ETC CS8412-CS

CS8411 CS8412
Semiconductor Corporation
Digital Audio Interface Receiver
Features
General Description:
• Monolithic CMOS Receiver
• Low-Jitter, On-Chip Clock Recovery
The CS8411/12 are monolithic CMOS devices which receive and decode audio data according to the
AES/EBU, IEC 958, S/PDIF, & EIAJ CP-340 interface
standards. The CS8411/12 receive data from a transmission line, recover the clock and synchronization
signals, and de-multiplex the audio and digital data. Differential or single ended inputs can be decoded.
256×Fs Output Clock Provided
AES/EBU, IEC 958,
• Supports:
S/PDIF, & EIAJ CP-340
Professional and Consumer Formats
Error Reporting
• Extensive
Repeat Last Sample on Error Option
• On-Chip RS422 Line Receiver
• Configurable Buffer Memory (CS8411)
VD+
7
CS8411
RXP
RXN
DGND
8
FILT
VA+
The CS8412 de-multiplexes the channel, user, and validity data directly to serial output pins with dedicated
output pins for the most important channel status bits.
ORDERING INFORMATION:
TABLE OF CONTENTS:
AGND
20
22
The CS8411 has a configurable internal buffer memory,
read via a parallel port, which may be used to buffer
channel status, auxiliary data, and/or user data.
MCK
21
19
26
Audio
Serial Port
13
RS422
Receiver
10
Clock & Data
Recovery
VD+
DGND
7
CS8412
8
FILT
VA+
20
22
19
Clock & Data
Recovery
D7- D0
24
CS
23
RD/WR
26
12
11
SDATA
SCK
M3 M2 M1 M0
17 18 24 23
Audio
Serial Port
RS422
Receiver
8
INT
9
10
1
Mux
14
28
CS12/
FCK
Preliminary Product Information
Crystal Semiconductor Corporation
P.O. Box 17847, Austin, TX 78760
(512) 445-7222 FAX: (512) 445-7581
Mux
16
SEL
FSYNC
De-Mux
Registers
13
A4/FCK
14
ERF
MCK
21
SCK
FSYNC
A3 - A0
Configurable
Buffer
Memory
AGND
SDATA
4
De-Mux
25
RXN
12
11
9
IEnable & Status
RXP
page 33
page 34
6
5
4
C0/ Ca/ Cb/ Cc/
E0 E1 E2 F0
3
2
Cd/
F1
27
Ce/
F2
25
ERF
C
U
VERF
15
CBL
This document contains information for a new product. Crystal
Semiconductor reserves the right to modify this product without notice.
NOV ’93
DS61PP4
1
CS8411 CS8412
ABSOLUTE MAXIMUM RATINGS (GND = 0V, all voltages with respect to ground)
Parameter
Symbol
Power Supply Voltage
Input Current, Any Pin Except Supply
Max
Units
VD+, VA+
6.0
V
Iin
±10
mA
Note 1
Min
Input Voltage, Any Pin except RXP, RXN
VIN
-0.3
VD+ + 0.3
V
Input Voltage, RXP and RXN
VIN
-12
12
V
Ambient Operating Temperature (power applied)
TA
-55
125
°C
Tstg
-65
150
°C
Storage Temperature
Notes:
1. Transient currents of up to 100 mA will not cause SCR latch-up.
WARNING: Operation beyond these limits may result in permanent damage to the device.
Normal operation is not guaranteed at these extremes.
RECOMMENDED OPERATING CONDITIONS
(GND = 0V; all voltages with respect to ground)
Parameter
Power Supply Voltage
Supply Current
Symbol
Min
Typ
Max
Units
VD+, VA+
4.5
5.0
5.5
V
20
7
35
10
mA
mA
VA+
VD+
IA
ID
Ambient Operating Temperature: CS8411/12-CP or -CS Note 2
TA
CS8411/12-IP or -IS
Power Consumption
Notes:
0
70
°C
85
°C
248
mW
25
-40
PD
135
2. The ’-CP’ and ’-CS’ parts are specified to operate over 0 to 70 °C but are tested at 25 °C only.
The ’-IP’ and ’-IS’ parts are tested over the full -40 to 85 °C temperature range.
DIGITAL CHARACTERISTICS
(TA = 25 °C for suffixes ’-CP’ & ’-CS’, TA = -40 to 85 °C for ’-IP’ & ’-IS’; VD+, VA+ = 5V ± 10%)
Parameter
Symbol
Min
2.0
High-Level Input Voltage
except RXP, RXN
VIH
Low-Level Input Voltage
except RXP, RXN
VIL
High-Level Output Voltage
(IO = 200µA)
VOH
Low-Level Output Voltage
(IO = -3.2mA)
VOL
Input Leakage Current
Master Clock Frequency
CS8411/12-CP or -CS
CS8411/12-IP or -IS
Note 3
MCK Clock Jitter
25
30
MCK
6.4
tj
V
V
1.0
FS
FS
Units
V
VD+ - 1.0
MCK Duty Cycle (high time/cycle time)
Notes:
Max
+0.8
Iin
Input Sample Frequency (Note 3)
Typ
256×FS
0.4
V
10
µA
55
50
kHz
kHz
14.08
MHz
200
ps RMS
50
%
3. FS is defined as the incoming audio sample frequency per channel.
Specifications are subject to change without notice.
2
DS61PP4
CS8411 CS8412
DIGITAL CHARACTERISTICS - RS422 RECEIVERS
(RXP, RXN pins only; VD+, VA+ = 5V ± 10%)
Parameter
Input Resistance
Symbol
(-7V < VCM < 7V)
Note 4
ZIN
Differential Input Voltage, RXP to RXN (-7V < VCM < 7V) Note 4,5
VTH
Input Hysteresis
Notes:
Min
Typ
Max
10
Units
kΩ
200
mV
VHYST
50
mV
4. VCM - Input Common Mode Range
5. When the receiver inputs are configured for single ended operation (e.g. consumer configuration) the signal
amplitude must exceed 400mVp-p for the differential voltage on RXP to RXN to exceed 200mV. This represents
SWITCHING CHARACTERISTICS - CS8411 PARALLEL PORT
(TA = 25 °C for suffixes ’-CP’ and ’-CS’; TA = -40 to 85 °C for suffixes ’-IP’ and ’-IS’;
VD+, VA+ = 5V ± 10%; Inputs: Logic 0 = DGND, logic 1 = VD+; CL = 20 pF)
Parameter
Symbol
Min
ADDRESS valid to CS low
tadcss
13.5
ns
CS high to ADDRESS invalid
tcsadh
0
ns
RD/WR valid to CS low
trwcss
10
ns
CS low to RD/WR invalid
tcsrwi
35
ns
tcsl
35
ns
CS low
Typ
Max
Units
DATA valid to CS rising
RD/WR low (writing)
tdcssw
32
ns
CS high to DATA invalid
RD/WR low (writing)
tcsdhw
0
ns
CS falling to DATA valid
RD/WR high (reading)
tcsddr
CS rising to DATA Hi-Z
RD/WR high (reading)
tcsdhr
35
5
ns
ns
A4 - A0
t adcss
t csadh
CS
t csl
t rwcss
t csrwi
RD/WR
Writing
t dcssw
t csdhw
D7 - D0
RD/WR
Reading
t csddr
t csdhr
D7 - D0
CS8411 Parallel Port Timing
DS61PP4
3
CS8411 CS8412
SWITCHING CHARACTERISTICS - SERIAL PORTS
(TA = 25 °C for suffixes ’-CP’ and ’-CS’; TA = -40 to 85 °C for suffixes ’-IP’ and ’-IS’;
VD+, VA+ = 5V ± 10%; Inputs: Logic 0 = DGND, logic 1 = VD+; CL = 20 pF)
Parameter
SCK Frequency
Symbol
Master Mode
Notes 5,6
Slave Mode
SCK falling to FSYNC delay
Master Mode
SCK Pulse Width Low
SCK Pulse Width High
Min
fsck
Typ
Max
OWR×32
Note 6
OWR×32
Units
Hz
TBD
Hz
20
ns
Notes 6,7
tsfdm
-20
Slave Mode
Note 6
tsckl
40
ns
Slave Mode
Note 6
tsckh
40
ns
SCK rising to FSYNC edge delay Slave Mode
Notes 6,7
tsfds
20
ns
FSYNC edge to SCK rising setup Slave Mode
Notes 6,7
tfss
20
ns
Note 7
tssv
SCK falling (rising) to SDATA valid
C, U, CBL valid to FSYNC edge
CS8412
MCK to FSYNC edge delay
FSYNC from RXN/RXP
Notes:
Note 7
20ns
tcuvf
1/fsck
s
tmfd
15
ns
5. The output word rate, OWR, refers to the frequency at which an audio sample is output from the part.
(A stereo pair is two audio samples.) Therefore, in Master mode, there are always 32 SCK periods
in one audio sample. In Slave mode 32 SCK periods must be provided in most serial port formats.
6. In master mode SCK and FSYNC are outputs. In Slave mode they are inputs. In the CS8411, control
reg. 2 bit 1, MSTR, selects master. In the CS8412, formats 1 & 3 are slaves.
7. The table above assumes data is output on the falling edge and latched on the rising edge. With both
parts the edge is selectable. The table is defined for the CS8411 with control reg. 2 bit 0, SCED, set
to one, and for the CS8412 in formats 2, 3, 5 - 7. For the other formats, the table and figure edges
must be reversed (i.e.. "rising" to "falling" and vice versa).
