit
36 DS580F6
CS8406
16.APPENDIX B: CHANNEL STATUS AND USER DATA BUFFER
MANAGEMENT
The CS8406 has a comprehensive channel status (C) and user (U) data buffering scheme which allows the user to
manage the C and U data through the control port.
16.1 AES3 Channel Status(C) Bit Management
The CS8406 contains sufficient RAM to store a full block of C data for both A and B channels (192x2 = 384
bits), and also 384 bits of U information. The user may read from or write to these RAM buffers through the
control port.
The CS8406 manages the flow of channel status data at the block level, meaning that entire blocks of chan-
nel status information are buffered at the input, synchronized to the output timebase, and then transmitted.
The buffering scheme involves a cascade of 2 block-sized buffers, named E and F, as shown in Figure 17.
The MSB of each byte represents the first bit in the serial C data stream. For example, the MSB of byte 0
(which is at control port address 20h) is the consumer/professional bit for channel status block A.
The E buffer is accessible from the control port, allowing read and writing of the C data. The F buffer is used
as the source of C data for the AES3 transmitter. The F buffer accepts block transfers from the E buffer.
16.1.1 Accessing the E buffer
The user can monitor the data being transferred by reading the E buffer, which is mapped into the register
space of the CS8406, through the control port. The user can modify the data to be transmitted by writing
to the E buffer.
The user can configure the interrupt enable register to cause interrupts to occur whenever “E to F” buffer
transfers occur. This allows determination of the allowable time periods to interact with the E buffer.
Also provided is an “E to F” inhibit bit. The “E to F” buffer transfer is disabled whenever the user sets this
bit. This may be used whenever “long” control port interactions are occurring.
A flowchart for reading and writing to the E buffer is shown in Figure 18. For writing, the sequence starts
after a E to F transfer, which is based on the output timebase.
If the channel status block to transmit indicates PRO Mode, then the CRCC byte is automatically calcu-
lated by the CS8406, and does not have to be written into the last byte of the block by the host microcon-
Control Port
To
AES3
Transmitter
E
24
words
8-bits 8-bits
AB
F
Transmit
Data
Buffer
Figure 17. Channel Status Data Buffer Structure
DS580F6 37
CS8406
troller. This is also true if the channel status data is entered serially through the COPY/C pin when the part
is in Hardware Mode.
16.1.2 Serial Copy Management System (SCMS)
In Software Mode, the CS8406 allows read/modify/write access to all the channel status bits. For Con-
sumer Mode SCMS compliance, the host microcontroller needs to manipulate the Category Code, Copy
bit and L bit appropriately.
In Hardware Mode, the SCMS protocol can be followed by either using the COPY and ORIG input pins,
or by using the C bit serial input pin. These options are documented in the Hardware Mode section of this
data sheet.
16.1.3 Channel Status Data E Buffer Access
The E buffer is organized as 24 x 16-bit words. For each word the MS Byte is the A channel data, and the
LS Byte is the B channel data (see Figure 17).
There are two methods of accessing this memory, known as One-Byte Mode and Two-Byte Mode. The
desired mode is selected through a control register bit.
16.1.3.1 One-Byte Mode
In many applications, the channel status blocks for the A and B channels will be identical. In this situation,
if the user reads a byte from one of the channel's blocks, the corresponding byte for the other channel will
be the same. Similarly, if the user wrote a byte to one channel's block, it would be necessary to write the
same byte to the other block. One-Byte Mode takes advantage of the often identical nature of A and B chan-
nel status data.
When reading data in One-Byte Mode, a single byte is returned, which can be from channel A or B data,
depending on a register control bit. If a write is being done, the CS8406 expects a single byte to be input
to its control port. This byte will be written to both the A and B locations in the addressed word.
One-Byte Mode saves the user substantial control port access time, as it effectively accesses 2 bytes worth
of information in 1 byte's worth of access time. If th e control port's auto increment addressing is used in
combination with this mode, multi-byte accesses such as full-block reads or writes can be done especially
efficiently.
EtoFinterruptoccurs
Optionally set E to F inhibit
If set, clear E to F inhibit
Return
Write E data
Wait for E to F transfer
Figure 18. Flowchart for Writing the E Buffer
38 DS580F6
CS8406
16.1.3.2 Two-Byte Mode
There are those applications in which the A and B channel status blocks will not be the same, and the user
is interested in accessing both blocks. In these situations, Two-Byte Mode should be used to access the E
buffer.
In this mode, a read will cause the CS8406 to output two bytes from its control port. The first byte out will
represent the A channel status data, and the 2nd byte will represent the B channel status data. Writing is
similar, in that two bytes must now be input to the CS8406's control port. The A channel status data is first;
B channel status data second.
16.2 AES3 User (U) Bit Management
The CS8406 U bit manager has two operating modes:
Mode 1. Transmit all zeros.
Mode 2. Block mode.
16.2.1 Mode 1: Transmit All Zeros
Mode 1 causes only zeros to be transmitted in the output U data, regardless of E buffer contents. This
mode is intended for the user who wants the output U channel to contain no data.
16.2.2 Mode 2: Block Mode
Mode 2 is very similar to the scheme used to control the C bits. Entire blocks of U data are buffered using
2 block-sized RAMs to perform the buffering. The user has access to the first buffer, denoted the E buffer,
through the control port. It is the only mode in which the user can merge his own U data into the transmit-
ted AES3 data stream. The U buffer access only operates in Two-Byte Mode, since there is no concept
of A and B blocks for user data. The ar rangement of the data is as followings: Bit15[A7] Bit14[B7]
Bit13[A6] Bit12 [B6]...Bit1 [A0] Bit0[B0]. The arrangement of the data in the each byte is that the MSB is
the first transmitted bit. The bit for the A subframe is followed by the bit for the B subframe.
DS580F6 39
CS8406
17.REVISION HISTORY
Release Date Changes
F3 July 2005 -Updated Packaging Information to include Lead Free devices and updated “Table of
Contents” on page 2.
F4 April 2006
-Removed references to “Autoincrement” feature in “Control Port Description” on
page 16. Indicated that the MAP will always increment.
-Corrected definition of pin 5 in “Pin Description - Software Mode” on page 25.
F5 October 2009
- Added QFN package option to “General Description” on page 1, “Package Dimen-
sions” on page 32, and “Ordering Information” on page 34.
- Added QFN pin-out drawing and thermal pad description to “Pin Description - Software
Mode” on page 25 and “Pin Description - Hardware Mode” on page 30.
- Added QFN thermal pad guidelines to “Power Supply, Grounding, and PCB layout” on
page 33.
F6 Aug 2012 Removed QFN package options listed in F5 (reverted content to F4 release).
Contacting Cirrus Logic Support
For all product questions and inquiries, contact a Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com
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