4000 SERIES
Acapella Optical Modem IC
ACS411CS
ACS411CS Main Features
General Description
The ACS411CS is a complete controller, driver and receiver chipset supporting
full-duplex synchronous transmission up to 51.840Mbps over single/twin
optical fiber. The designer can share the available bandwidth over 1 to 16
main channels.
In addition to the main channels, the ACS411CS provides two independent
maintenance channels with a data rate selectable up to 256kbps. On the
electrical side the ACS411CS has a selectable interface for either NRZ or
the pseudo bipolar data coding types HDB3/AMI/B3ZS/B6ZS/B8ZS.
The ACS411CS has a parallel microprocessor bus interface. This can be
used for device set-up, diagnostics, control and status analysis. Additional
flags for Tx data status, Rx data status and alarm indication for both near
end and far end receive fail are accessible via the uP interface.
Communicating modems automatically maintain synchronization with each
Twin fiber full duplex system using ACS411CS chip set
with external T1/E1 Framer ICs and microprocessor.
* Three chip set supporting full duplex serial transmission over
twin optical fiber, one fiber with WDM.
* Configurable parallel microprocessor bus interface.
* Up to 16 independent synchronous data channels.
1 x OC1 (STS1) @ 51.840Mbps
1 x E3/T3
4 x E2, 7 x T2
16 x E1/T1
* Select between NRZ and pseudo-bipolar HDB3/AMI/B3ZS/
B6ZS/B8ZS input data coding types.
* Incorporates 2 x 256kbps maintenance channels with optiono f
multi channel operation with a framing signal.
*Link budgets of 27dB with Laser + PIN on single mode fiber.
* Conforms to all jitter attenuation, jitter transfer and input jitter
tolerance specification defined by AT&T, ITU-T and Bellcore
recommendations.
* Bit Error Rate (BER) of < 10-10
*ACS9020 available in 64 pin TQFP and ACS4110 available in
176 pin TQFP package.
Twi n Fi ber Link
16 transmit data channels
16 receive data channels
16 transmit data clocks
16 receive data clocks
2 transmit maint. channels
2 receive maint. channels
1 transmit maint. clock
1 receive maint. clock
TPOS1/TNEG1
TPOS16/TNEG16
RPOS1/RNEG1
RPOS16/RNEG16
TCLK(16:1)
RCLK(16:1)
TmD1/RmD1
TmD2/RmD2
TmCLK/RmCLK
ACS411CS
RPOS1/RNEG1
RPOS16/RNEG16
TPOS1/TNEG1
TPOS16/TNEG16
RCLK(16:1)
TCLK(16:1)
RmD1/TmD1
RmD2/TmD2
RmCLK/TmCLK
ACS411CS
LIU inter face
LIU inter face
16to 1 Mux
1to16 Mux
1to16 Mux
16to 1 Mux
µProcessor
8 bit parallel
bus interface
device setup
mode con trol
Tx data sta tu s
Rx data status
status reset
device setup
mode con trol
Tx data sta tu s
Rx data status
status reset
µProcessor
8 bit parallel
bus interface
Preliminary
2
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
PORB
The Power On Reset (PORB) pin resets the device
if forced low for 2ms or more. In normal operation
PORB should be held High. It is recommended that
PORB is connected to VD+ via a 100KΩ resistor
and to GND via a 100nF capacitor.
System Clock
The system clock on the ACS411CS is derived locally
using the on-chip crystal oscillator and multiplying
PLL.
The oscillator (XTO/I) requires the use of a
fundamental parallel resonance crystal with
appropriate padding capacitors. The crystal
specification should be:
Calibration tolerance: +/- 20ppm @ 25°C
Temp. tolerance: +/-20ppm @ -40 to +85°C
Temperature range: -40 to +85°C
Load condition: parallel load 15pF
Padding capacitor: 18-22pF (tune for desired tolerance)
The system clock defines the burst frequency at
which data is transmitted over the optical link via the
optical interface. The receive circuitry within the
ACS4110 recovers the clock from the received data
at the RXDAT inputs and produces a clock that is
synchronised to the incoming data stream. The
system clock must have a maximum tolerance of +/-
50ppm over the desired temperature range.
Optical Operational Modes
The ACS411CS has four optical operational modes,
all supporting twin fiber. The ACS9020 can also
utilise Lasers/LED and PIN combinations, including
a PIN with an internal Trans-Impedence Amplifier
(TIA) controlled by PINRX.