FSYNC
t sfds
t fss
t sckl t sckh
MCK
t mfd
SCK
FSYNC
t ssv
FSYNC Generated From Received Data
SDATA
MSB
C, U
Mode 1
t cuvf
FSYNC
FSYNC
t sfds
t fss
t sckl t sckh
t sfdm
t sckf
SCK
SCK
t ssv
t ssv
SDATA
MSB
SDATA
Mode 3
Serial Output Timing - Slave Mode
4
Serial Output Timing - Master Mode & C, U Port
DS61PP4
CS8411 CS8412
+5V digital
+5V analog
0.1 uF
0.1 uF
9
Receiver
Circuit
19
FSYNC
SCK
SDATA
11
12
26
ERF
25
INT
14
CS
24
RD/WR
23
RXP
CS8411
10
(See Appendix A)
MCK
VD+
VA+
AGND
21
RXN
20
5k
7
22
FILT
A0 - A4
1k
DGND
0.047 uF
Audio
Data
Processor
Audio
Data
Processor
or
Microcontroller
D0 - D7
8
Figure 1. CS8411 Typical Connection Diagram
+5V digital
+5V analog
0.1 uF
22
0.1 uF
21
Receiver
Circuit
(See Appendix A)
9
10
13
Channel Status
and/or
Error/Frequency
Reporting
16
25
7
MCK
19
RXP
VERF
SCK
SDATA
28
12
26
FSYNC
11
RXN
VA+
AGND
VD+
CS8412
CS12/FCK
SEL
ERF
6 C / E-F bits
20
1k
FILT
Audio
Data
Processor
C
1
U
14
CBL
15
Microcontroller
or
Logic
DGND
8
0.047 uF
Figure 2. CS8412 Typical Connection Diagram
DS61PP4
5
CS8411
GENERAL DESCRIPTION
The CS8411/12 are monolithic CMOS circuits
that receive and decode audio and digital data according to the AES/EBU, IEC 958, S/PDIF, and
EIAJ CP-340 interface standards. Both chips contain RS422 line receivers and Phase-Locked
Loops (PLL) that recover the clock and synchronization signals, and de-multiplex the audio and
digital data. The CS8411 contains a configurable
internal buffer memory, read via a parallel port,
which can buffer channel status, user, and optionally auxiliary data. The CS8412 de-multiplexes
the channel status, user, and validity information
directly to serial output pins with dedicated pins
for the most important channel status bits. Both
chips also contain extensive error reporting as
well as incoming sample frequency indication for
auto-set applications.
Familiarity with the AES/EBU and IEC 958
specifications are assumed throughout this document. The App Note, Overview of Digital Audio
Interface Data Structures, contains information on
digital audio specifications; however, it is not
meant to be a complete reference. To guarantee
compliance, the proper standards documents
should be obtained. The AES/EBU standard,
AES3-1985, should be obtained from the Audio
Engineering Society or ANSI (ANSI document #
ANSI S4.40-1985); the IEC 958 standard from
the International Electrotechnical Commission;
and the EIAJ CP-340 standard from the Japanese
Electronics Bureau.
Line Receiver
The RS422 line receiver can decode differential
as well as single ended inputs. The receiver consists of a differential input Schmitt trigger with
50mV of hysteresis. The hysteresis prevents noisy
signals from corrupting the phase detector. Appendix A contains more information on how to
configure the line receivers for differential and
single ended signals.
6
Clocks and Jitter Attenuation
The primary function of these chips is to recover
audio data and low jitter clocks from a digital
audio transmission line. The clocks that can be
generated are MCK (256×FS), SCK (64×FS), and
FSYNC (FS or 2×FS). MCK is the output of the
voltage controlled oscillator which is a component of the PLL. The PLL consists of phase and
frequency detectors, a second-order loop filter,
and a voltage controlled oscillator. All components of the PLL are on chip with the exception
of a resistor and capacitor used in the loop filter.
This filter is connected between the FILT pin and
AGND. The closed-loop transfer function, which
specifies the PLL’s jitter attenuation characteristics, is shown in Figure 3. The loop will
begin to attenuate jitter at approximately 25 kHz
with another pole at 80 kHz, and will have 50 dB
of attenuation by 1MHz. Since most data jitter introduced by the transmission line is high in
frequency, it will be strongly attenuated.
Multiple frequency detectors are used to minimize the time it takes the PLL to lock to the
incoming data stream and to prevent false lock
conditions. When the PLL is not locked to the incoming data stream, the frequency detectors pull
the VCO frequency within the lock range of the
PLL. When no digital audio data is present, the
VCO frequency is pulled to its minimum value.
As a master, SCK is always MCK divided by
four, producing a frequency of 64×FS. In the
CS8411, FSYNC can be programmed to be a divided version of MCK or it can be generated
directly from the incoming data stream. In the
CS8412, FSYNC is always generated from the incoming data stream. When FSYNC is generated
from the data, its edges are extracted at times
when intersymbol interference is at a minimum.
This provides a sample frequency clock that is as
spectrally pure as the digital audio source clock
for moderate length transmission lines. For long
transmission lines, the CS8411 can be pro-
DS61PP4
CS8411
0 dB
Jitter Attenuation
25dB
50dB
75dB
100dB
1kHz
10kHz
100kHz
1MHz
10MHz
Jitter Frequency
Figure 3. Jitter Attenuator Characteristics
grammed to generate FSYNC from MCK instead
of from the incoming data.
CS8411 DESCRIPTION
The CS8411 is more flexible than the CS8412 but
requires a microcontroller or DSP to load internal
registers. The CS8412 does not have internal registers so it may be used in a stand-alone mode
where no microprocessor or DSP is available.
The CS8411 accepts data from a transmission
line coded according to the digital audio interface
standards. The I.C. recovers clock and data, and
separates the audio data from control information.
The audio data is output through a configurable
serial port and the control information is stored in
internal dual-port RAM. Extensive error reporting
is available via internal registers with the option
of repeating the last sample when an error occurs.
A block diagram of the CS8411 is shown in Figure 4
Parallel Port
The parallel port accesses two status registers,
two interrupt enable registers, two control registers, and 28 bytes of dual-port buffer memory.
The status registers and interrupt enable registers
DS61PP4
occupy the same address space. A bit in control
register 1 selects the two registers, either status or
interrupt enable, that occupy addresses 0 and 1 in
the memory map. The address bus and the
RD/WR line should be valid when CS goes low.
If RD/WR is low, the value on the data bus will
be written into the buffer memory at the specified
address. If RD/WR is high, the value in the buffer
memory, at the specified address, is placed on the
data bus. Detailed timing for the parallel port can
be found in the Switching Characteristics - Parallel Port table.
The memory space on the CS8411 is allocated as
shown in Figure 5. There are three defined buffer
modes selectable by two bits in control register 1.
Further information on the buffer modes can be
found in the Control Registers section.
Status and IEnable Registers
The status and interrupt enable registers occupy
the same address space. The IER/SR bit in control
register 1 selects whether the status registers
(IER/SR = 0) or the IEnable registers (IER/SR =
1) occupy addresses 0 and 1. Upon power-up, the
control and IEnable registers contain all zeros;
therefore, the status registers are visible and all
interrupts are disabled. The IER/SR bit must be
set to make the IEnable registers visible.
7
CS8411
VA+
22
FILT AGND
20
21
MCK
19
11
Bi-phase
Decoder
Audio
Serial
Port
9
RXP
RXN
Clock & Data
Recovery
26
De-Multiplexor
SCK
SDATA
10
Confidence
Flag
Control
Registers
2X8
crc
check
aux
7
user
Buffer
Memory
8
C.S.
28 X 8
VD+
DGND
12
FSYNC
slipped
parity
validity
crc
coding
no lock
confidence
14
25
IEnable
&
Status
24
23
4X8
Frequency
Comparator
4
INT
ERF
CS
RD/WR
8
13
A4/ A0FCK A3
D0D7
Figure 4. CS8411 Block Diagram
Status register 1 (SR1), shown in Figure 6, reports all the conditions that can generate a pulse
of four SCLK cycles on the interrupt pin (INT).
The three least significant bits, FLAG2-FLAG0,
are used to monitor the ram buffer. These bits
continually change and indicate the position of
the buffer pointer which points to the buffer
memory location currently being written. Each
flag has a corresponding interrupt enable bit in
IEnable register 1 which, when set, allows a transition on the flag to generate a pulse on the
interrupt pin. FLAG0 and FLAG1 cause interrupts on both edges whereas FLAG2 causes an
interrupt on the rising edge only. Further information, including timing, on the flags can be found
in the Buffer Memory section.
8
The next five bits; ERF, SLIP, CCHG,
CRCE/CRC1, and CSDIF/CRC2, are latches
which are set when their corresponding conditions occur, and are reset when SR1 is read.
Interrupt pulses are generated the first time that
condition occurs. If the status register is not read,
further instances of that same condition will not
generate another interrupt. ERF is the error flag
bit and is set when the ERF pin goes high. It is an
OR’ing of the errors listed in status register 2,
bits 0 through 4, AND’ed with their associated interrupt enable bits in IEnable register 2.
SLIP is only valid when the audio port is in slave
mode (FSYNC and SCK are inputs to the
CS8411). This flag is set when an audio sample is
dropped or reread because the audio data output
from the part is at a different frequency than the
DS61PP4
CS8411
data received from the transmission line. CCHG
is set when any bit in channel status bytes 0
through 3, stored in the buffer, changes from one
block to the next. In buffer modes 0 and 1, only
one channel of channel status data is buffered, so
CCHG is on ly affected b y that channel.
(CS2/CS1 in CR1 selects which channel is buffered.) In buffer mode 2 both channels are
buffered, so both channels affect CCHG. This bit
is updated after each byte (0 to 3) is written to the
buffer. The two most significant bits in SR1,
CRCE/CRC1 and CSDIF/CRC2, are dual function flags. In buffer modes 0 and 1, they are
CRCE and CSDIF, and in buffer mode 2, they are
A
D
D
R
E
S
S
0
Status 1 / IEnable 1
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
10
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F
Status 2 / IEnable 2
Control Register 1
Control Register 2
User Data
1st Four
Bytes of
C. S. Data
1st Four
Bytes of
C. S. Data
1st Four
Bytes of
Left C. S.
Data
C. S.
Data
Left
C. S.
Data
Last
20 Bytes
Channel
Status
Data
U
N
D
E
F
I
N
E
D
1st Four
Bytes of
Right
C. S. Data
Auxiliary
Data
CRC1 and CRC2. In buffer modes 0 and 1, the
channel selected by the CS2/CS1 bit is stored in
RAM and CRCE indicates that a CRC error occurred in that channel. CSDIF is set if there is any
difference between the channel status bits of each
channel. In buffer mode 2 channel status from
both channels is buffered, with CRC1 indicating a
CRC error in channel 1 and CRC2 indicating a
CRC error in channel 2. CRCE, CRC1, and
CRC2 are updated at the block boundary. Block
boundary violations also cause CRC1,2 or CRCE
to be set.
IEnable register 1, which occupies the same address space as status register 1, contains interrupt
enable bits for all conditions in status register 1.
A "1" in a bit location enables the same bit location in status register 1 to generate an interrupt
pulse. A "0" masks that particular status bit from
causing an interrupt.
Status register 2 (SR2) reports all the conditions
that can affect the error flag bit in SR1 and the
error pin (ERF), and can specify the received
clock frequency. As previously mentioned, the
first five bits of SR2 are AND’ed with their interrupt enable bits (in IER2) and then OR’ed to
create ERF. The V, PARITY, CODE, LOCK, and
7
6
5
CSDIF/ CRCE/
CCHG
SR1
CRC2 CRC1
X:00
4
3
SLIP
ERF
2
1
0
FLAG2 FLAG1 FLAG0
IER1
INTERRUPT ENABLE BITS FOR ABOVE
SR1:
CSDIF: CS different between sub-frames. Buf. modes 0 & 1.
CRC2: CRC Error - sub-frame 2. Buffer mode 2 only.
CRCE: CRC Error - selected sub-frame. Buffer modes 0 & 1.
CRC1: CRC Error - sub-frame 1. Buffer mode 2 only.
CCNG: Channel Status changed
SLIP: Slipped an audio sample
ERF: Error Flag. ORing of all errors in SR2.
FLAG2: High for first four bytes of channel status
FLAG1: Memory mode dependent - See Figure 11
FLAG0: High for last two bytes of user data.
Right
C. S.
Data
IER1:
Enables the corresponding bit in SR1.
A "1" enables the interrupt. A "0" masks the interrupt.
0
1
2
3
Memory Mode
Figure 5. CS8411 Buffer Memory Map
DS61PP4
Figure 6. Status/IEnable Register 1
9
CS8411
CONF bits are latches which are set when their
corresponding conditions occur, and are reset
when SR2 is read. The ERF pin is asserted each
time the error occurs assuming the interrupt enable bit in IER2 is set for that particular error.
When the ERF pin is asserted, the ERF bit in SR1
is set. If the ERF bit was not set prior to the ERF
pin assertion, an interrupt will be generated (assuming bit 3 in IER1 is set). Although the ERF
pin is asserted for each occurrence of an enabled
error condition, the ERF bit will only cause an
interrupt once if SR1 is not read.
V is the validity status bit which is set any time
the received validity bit is high. PARITY is set
when a parity error is detected. CODE is set when
a biphase coding error is detected. LOCK is asserted when the receiver PLL is not locked and
occurs when there is no input on RXP/RXN, or if
the received frequency is out of the receiver lock
range (25 kHz to 55 kHz). Lock is achieved after
receiving three frame preambles followed by one
block preamble, and is lost after four consecutive
frame preambles are not received. CONF is the
confidence flag which is asserted when the received data eye opening is less than half a bit
period. This indicates the transmission link is
poor and does not meet specifications.
The upper three bits in SR2, FREQ2-FREQ0, can
report the receiver frequency when the receiver is
locked. These bits are only valid when FCEN in
control register 1 is set, and a 6.144 MHz clock is
applied to the FCK pin. When FCEN is set, the
A4/FCK pin is used as FCK and A4 is internally
set to zero; therefore, only the lower half of the
buffer can be accessed. Table 2 lists the frequency
ranges reported. The FREQ bits are updated three
times per block and the clock on the FCK pin
must be valid for two thirds of a block for the
FREQ bits to be accurate. The vast majority of
audio systems must meet the 400 ppm tolerance
listed in the table. The 4% tolerance is provided
for unique situations where the approximate frequency needs to be known, even though that
frequency is outside the normal audio specifications.
IEnable register 2 has corresponding interrupt enable bits for the first five bits in SR2. A "1"
enables the condition in SR2 to cause ERF to go
high, while a "0" masks that condition. Bit 5 is
unused and bits 6 and 7, the two most significant
bits, are factory test bits and must be set to zero
when writing to this register. The CS8411 sets
these bits to zero on power-up.
Control Registers
X:01
7
6
5
4
SR2 FREQ2 FREQ1 FREQ0 CONF
IER2 TEST1 TEST0
3
LOCK
2
1
CODE PARITY
INT. ENABLE BITS FOR ABOVE
SR2:
FREQ2: The 3 FREQ bits indicate incoming sample freq.
FREQ1:
(must have 6.144 MHz clock on FCK pin
FREQ0:
and FCEN must be "1")
CONF: Confidence error
LOCK: Out-of-Lock error
CODE: Coding violation
PARITY: Parity error
V: Validity bit high
IER2:
TEST1,0: (0 on power-up) Must stay at "0".
INT. ENABLES: Enables the corresponding bit in SR2.
A "1" enables the interrupt. A "0" masks the interrupt.
Figure 7. Status/IEnable Register 2
10
0
V
The CS8411 contains two control registers. Control register 1 (CR1), at address 2, selects system
level features, while control register 2 (CR2), at
address 3, configures the audio serial port.
In control register 1, when RST is low, all outputs
are reset except MCK (FSYNC and SCLK are
high impedance). After the user sets RST high,
the CS8411 comes fully out of reset when the
block boundary is found. The serial port, in master mode, will begin to operate as soon as RST
goes high. B0 and B1 select one of three buffer
modes listed in Table 1 and illustrated in Figure 5.
In all modes four bytes of user data are stored. In
mode 0, one entire block of channel status is
stored. In mode 1 eight bytes of channel status
DS61PP4
CS8411
and sixteen bytes of auxiliary data are stored. In
mode 2, eight bytes of channel status from each
sub-frame are stored. The buffer modes are discussed in more detail in the Buffer Memory
section. The next bit, CS2/CS1, selects the particular sub-frame of channel status to buffer in
modes 0 and 1, and has no effect in mode 2.
When CS2/CS1 is low, sub-frame 1 is buffered,
and when CS2/CS1 is high, sub-frame 2 is buffered. IER/SR selects which set of registers, either
IEnable or status, occupy addresses 0 and 1.
When IER/SR is low, the status registers occupy
the first two addresses, and when IER/SR is high,
the IEnable registers occupy those addresses.
FCEN enables the internal frequency counter. A
6.144 MHz clock must be connected to the FCK
pin as a reference. The value of the FREQ bits in
SR2 are not valid until two thirds of a block of
data is received. Since FCK and A4, the most significant address bit, occupy the same pin, A4 is
internally set to zero when FCEN is high. Since
A4 is forced to zero, the upper half of the buffer
is not accessible while using the frequency compare feature. FPLL determines how FSYNC is
derived. When FPLL is low, FSYNC is derived
7
6
5
4
X:02
CR1 FPLL FCEN IER/SR CS2/CS1
3
B1
2
B0
1
0
RST
FPLL: 0 - FSYNC from RXP/RXN, 1 - FSYNC from PLL
FCEN: enables freq. comparator (FCK must be 6.144 MHz).
IER/SR: [X:00,01] 0 - status, 1 - interrupt enable registers.
CS2/CS1: ch. status to buffer; 0 - sub-frame 1, 1 - sub-frame 2.
B1: with B0, selects the buffer memory mode.
B0: with B1, selects the buffer memory mode.
RST: Resets internal counters. Set to "1" for normal operation.
Figure 8. Control Register 1
from the incoming data, and when FPLL is high,
it is derived from the internal phase-locked loop.
Control Register 2 configures the serial port
which consists of three pins: SCK, SDATA, and
FSYNC. SDATA is always an output, but SCK
and FSYNC can be configured as inputs or outputs. FSYNC and SDATA can have a variety of
relationships to each other, and the polarity of
SCK can be controlled. The large variety of audio
data formats provides an easy interface to most
DSPs and other audio processors. SDATA is normally just audio data, but special modes are
provided that output received biphase data, or received NRZ data with zeros substituted for
preamble. Another special mode allows an asynchronous SCK input to read audio data from the
serial port without slipping samples. In this mode
FSYNC and SDATA are outputs synchronized to
the SCK input. Since SCK is asynchronous to the
received clock, the number of SCK cycles between FSYNC edges will vary.
7
6
5
4
3
2
1
0
X:03
CR2 ROER SDF2 SDF1 SDF0 FSF1 FSF0 MSTR SCED
ROER: Repeat previous value on error (audio data)
SDF2: with SDF0 & SDF1, select serial data format.
SDF1: with SDF0 & SDF2, select serial data format.
SDF0: with SDF1 & SDF2, select serial data format.
FSF1: with FSF0, select FSYNC format.
FSF0: with FSF1, select FSYNC format.
MSTR: When set, SCK and FSYNC are outputs.
SCED: When set, falling edge of SCK outputs data.
When clear, rising edge of SCK outputs data.
Figure 9. Control Register 2
FREQ2 FREQ1 FREQ0
Sample Frequency
0
0
0
Out of Range
0
0
1
48kHz ± 4%
B1
B0
Mode
Buffer Memory Contents
0
1
0
44.1 kHz ± 4%
0
0
0
Channel Status
0
1
1
32 kHz ± 4%
0
1
1
Auxiliary Data
1
0
0
48 kHz ± 400 ppm
0
1
44.1 kHz ± 400 ppm
1
0
2
Independent Channel Status
1
1
1
3
Reserved
1
1
0
44.056 kHz ± 400 ppm
1
1
1
32 kHz ± 400 ppm
Table 1. Buffer Memory Modes
DS61PP4
Table 2. Incoming Sample Frequency Bits
11
CS8411
ROER, when set, causes the last audio sample to
be reread if the error pin, ERF, is active. When
out of lock, the CS8411 will output zeros if
ROER is set and output random data if ROER is
not set. The conditions that activate ERF are those
reported in SR2 and enabled in IER2. Figure 10
illustrates the modes selectable by SDF2-SDF0
and FSF1-FSF0. MSTR, which in most applications will be set to one, determines whether
FSYNC and SCK are outputs (MSTR = 1) or inFSF MSTR
10 (bit)
00
0 FSYNC Input
puts (MSTR = 0). When FSYNC and SCK are
inputs (slave mode) the audio data can be read
twice or missed if the device controlling FSYNC
and SCK is on a different time-base than the
CS8411. If the audio data is read twice or missed,
the SLIP bit in SR1 is set. SCED selects the SCK
edge to output data on. SCED high causes data to
be output on the falling edge, and SCED low
causes data to be output on the rising edge.