The twin fiber Laser modes in Table 1 may be
converted to single fiber operation simply by
interfacing to Wave Division Multiplexer (WDM)
device indicated by mode 5.
Mode Optical Device
1 Laser and PIN diode without TIA.
2 Laser and PIN diode with integrated TIA.
3 LED and PIN diode without TIA.
4 LED and PIN diode diode with integrated TIA.
5 WDM
Table 1: Optical modes
The ACS411CS comprises a chip set of two/three
(link budget dependent) highly integrated devices,
the ACS9020 and ACS4110. The ACS9020 is an
analogue device and the ACS4110 is predominately
a digital device.
The ACS9020 contains the Laser/LED driver as well
as the PIN receiver circuitry. Since the devices are
transmitting and receiving continuously, for long haul
applications two ACS9020 devices are required, one
configured as the transmitter and the other configured
as the receiver.
The ACS4110 comprises the logic necessary to time
compress and decompress the data, plus clock
recovery and all the logic associated with valid data
transmission and reception and locking status. The
ACS4110 also has a configurable parallel
microprocessor bus interface for device configuration
(control) and status analysis. The device setup is
also possible via the far end (remote control) or
directly via pins for the basic device setup.
For the purpose of this specification the chip-set will
be referred to as the ACS411CS and the individual
devices as the ACS9020 or ACS4110.
For low link budget applications (up to 10dB) two
chips, the ACS9020 analogue IC (including laser
driver and PIN receiver circuitry) and the ACS4110
are sufficient.
For applications requiring a higher link budget (up to
30dB) a three chip solution has to be used, where
the laser driver and PIN receiver circuitry are
separated.
Inter-Modem Coding
The inter-IC coding between communication modems
is 8B10B. Whilst transparent to the user, 8B10B
encoding ensures that there is no DC component in
the signal, and provides frequent data transitions,
factors which ease the task of data recovery and
clock extraction.
The coding rules are continuously checked to ensure
the integrity of the link, and errors are indicated on
the ERRL and ERRC pins
(see section headed
ERRC and ERRL - Error Detection ).
Transmit and Receive functions
Data presented at the near-end TPOS/TNEG is time-
compressed, encoded in the 8B10B format and
transmitted over the fiber link to the far end receiver.
Similarly, data presented at the far-end TPOS/TNEG
is time-compressed, encoded in the 8B10B format
and transmitted over the other fiber link to the near
end.
Acapella Optical Modem IC ACS411CS
3
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Mode 1 - Laser & PIN without integrated TIA
In mode 1, the device is configured for use with a
Laser and a PIN Diode without a TIA. In this
configuration it is important to employ the TIA
available within the ACS9020. The ACS9020 TIA is
activated by setting PINRX = High.
In this configuration, the PIN Diode should be
connected to the PINP/PINN pins so that the TIA/
Post-Amp combination on the ACS9020 is used.
Mode 2 - Laser and & PIN Receiver with a TIA.
In mode 2, the device is configured for use with a
Laser and PIN Diode with an integrated TIA (Pin
Receiver). In this mode it is important to bypass the
TIA on the ACS9020 device.The VP/VN inputs are
activated by setting PINRX = Low.
In this mode, the outputs from the PIN Receiver
should be connected to the VP/VN inputs of the
ACS9020 Post-Amp via AC coupling capacitors as
shown in the diagram below.
Mode 3- LED & PIN without integrated TIA
In mode 3, the device is configured for use with a
LED and a PIN Diode without a TIA. In this
configuration it is important to employ the TIA
available within the ACS9020. The ACS9020 TIA is
activated by setting PINRX = High.
Laser
PIN Diode
LAP
LAN
PINP
PINN
PMN
Mode 1: 3-pin Laser and PIN.
Fiber
Fiber
LED
PIN Diode
LAP
LAN
PINP
PINN
Mode 3: LED and PIN.
Fiber
Fiber
In this configuration, the PIN Diode should be
connected to the PINP/PINN pins so that the TIA/
Post-Amp combination on the ACS9020 is used.
Mode 4 - LED & PIN with a TIA.