32 Bits
32 Bits
01
0
FSYNC Input
10
0
FSYNC Input
11
0
FSYNC Input
00
1
FSYNC Output
16 Clocks
16 Clocks
01
1
FSYNC Output
16 Clocks
16 Clocks
10
1
FSYNC Output
11
1
FSYNC Output
SDF
210 (bit)
000
MSB First - 32
001
MSB Last
32 Clocks
32 Clocks
32 Clocks
32 Clocks
Right Sample
24 Bits, Incl. Aux
Left Sample
24 Bits, Incl. Aux
Name
MSB
LSB
24 Bits, Incl. Aux
MSB
LSB
LSB
24 Bits, Incl. Aux
MSB
LSB
MSB
MSB
16 Bits
16 Bits
011
LSB Last - 16
LSB
101
LSB Last - 18
LSB
MSB
18 Bits
MSB
MSB
18 Bits
LSB
MSB
LSB
20 Bits
LSB Last - 20
111
SPECIAL MODES:
SDF
210 MSTR
Name
100
0 Async SCK
24 Bits, Incl. Aux
0
MSB First - 24
24 Bits, Incl. Aux
LSB
LSB MSB
MSB
0
MSB First - 16
MSB
LSB MSB
16 Bits
LSB MSB
LSB MSB
32 Bits
010*
1
NRZ Data
100*
1
Bi-Phase Data
AUX
LSB
Bi-Phase Mark Data
MSB
24 Bits, Incl. Aux
16 Bits
010
LSB
MSB
LSB
24 Bits, Incl. Aux
110
LSB
MSB
LSB
MSB
LSB
20 Bits
MSB
LSB
MSB
32 Bits
MSB VUCP
AUX
LSB
MSB VUCP
AUX
Bi-Phase Mark Data
* Error flags are not accurate in these modes
Figure 10. CS8411 Serial Port SDATA and FSYNC Timing
12
DS61PP4
CS8411
Audio Serial Port
The audio serial port outputs the audio data portion from the received data and consists of three
pins: SCK, SDATA, and FSYNC. SCK clocks the
data out on the SDATA line. The edge that SCK
uses to output data is programmable from CR2.
FSYNC delineates the audio samples and may indicate the particular channel, left or right.
Figure 10 illustrates the multitude of formats that
SDATA and FSYNC can take.
NORMAL MODES
SCK and FSYNC can be inputs (MSTR = 0) or
outputs (MSTR = 1), and are usually programmed as outputs. As outputs, SCK contains 32
periods for each sample and FSYNC has four formats. The first two output formats of FSYNC
(shown in Figure 10) delineate each word and the
identification of the particular channel must be
kept track of externally. This may be done using
the rising edge of FLAG2 to indicate the next
data word is left channel data. The last two output
formats of FSYNC also delineate each channel
with the polarity of FSYNC indicating the particular channel. The last format has FSYNC
change one SCK cycle before the frame containing the data and may be used to generate an I2S
compatible interface.
When SCK is programmed as an input, 32 SCK
cycles per sample must be provided. (There are
two formats in the Special Modes section where
SCK can have 16 or 24 clocks per sample.) The
four modes where FSYNC is an input are similar
to the FSYNC output modes. The first two require a transition of FSYNC to start the sample
frame, whereas the last two are identical to the
corresponding FSYNC output modes. If the circuit generating SCK and FSYNC is not locked to
the master clock of the CS8411, the serial port
will eventually be reread or a sample will be
missed. When this occurs, the SLIP bit in SR1
will be set.
DS61PP4
SDATA can take on five formats in the normal
serial port modes. The first format (see Figure 10), MSB First, has the MSB aligned with the
start of a sample frame. Twenty-four audio bits
are output including the auxiliary bits. This mode
is compatible with many DSPs. If the auxiliary
bits are used for something other than audio data,
they must be masked off. The second format,
MSB Last, outputs data LSB first with the MSB
aligned to the end of the sample frame. This format is conducive to serial arithmetic. Both of the
above formats output all audio bits from the received data. The last three formats are LSB Last
formats that output the most significant 16, 18,
and 20 bits respectively, with the LSB aligned to
the end of the sample frame. These formats are
used by many interpolation filters.
SPECIAL MODES
Five special modes are included for unique applications. In these modes, the master bit, MSTR,
must be defined as shown in Figure 10. In the
first mode, Asynchronous SCK, FSYNC (which
is an output in this mode) is aligned to the incoming SCK. This mode is useful when the SCK is
locked to an external event and cannot be derived
from MCK. Since SCK is asynchronous, the
number of SCK cycles per sample frame will
vary. The data output will be MSB first, 24 bits,
and aligned to the beginning of a sample frame.
The second and third special modes are unique in
that they contain 24 and 16 SCK cycles respectively per sample frame, whereas all normal
modes contain 32 SCK cycles. In these two
modes, the data is MSB first and fills the entire
frame. The fourth special mode outputs NRZ data
including the V, U, C, and P bits and the preamble
replaced with zeros. SCK is an output with
32 SCK cycles per sample frame. The fifth mode
outputs the biphase data recovered from the transmission line with 64 SCK cycles output per
sample frame, with data changing on the rising
edge.
13
CS8411
Normally, data recovered by the CS8411 is delayed by two frames in propagating through the
part, but in the fourth and fifth special modes, the
data is delayed only a few bit periods before being output. However, error codes, and the C, U
and V bits follow the normal a pathway with a
two frame delay (so that the error code would be
output with the offending data in the other
modes). As a result, in special modes four and
five, the error codes are nearly two frames behind
the data output on SDATA.
Buffer Memory
In all buffer modes, the status, mask, and control
registers are located at addresses 0-3, and the user
data is buffered at locations 4 through 7. The parallel port can access any location in the user data
buffer at any time; however, care should be taken
not to read a location when that location is being
updated internally. This internal writing is done
through a second port of the buffer and is done in
a cyclic manner. As data is received, the bits are
assembled in an internal 8-bit shift register which,
when full, is loaded into the buffer memory. The
first bit received is stored in D0 and, after D7 is
received, the byte is written into the proper buffer
memory location.
The user data is received one bit per sub-frame.
At the channel status block boundary, the internal
pointer for writing user data is initialized to 04H
(Hex). After receiving eight user bits, the byte is
written to the address indicated by the user
pointer which is then incremented to point to the
next address. After receiving all four bytes of user
data, 32 audio samples, the user pointer is set to
04H again and the cycle repeats. FLAG0, in SR1
can be used to monitor the user data buffer. When
the last byte of the user buffer, location 07H, is
written, FLAG0 is set low and when the second
byte, location 05H, is written, FLAG0 is set high.
If the corresponding bit in the interrupt enable
register (IER1, bit 0) is set, a transition of FLAG0
will generate a low pulse on the interrupt pin. The
level of FLAG0 indicates which two bytes the
14
part will write next, thereby indicating which two
bytes are free to be read.
FLAG1 is buffer mode dependent and is discussed in the individual buffer mode sections. A
transition of FLAG1 will generate an interrupt if
the appropriate interrupt enable bit is set.
FLAG2 is set high after channel status byte 23,
the last byte of the block, is written and set low
after channel status byte 3 is written to the buffer
memory. FLAG2 is unique in that only the rising
edge can cause an interrupt if the appropriate interrupt enable bit in IER1 is set.
Figure 11 illustrates the flag timing for an entire
channel status block which includes 24 bytes of
channel status data per channel and 384 audio
samples. The lower portion of Figure 11 expands
the first byte of channel status showing eight pairs
of data, with a pair defined as a frame. This is
further expanded showing the first sub-frame
(A0) to contain 32 bits defined as per the digital
audio standards. When receiving stereo, channel A is left and channel B is right.
For all three buffer modes, the three most significant bits in SR1, shown in Figure 6, can be used
to monitor the channel status data. In buffer
mode 2, bits 7 and 6 change definition and are described in that section. Channel status data, as
described in the standards, is independent for
each channel. Each channel contains its own
block of channel status data, and in most systems,
both channels will contain the same channel
status data. Buffer modes 0 and 1 operate on one
block of channel status with the particular block
selected by the CS2/CS1 bit in CR1. CSDIF, bit 7
in SR1, indicates when the channel status data for
each channel is not the same even though only
one channel is being buffered. CRCE, bit 6 in
SR1, indicates a CRC error occurred in the buffered channel. CCHG, bit 5 in SR1, is set when
any bit in the buffered channel status bytes 0 to 3,
change from one block to the next.
DS61PP4
CS8411
BUFFER MODE 0
The user data buffer previously described is identical for all modes. Buffer mode 0 allocates the
rest of the buffer to channel status data. This
mode stores an entire block of channel status in
24 memory locations from address 08H to 1FH.
Channel status (CS) data is different from user
data in that channel status data is independent for
each channel. A block of CS data is defined as
one bit per frame, not one bit per sub-frame;
therefore, there are two blocks of channel status.
The CS2/CS1 bit in CR1 selects which channel is
stored in the buffer. In a typical system sending
stereo data, the channel status data for each channel would be identical.
FLAG1 in status register 1, SR1, can be used to
monitor the channel status buffer. In mode 0,
FLAG1 is set low after channel status byte 23 (the
last byte) is written, and is set high when channel
status byte 15, location 17H is written. If the corresponding interrupt enable bit in IER1 is set, a
transition of FLAG1 will generate a pulse on the
interrupt pin. Figure 12 illustrates the memory
write sequence for buffer mode 0 along with flag
timing. The arrows on the flag timing indicate
when an interrupt will occur if the appropriate interrupt enable bit is set. FLAG0 can cause an
interrupt on either edge, which is only shown in
the expanded portion of the figure for clarity.