In mode 4, the device is configured for use with an
LED and PIN Diode with an integrated TIA (Pin
Receiver). In this mode it is important to bypass the
TIA on the ACS9020 device.The VP/VN inputs are
activated by setting PINRX = Low.
In this mode, the outputs from the PIN Receiver
should be connected directly to the VP/VN inputs of
the ACS9020 Post-Amp via AC coupling capacitors
as shown in the diagram below.
Mode 5 - WDM Bidirectional Device
The device can be configured for use with a WDM
device (with and without a TIA) to realise a single
fiber link. The electrical connections are the same
as those for mode1 and mode2 dependent on
whether the WDM bidirectional device has a TIA
included or not.
If the device has a TIA integrated then the receivers
Positive/Negative differential outputs are connected
to VP/VN respectively via AC coupling capacitors
with PINRX set Low.
Laser
LAP
LAN
PMN
Fiber
Mode 2: 4-pin Laser and PIN with integrated TIA.
Fiber
LAP
PIN Diode
VP
VN -
+
100PF
100PF
LED
LAP
LAN
Fiber
Mode 4: LED and PIN with internal TIA.
PIN Diode
VP
VN -
+
100PF
100PF
Fiber
Preliminary
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ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Wave Division
Multiplexing Device
Laser
PIN Diode
LAP
LAN
PINP/VP
PINN/VN
PMN
Single
Fiber
WDM device containing 3-pin Laser and PIN.
If the device does not have an integrated TIA then
the PIN Diodes's Cathode/Anode is connected to
PINP/PINN respectively with PINRX set High.
Control of LED Current
To minimise the switching delay, a permenent bias
current is maintained through the LED. A second
current source called the modulation current varies
the intensity of the output light power such that:
Optical Low current = Bias current.
Optical high current = Bias current + Modulation current
Unlike Lasers, LED's have a linear relationship
between current and output light power. Also, the
output power of LEDs does not vary significantly with
temperature. Therefore, LEDs are driven with a
predetermined biased current and modulation current
fixed by the resistors between RBIASET and GND
and RMODSET and GND respectively. In order to
fix the modulation current the signal MODFIX should
be set = High.
The bias current is determined by a resistor
connected between pin RBIASSET and Ground.The
bias current can be calculated from the formula
below:
I
(LAN) (BIAS) = 50/ RRBIASSET
Where R RBIASSET > 1Kohm, tolerance +/- 20%
I = Amps
The modulation current is determined by a resistor
connected between pin RMODSET and Ground.The
modulation current can be calculated from the formula
below:
I (LAN) (MOD) = 100/ RRMODSET
Where RRMODSET > 1Kohm, tolerance +/- 20%
I = Amps
When setting the bias current and the modulation
current it is important to ensure that the sum of the
component currents do not exceed 100 mA.
I (LAN) = I (BIAS) + I (MOD) <= 100 mA
The bias current and modulation currents should be
set to give the appropraite extinction ratio. The
extinction ratio is the ratio of the optical high power
compared to the optical low power.
Eg. An extinction ratio of 13db, is where the optical
high power is 20 times the optical low power.
Control of LASER Current
To minimise switching the delay, a permenent bias
current is maintained through the LASER. A second
current source called the modulation current varies
the intensity of the output light power such that:
Optical Low current = Bias current.
Optical high current = Bias current + Modulation current
For Lasers, there is a non-linear relationship between
the output power and the applied current. In addition,
Laser output power will vary significantly with
temperarure for a constant current. For these reason
Laser drive current must be controlled so as to
maintain a constant optical output power from the
Laser. The monitor pin resident in the laser converts
the incident light power (typically leaked from the
rear facet of the laser itself) to a monitor current,
which is directly compared to a preset programmed
current (the current flowing through RMODSET). The
Laser drive current is automatically adjusted to
maintain the original preset light level over the
temperature and voltage range. The designer should
be aware that whilst the control loop maintains the
current generated by the monitor-pin within a
tolerance of 2%, there is additional uncertainty
attributed to the monitor-pin's temperature coefficient
of responsivity. Data relating to the Laser
characteristics should be acquired from the Laser
supplier.
The bias current is set in the same way as it is for
the LED driver. The bias current is determined by a
resistor connected between pin RBIASSET and GND.