Block
(384 Audio Samples)
Flag 2
Flag 1
Mode 0
Flag 1
Modes 1 & 2
Flag 0
23 0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0
Channel Status Byte
1
(Expanded)
Frame
A0
B0
A1
B1
A2
B2
A7
B7
(Expanded)
Sub-frame
3 4
7 8
bit 0
Preamble
Aux Data
LSB
27 28 29 30 31
MSB V U C P
Audio Data
Validity
User Data
Channel Status Data
Parity Bit
Figure 11. CS8411 Status Register Flag Timing
DS61PP4
15
CS8411
Block
(384 Audio Samples)
FLAG2
FLAG1
FLAG0
0
C.S. Byte
C.S. Address
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 0
1F 08
0B 0C
08
1
(Expanded)
FLAG0
C.S. Addr.
1F
User Addr.
07
08
05
04
09
07
06
0A
05
04
06
(Addresses are in Hex)
0B
07
Figure 12. CS8411 Buffer Memory Write Sequence - MODE 0
Block
(384 Audio Samples)
FLAG2
FLAG1
FLAG0
0
C.S. Byte
1
2
08
C.S. Address
3
4
5
0B 0C
6
7 8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 0
0F 0C
0F 0C
0F 0C
0F 0C
1
0F 08
(Addresses are in Hex)
(Expanded)
FLAG1
FLAG0
C.S. Addr. 0F
08
09
0A
0B
User Addr.
07
04
05
06
07
04
05
06
07
Aux. Addr.
1F 10
13,14
17 18
1B,1C
1F 10
13,14
17 18
1B,1C
1F
Figure 13. CS8411 Buffer Memory Write Sequence - MODE 1
16
DS61PP4
CS8411
BUFFER MODE 1
determines whether the channel status pointer is
writing to the first four-byte section of the channel status buffer or the second four-byte section,
while FLAG1 indicates which two bytes of the
section are free to update.
In buffer mode 1, eight bytes are allocated for
channel status data and sixteen bytes for auxiliary
data as shown in Figure 5. The user data buffer is
the same for all modes. The channel status buffer,
locations 08H to 0FH, is divided into two sections. The first four locations always contain the
first four bytes of channel status, identical to
mode 0, and are written once per channel status
block. The second four locations, addresses 0CH
to 0FH, provide a cyclic buffer for the last
20 bytes of channel status data. The channel
status buffer is divided in this fashion because the
first four bytes are the most important ones;
whereas, the last 20 bytes are often not used (except for byte 23, CRC).
The auxiliary data buffer, locations 10H to 1FH,
is written to in a cyclic manner similar to the
other buffers. Four auxiliary data bits are received
per audio sample (sub-frame) and, since the auxiliary data is four times larger than the user data,
the auxiliary data buffer on the CS8411 is four
times larger allowing FLAG0 to be used to monitor both.
BUFFER MODE 2
In buffer mode 2, two 8-byte buffers are available
to independently buffer each channel of channel
status data. Both buffers are identical to the channel status buffer in mode 1 and are written to
simultaneously, with locations 08H to 0FH containing CS data for channel A and locations 10H
to 17H containing CS data for channel B. Both
FLAG1 and FLAG2 can be used to monitor this
buffer as shown in Figure 13. FLAG1 is set high
when CS byte 1, location 09H, is written and is
toggled when every other byte is written. FLAG2
is set high after CS byte 23 is written and set low
after CS byte 3, location 0BH, is written. FLAG2
Block
(384 Audio Samples)
FLAG2
FLAG1
FLAG0
C.S. Byte
Left C.S. Ad.
0
08
Right C.S. Ad.
10
1
2
3 4
0B 0C
5
13 14
6
7 8
0F 0C
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 0
0F 0C
0F 0C
0F 0C
0F 08
17 14
17 14
(Expanded)
17 14
17 14
1
14 10
(Addresses are in Hex)
FLAG1
FLAG0
Left C.S. Ad.
Right C.S. Ad.
User Address
04
08
10
05
06
09
11
07
04
0A
12
05
06
0B
13
07
Figure 14. CS8411 Buffer Memory Write Sequence - MODE 2
DS61PP4
17
CS8411
CS buffers can be monitored using FLAG1 and
FLAG2 as described in the BUFFER MODE 1
section.
The two most significant bits in SR1 change definition for buffer mode 2. These two bits, when
set, indicate CRC errors for their respective channels. A CRC error occurs when the internal
calculated CRC for channel status bytes 0
through 22 does not match channel status byte 23.
CCHG, bit 5 in SR1, is set when any bit in the
first four channel status bytes of either channel
changes from one block to the next. Since channel status doesn’t change very often, this bit may
be monitored rather than checking all the bits in
the first four bytes. These bits are illustrated in
Figure 6.
Buffer Updates and Interrupt Timing
As mentioned previously in the buffer mode sections, conflicts between externally reading the
buffer RAM and the CS8411 internally writing to
it may be averted by using the flag levels to avoid
the section currently being addressed by the part.
However, if the interrupt line, along with the
flags, is utilized, the actual byte that was just updated can be determined. In this way, the entire
buffer can be read without concern for internal
updates. Figure 15 shows the detailed timing for
the interrupt line, flags, and the RAM write line.
SCK is 64 times the incoming sample frequency,
and is the same SCK output in master mode. The
FSYNC shown is valid for all master modes except the I2S compatible mode. The interrupt pulse
is shown to be 4 SCK periods wide and goes low
5 SCK periods after the RAM is written. Using
the above information, the entire data buffer may
be read starting with the next byte to be updated
by the internal pointer.
ERF Pin Timing
ERF signals that an error occurred while receiving the audio sample that is currently being read
from the serial port. ERF changes with the active
edge of FSYNC and is high during the errorred
sample. ERF is affected by the error conditions
reported in SR2: CONF, LOCK, CODE, PARITY,
and V. Any of these conditions may be masked off
using the corresponding bits in IER2. The ERF
pin will go high for each error that occurs. The
ERF bit in SR1 is different from the ERF pin in
that it only causes an interrupt the first time an
error occurs until SR1 is read. More information
on the ERF pin and bit is contained at the end of
the Status and IEnable Registers section.
SCK
FSYNC
Left 191
Right 191
Left 0
IWRITE
___
INT
(FLAG0,1)
___
INT
(FLAG2)
FSF1,0 = 1 0
MSTR = 1
SCED = 1
Figure 15. RAM/Buffer-Write and Interrupt Timing
18
DS61PP4
CS8411
PIN DESCRIPTIONS:
CS8411
DATA BUS BIT 2
DATA BUS BIT 3
DATA BUS BIT 4
DATA BUS BIT 5
DATA BUS BIT 6
DATA BUS BIT 7
DIGITAL POWER
DIGITAL GROUND
RECEIVE POSITIVE
RECEIVE NEGATIVE
FRAME SYNC
SERIAL DATA CLOCK
ADD BUS BIT 4 / FCLOCK
INTERRUPT
D2
D3
D4
D5
D6
D7
VD+
DGND
RXP
RXN
FSYNC
SCK
A4/FCK
INT
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
D1
D0
SDATA
ERF
CS
RD/WR
VA+
AGND
FILT
MCK
A0
A1
A2
A3
DATA BUS BIT 1
DATA BUS BIT 0
SERIAL OUTPUT DATA
ERROR FLAG
CHIP SELECT
READ/WRITE SELECT
ANALOG POWER
ANALOG GROUND
FILTER
MASTER CLOCK
ADDRESS BUS BIT 0
ADDRESS BUS BIT 1
ADDRESS BUS BIT 2
ADDRESS BUS BIT 3
Power Supply Connections
VD+ - Positive Digital Power, PIN 7.
Positive supply for the digital section. Nominally +5 volts.
VA+ - Positive Analog Power, PIN 22.
Positive supply for the analog section. Nominally +5 volts. This supply should be as
quiet as possible since noise on this pin will directly affect the jitter performance of the
recovered clock.
DGND - Digital Ground, PIN 8.
Ground for the digital section. DGND should be connected to same ground as AGND.
AGND - Analog Ground, PIN 21.
Ground for the analog section. AGND should be connected to same ground as DGND.
Audio Output Interface
SCK - Serial Clock, PIN 12.
Serial clock for SDATA pin which can be configured (via control register 2) as an input
or output, and can sample data on the rising or falling edge. As an input, SCK must
contain 32 clocks for every audio sample in all normal audio serial port formats.
DS61PP4
19
CS8411
FSYNC - Frame Sync, PIN 11.
Delineates the serial data and may indicate the particular channel, left or right. Also,
FSYNC may be configured as an input or output. The format is based on bits in control
register 2.
SDATA - Serial Data, PIN 26.
Audio data serial output pin.
ERF - Error Flag, PIN 25.
Signals that an error has occurred while receiving the audio sample currently being read
from the serial port. The errors that cause ERF to go high are enumerated in status
register 2 and enabled by setting the corresponding bit in IEnable register 2.
A4/FCK - Address Bus Bit 4/Frequency Clock, PIN 13.
This pin has a dual function and is controlled by the FCEN bit in control register 1. A4
is the address bus pin as defined below. When used as FCK, an internal frequency
comparator compares a 6.144 MHz clock input on this pin to the received clock
frequency and stores the value in status register 1 as three FREQ bits. These bits
indicate the incoming frequency as well as the tolerance. When defined as FCK, A4 is
internally set to 0.
Parallel Interface
CS - Chip Select, PIN 24.
This input is active low and allows access to the 32 bytes of internal memory. The
address bus and RD/WR must be valid while CS is low.
RD/WR - Read/Write, PIN 23.
If RD/WR is low when CS goes active (low), the data on the data bus is written to
internal memory. If RD/WR is high when CS goes active, the data in the internal
memory is placed on the data bus.
A4-A0 - Address Bus, PINS 13, 15-18.
Parallel port address bus that selects the internal memory location to be read from or
written to. Note that A4 is the dual function pin A4/FCK as described above.
D0-D7 - Data Bus, PINS 27-28, 1-6.
Parallel port data bus used to check status, read or write control words, or read internal
buffer memory.
20
DS61PP4
CS8411
INT - Interrupt, PIN 14.
Open drain output that can signal the state of the internal buffer memory as well as error
information. A 5kΩ resistor to VD+ is typically used to support logic gates. All bits
affecting INT are maskable to allow total control over the interrupt mechanism.
Receiver Interface
RXP, RXN - Differential Line Receivers, PINS 9, 10.
RS422 compatible line receivers. Described in detail in Appendix A.
Phase Locked Loop
MCK - Master Clock, PIN 19.
Low jitter clock output of 256 times the received sample frequency.
FILT - Filter, PIN 20.
An external 1kΩ resistor and 0.047µF capacitor are required from the FILT pin to
analog ground.
DS61PP4
21
CS8412
CS8412 DESCRIPTION
The line receiver and jitter performance are described in the sections directly preceding the
CS8411 sections in the beginning of this data
sheet.
The CS8412 does not need a microprocessor to
handle the non-audio data (although a micro may
be used with the C and U serial ports). Instead,
dedicated pins are available for the most important channel status bits. The CS8412 is a
monolithic CMOS circuit that receives and decodes digital audio data which was encoded
according to the digital audio interface standards.
It contains an RS422 line receiver and clock and
data recovery utilizing an on-chip phase-locked
loop. The audio data is output through a configurable serial port that supports 14 formats. The
channel status and user data have their own serial
pins and the validity flag is OR’ed with the ERF
flag to provide a single pin, VERF, indicating that
the audio output may not be valid. This pin may
be used by interpolation filters that provide error
correction. A block diagram of the CS8412 is illustrated in Figure 16.
VA+
22
RXP
9
FILT
AGND
20
21
Audio Serial Port
The audio serial port is used primarily to output
audio data and consists of three pins: SCK,
FSYNC, and SDATA. These pins are configured
via four control pins: M0, M1, M2, and M3. M3
selects between eight normal serial formats (M3 =
0), and six special formats (M3 = 1).
NORMAL MODES (M3 = 0)
When M3 is low, the normal serial port formats
shown in Figure 17 are selected using M2, M1,
and M0. These formats are also listed in Table 3,
wherein the first word past the format number
(Out-In) indicates whether FSYNC and SCK are
M3
MCK
19
17
M1
18
24
M0
23
Timing
Clock & Data
Recovery
RXN
M2
11
10
Confidence
Flag
VD+
DGND
CS12/
FCK
De-Multiplexer
12
26
1
7
8
CRC
check
Parity
Check
13
Channel
Status
Latch
Error
Encoder
Frequency
Comparator
SEL
Audio
Serial
Port
Bi-phase
Decoder
and
Frame
Sync
16
R
e
g
i
s
t
e
r
s
14
28
FSYNC
SCK
SDATA
C
U
VERF
15
CBL
25
ERF
Multiplexer
6
5
C0/
E0
Ca/
E1
4
3
Cb/
E2
2
Cc/
F0
27
Cd/
F1
Ce/
F2
Figure 16. CS8412 Block Diagram
22
DS61PP4
CS8412
outputs from the CS8412 or are inputs. The next
word (L/R-WSYNC) indicates whether FSYNC
indicates the particular channel or just delineates
each word. If an error occurs (ERF = 1) while
using one of these formats, the previous valid
audio data for that channel will be output. As long
as ERF is high, that same data word will be output. If the CS8412 is not locked, it will output all
zeroes. In some modes FSYNC and SCK are outputs and in others they are inputs. In Table 3,
LSBJ is short for LSB justified where the LSB is
justified to the end of the audio frame and the
MSB varies with word length. As outputs the
CS8412 generates 32 SCK periods per audio
sample (64 per stereo sample) and, as inputs, 32
SCK periods must be provided per audio sample.
When FSYNC and SCK are inputs, one stereo
sample is double buffered. For those modes
which output 24 bits of audio data, the auxiliary
bits will be included. If the auxiliary bits are not
used for audio data, they must be masked off.
SPECIAL MODES (M3 = 1)
When M3 is high, the special audio modes described in Table 4 are selected via M2, M1, and
M0. In formats 8, 9, and 10, SCK, FSYNC, and
SDATA are the same as in formats 0, 1, and 2 respectively; however, the recovered data is output
as is even if ERF is high, indicating an error. (In
modes 0-2 the previous valid sample is output.)
Similarly, when out of lock, the CS8412 will still
output all the recovered data, which should be zeros if there is no input to the RXP, RXN pins.
Format
Format 11 is similar to format 0 except that SCK
is an input and FSYNC is an output. In this mode
FSYNC and SDATA are synchronized to the incoming SCK, and the number of SCK periods
between FSYNC edges will vary since SCK is
not synchronous to received data stream. This
mode may be useful when writing data to storage.
Format 12 is similar to format 7 except that
SDATA is the entire data word received from the
transmission line including the C, U, V, and P
bits, with zeros in place of the preamble. In format 13 SDATA contains the entire biphase
encoded data from the transmission line including
the preamble, and SCK is twice the normal frequency. The normal two frame delay of data from
input to output is reduced to only a few bit periods in formats 12 and 13. However, the C, U, V
bits and error codes follow their normal pathways
and therefore follow the output data by nearly
two frames. Figure 18 illustrates formats 12 and
13. Format 14 is reserved and not presently used,
and format 15 causes the CS8412 to go into a reset state. While in reset all outputs will be inactive
except MCK. The CS8412 comes out of reset at
the first block boundary after leaving the reset
state.
C, U, VERF, ERF, and CBL Serial Outputs
The C and U bits and CBL are output one SCK
period prior to the active edge of FSYNC in all
serial port formats except 2 and 3 (I2S modes).
The active edge of FSYNC may be used to latch
C, U, and CBL externally. In formats 2 and 3,
M2
M1
M0
M2
M1
M0
0
0
0
0 - Out, L/R, 16-24 Bits
0
0
0
8 - Format 0 - No repeat on error
0
0
1
1 - In, L/R, 16-24 Bits
0
0
1
9 - Format 1 - No repeat on error
0
1
0
2 - Out, L/R, I2S Compatible
0
1
0
10 - Format 2 - No repeat on error
0
1
1
3 - In, L/R, I2S Compatible
0
1
1
11 - Format 0 - Async. SCK input
1
0
0
4 - Out, WSYNC, 16-24 Bits
1
0
0
12 - Received NRZ Data
1
0
1
5 - Out, L/R, 16 Bits LSBJ
1
0
1
13 - Received Bi-phase Data
1
1
0
6 - Out, L/R, 18 Bits LSBJ
1
1
0
14 - Reserved
1
1
1
7 - Out, L/R, MSB Last
1
1
1
15 - CS8412 Reset
Table 3. Normal Audio Port Modes (M3=0)
DS61PP4
Format
Table 4. Special Audio Port Modes (M3=1)
23
CS8412
FMT
No. M2 M1 M0
FSYNC (out)
0
0
0
0
SCK (out)
0
0
1
LSB
MSB
SDATA (out)
1
Right
Left
FSYNC (in)
MSB
LSB
MSB
LSB
MSB
Right
Left
SCK (in)
MSB
SDATA (out)
Left
FSYNC (out)
2
0
1
0
1
1
1
0
0
MSB
Left
MSB
LSB
Right
SCK (in)
SDATA (out)
4
LSB
MSB
FSYNC (in)
0
Right
SCK (out)
SDATA (out)
3
MSB
LSB
MSB
FSYNC (out)
MSB
LSB
MSB
LSB
Right
Left
SCK (out)
SDATA (out)
MSB
FSYNC (out)
5
1
0
1
LSB
MSB
LSB
Right
Left
SCK (out)
SDATA (out)
LSB
MSB
LSB
MSB
FSYNC (out)
1
1
Right
Left
0
LSB
16 Bits
16 Bits
6
MSB
SCK (out)
SDATA (out)
LSB
LSB
MSB
18 Bits
18 Bits
FSYNC (out)
7
1
1
1
LSB
MSB
Right
Left
SCK (out)
SDATA (out)
MSB
LSB
MSB
LSB
MSB
Figure 17. CS8412 Audio Serial Port Formats
24
DS61PP4
CS8412
No.
12
FSYNC (out)
Right
Left
SCK (out)
SDATA (out)
13
AUX
FSYNC (out)
MSB V U C P
LSB
AUX
MSB V U C P
LSB
Right
Left
SCK (out)
SDATA (out)
AUX
MSB V U C P
LSB
AUX
LSB
MSB V U C P
Figure 18. Special Audio Port Formats 12 and 13
the C and U bits and CBL are updated with the
active edge of FSYNC. The validity + error flag
(VERF) and the error flag (ERF) are always updated at the active edge of FSYNC. This timing is
illustrated in Figure 19.
The C output contains the channel status bits with
CBL rising indicating the start of a new channel
status block. CBL is high for the first four bytes
of channel status (32 frames or 64 samples) and
low for the last 20 bytes of channel status
(160 frames or 320 samples). The U output contains the User Channel data. The V bit is OR’ed
with the ERF flag and output on the VERF pin.
This indicates that the audio sample may be in
error and can be used by interpolation filters to
interpolate through the error. ERF being high in-
dicates a serious error occurred on the transmission line. There are three errors that cause ERF to
go high: a parity error or biphase coding violation
during that sample, or an out of lock PLL receiver. Timing for the above pins is illustrated in
Figure 19.
Multifunction Pins
There are seven multifunction pins which contain
either error and received frequency information,
or channel status information, selectable by SEL.
ERROR AND FREQUENCY REPORTING
When SEL is low, error and received frequency
information are selected. The error information is
encoded on pins E2, E1, and E0, and is decoded
CBL
C0,
Ca-Ce
SDATA Right 191
Left 0
Right 0
Left 1
Right 31
Left 32
Right 191
Left 0
FSYNC
ERF,
VERF
C, U
Figure 19. CBL Timing
DS61PP4
25
CS8412
as shown in Table 5. When an error occurs, the
corresponding error code is latched. Clearing is
then accomplished by bringing SEL high for
more than eight MCK cycles. The errors have a
priority associated with their error code, with validity having the lowest priority and no lock
having the highest priority. Since only one code
can be displayed, the error with the highest priority that occurred since the last clearing will be
selected.