The bias current can be calculated from the formula
below:
I (LAN) (BIAS) = 50/ RRBIASSET
Where R RBIASSET > 1Kohm, tolerance +/- 20%
I = Amps
Whilst the bias current flowing through the Laser is
fixed, the modulated component is automatically
regulated to maintain a near constant output light
power. In order to activate the automatic regulation
of the modulation current it is important that the pin
MODFIX is set Low.
The monitor-pin current is set by a variable resistor
(RRMODSET) connected between pin RMODSET and
Ground. Acapella recommends that RRMODSET should
comprise a logarithmic potentiometer of value 50
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Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Kohms. It is important that RRMODSET is inserted and
adjusted to its maximum resistance value of 50
Kohms prior to applying power to the ACS9020 for
the first time and prior to following the procedure
detailed in section headed,
Laser Adjustment
Procedure
.
I(PMN - AVERAGE) (BIAS + MOD) = 1/ RRMODSET
Where RRMODSET > 1Kohm, tolerance +/- 20%
TXMON and TxFLG
TXMON is used to monitor the current delivered to
the LED or Laser. TXMON is a current source that
proportionally mirrors the current flow through the
LED or Laser. By placing an appropriate external
resistor RTXMON between TXMON and GND, the
voltage developed (referenced to GND), will be
proportional to the transmit current. During the Laser
setup procedure TXMON should be monitored to
ensure that the Laser manufacturer's maximum
current specification is not exceeded.
The transmit current monitor is a current source
flowing from VDD out of pin TXMON. This current is
representative of the Laser/LED drive current.
ITXMON = IBIAS/50 + IMOD/100
IBIAS is the Low level bias current.
IMOD is the peak Modulation level bias current. The
average modulation current is half this value.
Average drive current, IAVG = (IBIAS + IMOD) /2
Therefore ITXMON = IAVG/50
TXMON may also be employed during normal
operation to continuously check the Laser current.
The voltage developed across RTXMON is compared
within an internally generated reference voltage of
1.25V. In the event that the reference voltage is
exceeded, the TXFLAG is set High, otherwise it is
set Low. In this way, the value of resistor on TXMON
can be chosen to activate TXFLAG at any desired
transmit current
e.g. If RTXMON = 1KW, then TXFLAG will be set if IAVG
exceeds 62.5mA.
If desired, TXFLAG activation can be delayed by
adding a damping capacitor between TXMON and
GND.
Laser Adjustment Procedure
The output power from the Laser should be measured
with an optical power meter during the setup
procedure. In addition TXMON may be monitored to
ensure that manufacturers maximum current limits
are not exceeded during the set-up process. Select
one of the laser drive modes in accordance with the
section headed,
Optical Operational Modes.
Start be setting the current control resistors RRMODSET
and RRBIASSET to their highest values (at least 50Kohm
is recommended).
The bias current is then set to the desired level by
adjusting the variable resistor RRBIASSET. Since the bias
current sets the optical low-level for the Laser, it is
essential that the Laser driver data inputs are set at
a continuous logic low level. The resistor value
(typically a 50K potentiometer) is reduced until the
desired bias current is achieved or until the desired
low-level optical output power is achieved. It should
be understood that since the bias current is fixed
(not regulated), the low level optical output power
will vary across the temperature and voltage range.
Once the bias current is set, the modulation current
maybe set by adusting the variable resistor RRMODSET.
The automatic power regulation circuitry for the
modulation current maintains the average optical
output power and not the peak power. For this reason,
during the set-up process in the absence of the
appication data, it is recommended that the Laser
driver is stimulated with a square wave. Most
application data used in fiber optic transmission is
dc-balanced (equal number of ones and zeros), so a
square-wave is an accurate representation of the
real data.
The resistor value (typically a 50K potenmtiometer)
is reduced until the desired optical-high ouput power
is achieved. The modulation ouput power will then
be regulated such that the average ouput optical
output power (bias + modulation) is mainatined over
the recommended temperature and voltage range.
Receive Monitor RXMON and RXFLAG
The ACS9020 incorporates a power meter which
generates a current source on the RXMON pin, which
is proportional to the received signal strength. A
voltage is generated on an internal 50Kohm resistor
which is continuously compared with an internally
generated reference of 1.25 volts.
The RXFLAG is set when the RXMON voltage
exceeds the 1.25 volt reference. The flag is used to
indicate that there is sufficient signal strength to give
a minimum differential output signal on the receiver
output pins DOUTP and DOUTN. If the voltage on
DOUTP/DOUTN exceeds 500 mV peak-to-peak then
the RXMON voltage will exceed 1.25 Volts and the
RXFLAG will be set.