The validity flag indicates that the validity bit for
a previous sample was high since the last clearing
of the error codes. The confidence flag occurs
when the received data eye opening is less than
half a bit period. This indicates that the quality of
the transmission link is poor and does not meet
the digital audio interface standards. The slipped
sample error can only occur when FSYNC and
SCK of the audio serial port are inputs. In this
case, if FSYNC is asynchronous to the received
data rate, periodically a stereo sample will be
dropped or reread depending on whether the read
rate is slower or faster than the received data rate.
When this occurs, the slipped sample error code
will appear on the ’E’ pins. The CRC error is updated at the beginning of a channel status block,
and is only valid when the professional format of
channel status data is received. This error is indicated when the CS8412 calculated CRC value
does not match the CRC byte of the channel
status block or when a block boundary changes
(as in removing samples while editing). The parE2
E1
E0
0
0
0
0
0
The received frequency information is encoded
on pins F2, F1, and F0, and is decoded as shown
in Table 6. The on-chip frequency comparator
compares the received clock frequency to an externally supplied 6.144 MHz clock which is input
on the FCK pin. The ’F’ pins are updated three
times during a channel status block including
prior to the rising edge of CBL. CBL may be
used to externally latch the ’F’ pins. The clock on
FCK must be valid for two thirds of a block for
the ’F’ pins to be accurate.
CHANNEL STATUS REPORTING
When SEL is high, channel status is displayed on
C0, and Ca-Ce for the channel selected by CS12.
If CS12 is low, channel status for sub-frame 1 is
displayed, and if CS12 is high, channel status for
sub-frame 2 is displayed. The contents of Ca-Ce
depend upon the C0 professional/consumer bit.
The information reported is shown in Table 7.
Error
F2
F1
F0
Sample Frequency
0
No Error
0
0
0
Out of Range
1
Validity Bit High
0
0
1
48kHz ± 4%
1
0
Confidence Flag
0
1
0
44.1kHz ± 4%
0
1
1
Slipped Sample
0
1
1
32kHz ± 4%
1
0
0
CRC Error (PRO only)
1
0
0
48kHz ± 400 ppm
1
0
1
Parity Error
1
0
1
44.1kHz ± 400 ppm
1
1
0
Bi-Phase Coding Error
1
1
0
44.056kHz ± 400 ppm
1
1
1
No Lock
1
1
1
32kHz ± 400 ppm
Table 5. Error Decoding
26
ity error occurs when the incoming sub-frame
does not have even parity as specified by the
standards. The biphase coding error indicates a
biphase coding violation occurred. The no lock
error indicates that the PLL is not locked onto the
incoming data stream. Lock is achieved after receiving three frame preambles then one block
preamble, and is lost after not receiving four consecutive frame preambles.
Table 6. Sample Frequency Decoding
DS61PP4
CS8412
Professional Channel Status (C0 = 0)
When C0 is low, the received channel status block
is encoded according to the professional/broadcast format. The Ca through Ce pins are defined
for some of the more important professional bits.
As listed in Table 7, Ca is the inverse of channel
status bit 1. Therefore, if the incoming channel
status bit 1 is 1, Ca, defined as C1, will be 0. C1
indicates whether audio (C1 = 1) or non-audio
(C1 = 0) data is being received. Cb and Cc, defined as EM0 and EM1 respectively, indicate
emphasis and are encoded versions of channel
status bits 2, 3, and 4. The decoding is listed in
Table 8. Cd, defined as C9, is the inverse of channel status bit 9, which gives some indication of
channel mode. (Bit 9 is also defined as bit 1 of
byte 1.) When Ce, defined as CRCE, is low, the
CS8412 calculated CRC value does not match the
received CRC value. This signal may be used to
qualify Ca through Cd. If Ca through Ce are being displayed, Ce going low can indicate not to
update the display.
Consumer Channel Status (C0 = 1)
When C0 is high, the received channel status
block is encoded according to the consumer format. In this case Ca through Ce are defined
differently as shown in Table 7. Ca is the inverse
of channel status bit 1, C1, indicating audio (C1 =
1) or non-audio (C1 = 0). Cb is defined as the
inverse of channel status bit 2, C2, which indicates copy inhibit/copyright information. Cc,
defined as C3, is the emphasis bit of channel
status, with C3 low indicating the data has had
pre-emphasis added.
The audio standards, in consumer mode, describe
bit 15, L, as the generation status which indicates
whether the audio data is an original work or a
copy (1st generation or higher). The definition of
the L bit is reversed for three category codes: two
broadcast codes, and laser-optical (CD’s). Therefore, to interpret the L bit properly, the category
code must be decoded. The CS8412 does this decoding internally and provides the ORIG signal
that, when low, indicates that the audio data is
original over all category codes.
SCMS
The consumer audio standards also mention a serial copy management system, SCMS, for dealing
with copy protection of copyrighted works.
SCMS is designed to allow unlimited duplication
of the original work, but no duplication of any
copies of the original. This system utilizes the
channel status bit 2, Copy, and channel status
bit 15, L or generation status, along with the category codes. If the Copy bit is 0, copyright
protection is asserted over the material. Then, the
L bit is used to determine if the material is an
original or a duplication. (As mentioned in the
previous paragraph, the definition of the L bit can
be reversed based on the category codes.) There
are two category codes that get special attention:
general and A/D converters without C or L bit information. For these two categories the SCMS
standard requires that equipment interfacing to
these categories set the C bit to 0 (copyright protection asserted) and the L bit to 1 (original). To
support this feature, Ce, in the consumer mode, is
defined as IGCAT (ignorant category) which is
low for the "general" (0000000) and "A/D converter without copyright information" (01100xx)
categories.
Pin
Professional
Consumer
C0
0 (low)
1 (high)
Ca
C1
C1
EM1
EM0
C2
C3
C4
Cb
EM0
C2
0
0
1
1
1
Cc
EM1
C3
0
1
1
1
0
Cd
C9
ORIG
1
0
1
0
0
Ce
CRCE
IGCAT
1
1
0
0
0
Table 7. Channel Status Pins
DS61PP4
Table 8. Emphasis Encoding
27
CS8412
PIN DESCRIPTIONS:
CS8412
CHANNEL STATUS OUTPUT
C
CS d / FREQ REPORT 1
Cd/F1
CS c / FREQ REPORT 0
Cc/F0
CS b / ERROR CONDITION 2
Cb/E2
CS a / ERROR CONDITION 1
Ca/E1
CS 0 / ERROR CONDITION 0
C0/E0
DIGITAL POWER
VD+
DIGITAL GROUND
DGND
RECEIVE POSITIVE
RXP
RECEIVE NEGATIVE
RXN
FRAME SYNC
FSYNC
SERIAL DATA CLOCK
SCK
CHANNEL SELECT / FCLOCK CS12/FCK
USER DATA OUTPUT
U
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
VERF
Ce/F2
SDATA
ERF
M1
M0
VA+
AGND
FILT
MCK
M2
M3
SEL
CBL
VALIDITY + ERROR FLAG
CS e / FREQ REPORT 2
SERIAL OUTPUT DATA
ERROR FLAG
SERIAL PORT MODE SELECT
SERIAL PORT MODE SELECT
ANALOG POWER
ANALOG GROUND
FILTER
MASTER CLOCK
SERIAL PORT MODE SELECT
SERIAL PORT MODE SELECT
FREQ/CS SELECT
CS BLOCK START
1
2
2
3
Power Supply Connections
VD+ - Positive Digital Power, PIN 7.
Positive supply for the digital section. Nominally +5 volts.
VA+ - Positive Analog Power, PIN 22.
Positive supply for the analog section. Nominally +5 volts.
DGND - Digital Ground, PIN 8.
Ground for the digital section. DGND should be connected to same ground as AGND.
AGND - Analog Ground, PIN 21.
Ground for the analog section. AGND should be connected to same ground as DGND.
Audio Output Interface
SCK - Serial Clock, PIN 12.
Serial clock for SDATA pin which can be configured (via the M0, M1, M2, and M3
pins) as an input or output, and can sample data on the rising or falling edge. As an
output, SCK will generate 32 clocks for every audio sample. As an input, 32 SCK
periods per audio sample must be provided in all normal modes.
FSYNC - Frame Sync, PIN 11.
Delineates the serial data and may indicate the particular channel, left or right, and may
be an input or output. The format is based on M0, M1, M2, and M3 pins.
28
DS61PP4
CS8412
SDATA - Serial Data, PIN 26.
Audio data serial output pin.
M0, M1, M2, M3 - Serial Port Mode Select, PINS 23, 24, 18, 17.
Selects the format of FSYNC and the sample edge of SCK with respect to SDATA. M3
selects between eight normal modes (M3 = 0), and six special modes (M3 = 1).
Control Pins
VERF - Validity + Error Flag, PIN 28.
A logical OR’ing of the validity bit from the received data and the error flag. May be
used by interpolation filters to interpolate through errors.
U - User Bit, PIN 14.
Received user bit serial output port. FSYNC may be used to latch this bit externally.
C - Channel Status Output, PIN 1.
Received channel status bit serial output port. FSYNC may be used to latch this bit
externally.
CBL - Channel Status Block Start, PIN 15.
The channel status block output is high for the first four bytes of channel status and low
for the last 16 bytes.
SEL - Select, PIN 16.
Control pin that selects either channel status information (SEL = 1) or error and
frequency information (SEL = 0) to be displayed on six of the following pins.
C0, Ca, Cb, Cc, Cd, Ce - Channel Status Output Bits, PINS 2-6, 27.
These pins are dual function with the ’C’ bits selected when SEL is high. Channel status
information is displayed for the channel selected by CS12. C0, which is channel status
bit 0, defines professional (C0 = 0) or consumer (C0 = 1) mode and further controls the
definition of the Ca-Ce pins. These pins are updated with the rising edge of CBL.
CS12 - Channel Select, PIN 13.
This pin is also dual function and is selected by bringing SEL high. CS12 selects
sub-frame 1 (when low) or sub-frame 2 (when high) to be displayed by channel status
pins C0 and Ca through Ce.
FCK - Frequency Clock, PIN 13.
Frequency Clock input that is enabled by bringing SEL low. FCK is compared to the
received clock frequency with the value displayed on F2 through F0. Nominal input
value is 6.144 MHz.
DS61PP4
29
CS8412
E0, E1, E2 - Error Condition, PINS 4-6.
Encoded error information that is enabled by bringing SEL low. The error codes are
prioritized and latched so that the error code displayed is the highest level of error since
the last clearing of the error pins. Clearing is accomplished by bring SEL high for more
than 8 MCK cycles.
F0, F1, F2 - Frequency Reporting Bits, PINS 2-3, 27.
Encoded sample frequency information that is enabled by bringing SEL low. A proper
clock on FCK must be input for at least two thirds of a channel status block for these
pins to be valid. They are updated three times per block, starting at the block boundary.
ERF - Error Flag, PIN 25.
Signals that an error has occurred while receiving the audio sample currently being read
from the serial port. Three errors cause ERF to go high: a parity or biphase coding
violation during the current sample, or an out of lock PLL receiver.
Receiver Interface
RXP, RXN - Differential Line Receivers, PINS 9, 10.
RS422 compatible line receivers.
Phase Locked Loop
MCK - Master Clock, PIN 19.
Low jitter clock output of 256 times the received sample frequency.
FILT - Filter, PIN 20.
An external 1kΩ resistor and 0.047µF capacitor is required from FILT pin to analog
ground.
30
DS61PP4
CS8411 CS8412
APPENDIX A: RS422 Receiver Information
The RS422 receivers on the CS8411 and
CS8412 are designed to receive both the professional and consumer interfaces, and meet all
specifications listed in the digital audio standards. Figure A1 illustrates the internal schematic
of the receiver portion of both chips. The receiver has a differential input. A Schmitt trigger
is incorporated to add hysteresis which prevents
noisy signals from corrupting the phase detector.
flowing down the shield of the cable that could
result when boxes with different ground potentials are connected. Generally, it is good practice
to ground the shield to the chassis of the transmitting unit, and connect the shield through a
capacitor to chassis ground at the receiver. However, in some cases it is advantagous to have the
ground of two boxes held to the same potential,
and the cable shield might be depended upon to
make that electrical connection. Generally, it
8k
Professional Interface
The digital audio specifications for professional
use call for a balanced receiver, using XLR connectors, with 110Ω ± 20% impedance. (The
XLR connector on the receiver should have female pins with a male shell.) Since the receiver
has a very high impedance, a 110Ω resistor
should be placed across the receiver terminals to
match the line impedance, as shown in Figure A2, and, since the part has internal biasing,
no external biasing network is needed. If some
isolation is desired without the use of transformers, a 0.01µF capacitor should be placed on the
input of each pin (RXP and RXN) as shown in
Figure A3. However, if transformers are not
used, high frequency energy could be coupled
between transmitter and receiver causing degradation in analog performance.
Although transformers are not required by AES
they are strongly recommended. The EBU requires transformers. Figures A2 and A3 show an
optional DC blocking capacitor on the transmission line. A 0.1 to 0.47µF ceramic capacitor may
be used to block any DC voltage that is accidentally connected to the digital audio receiver. The
use of this capacitor is an issue of robustness as
the digital audio transmission line does not have
a DC voltage component.
Grounding the shield of the cable is a tricky issue. In the configuration of systems, it is
important to avoid ground loops and DC current
DS61PP4
9
RXP
8k
16 k
+
10
RXN
16 k
_
4k
4k
Figure A1. RS422 Receiver Internal Circuit
XLR
CS8411/12
* See Text
RXP
110
Twisted
Pair
110
RXN
1
Figure A2. Professional Input Circuit
XLR
* See Text 0.01 uF
CS8411/12
RXP
110
Twisted
Pair
110
0.01 uF
RXN
1
Figure A3. Transformerless Professional Circuit
RCA Phono
75
Coax
CS8411/12
0.01 uF
RXP
75
0.01
uF
RXN
Figure A4. Consumer Input Circuit
31
CS8411 CS8412
may be a good idea to provide the option of
grounding or capacitively coupling to ground
with a "ground-lift" circuit.
Consumer Interface
In the case of the consumer interface, the standards call for an unbalanced circuit having a
receiver impedance of 75Ω ±5%. The connector
for the consumer interface is an RCA phono
plug (fixed socket described in Table IV of
IEC 268-11). The receiver circuit for the consumer interface is shown in Figure A4.
TTL/CMOS Levels
The following are a few typical transformers:
The circuit shown in Figure A5 may be used
when external RS422 receivers or TTL/CMOS
logic drive the CS8411/12 receiver section.
Pulse Engineering
Telecom Products Group
7250 Convoy Ct.
San Diego, CA 92111
(619) 268-2400
Part Number: PE65612
TTL/CMOS
Gate
0.01 uF
CS8411/12
RXP
0.01
uF
RXN
Figure A5. TTL/CMOS Interface
Transformers
The transformer used in the professional interface should be capable of operation from 1.5 to
7 MHz, which is the audio data rate of 25 kHz
to 55 kHz after biphase-mark encoding. Transformers provide isolation from ground loop,
60 Hz noise, and common mode noise and interference. One of the important considerations
when choosing transformers is minimizing shunt
capacitance between primary and secondary
windings. The higher the shunt capacitance, the
lower the isolation between primary and secondary and the more coupling that can occur for
high frequency energy. This energy appears in
the form of common mode noise on the receive
side ground and has the potential to degrade analo g p erfo rmance. Th erefore, shielded
transformers optimized for minimum primary to
secondary capacitance may be desirable.
32
Schott Corporation
1000 Parkers Lane Rd.
Wayzata, MN 55391
(615) 889-8800
Part Number: 67125450
67128990 - lower cost
67129000 - surface mount
67129600 - single shield
Scientific Conversions Inc.
42 Truman Dr.
Novato, CA 94947
(415) 892-2323
Part Number: SC916-01 - single shield
SC916-01A - improved version
SC937-01 - low profile
SC937-02 - surface mount
DS61PP4
CS8411 CS8412
ORDERING GUIDE
Model
Temperature Range
Package
CS8411-CP
CS8411-IP
CS8411-CS
CS8411-IS
0 to 70 °C*
-40 to 85 °C
0 to 70 °C*
-40 to 85 °C
28-Pin Plastic .6" DIP
28-Pin Plastic .6" DIP
28-Pin Plastic SOIC
28-Pin Plastic SOIC
CS8412-CP
CS8412-IP
CS8412-CS
CS8412-IS
0 to 70 °C*
-40 to 85 °C
0 to 70 °C*
-40 to 85 °C
28-Pin Plastic .6" DIP
28-Pin Plastic .6" DIP
28-Pin Plastic SOIC
28-Pin Plastic SOIC
* Although the ’-CP’ and ’-CS’ suffixed parts are guaranteed to operate over 0 to 70 °C, they are tested
at 25 °C only. If testing over temperature is desired, the ’-IP’ and ’-IS’ suffixed parts are
tested over their specified temperature range.
DS61PP4
33
15
28
28 pin
Plastic DIP
E1
1
14
D
A
SEATING
PLANE
A1
B1
e1
B
L
∝
C
eA
NOTES:
1. POSITIONAL TOLERANCE OF LEADS SHALL BE WITHIN
0.25mm (0.010") AT MAXIMUM MATERIAL CONDITION, IN
RELATION TO SEATING PLANE AND EACH OTHER.
2. DIMENSION eA TO CENTER OF LEADS WHEN FORMED PARALLEL.
3. DIMENSION E1 DOES NOT INCLUDE MOLD FLASH.
MILLIMETERS
INCHES
DIM MIN NOM MAX MIN NOM MAX
3.94 4.32 5.08 0.155 0.170 0.200
A
A1 0.51 0.76 1.02 0.020 0.030 0.040
B
0.36 0.46 0.56 0.014 0.018 0.022
B1 1.02 1.27 1.65 0.040 0.050 0.065
C
0.20 0.25 0.38 0.008 0.010 0.015
36.45 36.83 37.21 1.435 1.450 1.465
D
E1 13.72 13.97 14.22 0.540 0.550 0.560
e1 2.41 2.54 2.67 0.095 0.100 0.105
eA 15.24
15.87 0.600
0.625
L
3.18
0.150
3.81 0.125
0°
15°
15°
0°
∝
pins
16
20
24
D
28
AAA
AA AAA
AA
AAA
AAA AA
AA AAA
AAA AA
AA
AA AAA
AA
AA AAA
AAA
DIM
SOIC
A
A1
A2
E1 E
AA
AAA
AA AAA
AAA
AAA AA
AA AAA
AAA AA
AA
AA
AAA
AA
AA AAA
AAA
b
c
A2
AAA
e
AA
AAA AA
AAA
b
AA
A1
D
E
E1
A
µ
c
L
e
L
µ
INCHES
MILLIMETERS
MIN NOM MAX MIN NOM MAX
9.91 10.16 10.41 0.390 0.400 0.410
12.45 12.70 12.95 0.490 0.500 0.510
14.99 15.24 15.50 0.590 0.600 0.610
17.53 17.78 18.03 0.690 0.700 0.710
MILLIMETERS
MIN NOM MAX
2.41
0.127
2.29
MIN
INCHES
NOM MAX
2.54 2.67 0.095 0.100 0.105
0.300 0.005
0.012
2.41 2.54 0.090 0.095 0.100
0.33 0.46 0.51 0.013
0.203 0.280 0.381 0.008
see table above
10.11 10.41 10.67 0.398
7.42 7.49 7.57 0.292
1.14
0.41
1.27
-
0°
-
0.018 0.020
0.011 0.015
0.410 0.420
0.295 0.298
1.40 0.040 0.050 0.055
0.89 0.016
0.035
0°
8°
8°
Smart AnalogTM is a Trademark of Crystal Semiconductor Corporation