Because of process tolerances on the internal resistor
and the internally generated reference voltage, the
RXFLAG should be considered only as a guide to
the receive signal strength. The receive threshold
can be adjusted by placing a 1Mohm external
potentiometer between the RXMON pin and Ground.
Preliminary
6
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Transmit monitor TXMON and TXFLAG
TXMON is used to monitor the current delivered to
the LED or Laser. TXMON is a current source that
proportionally mirrors the current flow through the
LED or Laser. By placing an appropriate external
resistor RTXMON between TXMON and GND, the
voltage developed (referenced to GND), will be
proportional to the transmit current. During the Laser
setup procedure TXMON should be monitored to
ensure that the Laser manufacturer's maximum
current specification is not exceeded.
The transmit current monitor is a current source
flowing from VDD out of pin TXMON. This current is
representative of the Laser/LED drive current.
ITXMON = IBIAS/50 + IMOD/100
IBIAS is the Low level bias current.
IMOD is the peak Modulation level bias current. The
average modulation current is half this value.
Average drive current, I AVG = (IBIAS + IMOD) /2
Therefore I TXMON = IAVG/50
TXMON may also be employed during normal
operation to continuously check the Laser current.
The voltage developed across RTXMON is compared
within an internally generated reference voltage of
1.25V. In the event that the reference voltage is
exceeded, the TXFLAG is set High, otherwise it is
set Low. In this way, the value of resistor on TXMON
can be chosen to activate TXFLAG at any desired
transmit current
e.g. If RTXMON = 1KΩ, then TXFLAG will be set if I AVG
exceeds 62.5mA.
If desired, TXFLAG activation can be delayed by
adding a damping capacitor between TXMON and
GND.
Receive Monitor RXMON and RXFLAG
The ACS9020 incorporates a power meter which
generates a current source which is proportional to the
received optical current.
There is an internal resistor of value of 50KΩ +/- 20 %
connected between RXMON and GND which
converts the current into a voltage.
RXMON is compared with 1.25V. If RXMON exceeds
1.25V, then output RXFLAG is set = 1, otherwise
RXFLAG is set = 0. With the internal resistor of
50KΩ. By adding an external parallel resistor
between RXMON and GND, this threshold may be
increased.
Transmission Clock TCLK
There are 16 independent Transmit clocks
TCLK(16:1) on the ACS4110. For the purpose of
this specification, these signals will be referred to
collectively as TCLK. The ACS4110 gives a choice
between internally and externally generated transmit
clocks. When the CKC pin is held Low, the set of
TCLK clocks are configured as outputs producing a
clock at the frequency defined by DR(3:1).
When the CKC pin is held High, the set of TCLK
clocks are configured as inputs, and will accept an
externally produced transmission clock with a
tolerance of up to 250ppm with respect to the
transmission rate determined by DR(3:1).
The data appearing on TPOS/TNEG is valid on the
rising or falling edge of the TCLK clock dependent
on the setting of TRSEL
(see Figure 22. Timing
diagrams)
. This is the case for both internally and
externally generated transmission clocks.
Receive Clock RCLK
There are 16 independent Receive clocks
RCLK(16:1) on the ACS4110. For the purpose of
this specification, these signals will be referred to
collectively as RCLK.
The data appearing on RPOS/RNEG is valid on the
rising or falling edge of the RCLK clock dependent
on the setting of RESEL
(see Figure 22. Timing
diagrams)
. To ensure that the average receive
frequency is the same as the transmitted frequency,
RCLK is generated from a Phase-Lock Loop (PLL)
system (except where master mode has been
selected). The PLL makes periodic corrections to
the output RCLK clock by subtracting or adding a
single crystal clock bit-period, so that the average
frequency of the RCLK clock tracks the average
frequency of the transmit clock of the far-end modem
(or system master clock). This decompression/de-
jittering function is covered in more detail in section
headed,
Jitter Characteristics.
The recovery and de-jittering functions comply to jitter
tolerance and jitter transfer specifications of the
selected data rates. The algorithm that determines
the transfer function and response of the PLLs is
modified (shaped) according to the selected data rate.
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Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
System Frequencies and Clock Generation
The crystal clock frequency and the multiplying factors
of the MPLL are determined by the choice of data
rates. Table 2 lists the required frequencies of the
system.
Mode Data Rate XTAL Fsys
MHz MHz MHz
16 x T1 1.544 23.160 69.480
16 x E1 2.048 22.528 67.584
7 x T2 6.312 23.144 69.432
4 x E2 8.448 22.528 67.584
1 x E3 34.368 22.912 68.736
1 x T3 44.736 22.368 67.104
1 x OC1 51.840 25.920 77.760
Table 2: System frequencies
Data Coding
The main synchronous channels may use any of the
following coding methods: NRZ, AMI, HDB3, B3ZS,
B6ZS and B8ZS. The desired mode is selected by
POL(3:1) input pins, as shown in Table 3.
Data POL3 POL2 POL1
Coding
NRZ 0 0 0
AMI 0 0 1
HDB3 0 1 0
B8ZS 0 1 1
B6ZS 1 0 0
B3ZS 1 0 1
NRZ 1 1 0
NRZ 1 1 1
Table 3: Line coding selection
For Non-Return-to-Zero (NRZ) coding, data is applied
directly to TPOS inputs, and output data appears
only on the RPOS output pins
.
When using NRZ
code, unconnected TNEG input pins will automatically
pull-up to VD+. In addition, the ACS411CS will assert
a continuous Low on redundant RNEG output pins.
AMI, B3ZS, B6ZS, B8ZS and HDB3 coding is
normally bipolar. However, it is possible to interface
with the ACS411CS using two inputs and outputs
rather than a single bipolar interface. Data equivalent
to positive excursions of the bipolar AMI/BxZS/HDB3
signal are applied as a logic High to TPOS, while
data equivalent to negative excursions are applied
as a logic High to TNEG. Similarly, AMI/BxZS/HDB3
positive excursions will appear as a logic High on
RPOS and negative excursions will appear as a logic
High on RNEG.
It is anticipated that most users of the ACS411CS
will interface directly with a E1/T1 framers. All the
popular framers provide POS/NEG bipolar interfaces
which will directly connect to the ACS4110.
If required, a detailed description of the AMI/HDB3/
BxZS coding rules are available from Acapella.
Data Rate Selection
For the purpose of this specification TPN1 represents
the set of signals TPOS1 and TNEG1, and RPN1
represents the set of signals RPOS1 and RNEG1.
See section headed,
Data Coding
for a description
of the coding types.
The maximum recommended crystal (XTAL) is
26.88MHz. An internal multiplier factors the XTAL
frequency by 3. The maximum bandwidth is
51.840MHz (OC1). This bandwidth can be utilised
in various ways, it may be divided up over 1, 4, 7 or
16 channels.
All 16 main channels are completely independent. One
channel consists of the following 6 signals:
Transmit side:
TPOS +ve in bipolar signal or NRZ data
TNEG -ve in bipolar signal TPOS
TCLK transmit clock (internal or external)
Receive side:
RPOS +ve in bipolar signal or NRZ data
RNEG -ve in bipolar signal or NRZ data
RCLK receive clock
The data rate can be selected via the data rate selection
bits DR(4:1), either directly via pins or via the
microprocessor interface. The selection determines
the number of active channels in combination with the
selected crystal frequency and the line data rate in
accordance with Table 4.
DR Pins TCLK Nos. of Tmode
3 2 1 (MHz) channels
1 1 0 1.544 16 16 x T1
1 0 1 2.048 16 16 x E1
1 0 0 6.312 7 7 x T2
0 1 1 8.448 4 4 x E2
0 1 0 34.368 1 1 x E3
0 0 1 44.736 1 1 x T3
0 0 0 51.840 1 1 x OC1
Table 4: Data rate and channel selection
Channels not used in a specific mode are disabled. For
example in 4 x E2 mode channels 1 to 4 are carrying
E2 data rates, and channels 5 to 16 are disabled. All
channels can be disabled individually via the
microprocessor interface, or alternatively via far-end
remote control.
Preliminary
8
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Diagnostic modes (main channel)
The ACS4110 has four diagnostic/configuration modes
implemented for the main channels, configured by
CM(3:1). The following diagnostic / configuration modes
are implemented for the main channels:
- full duplex
- full duplex slave
- full duplex master
- remote loop-back
- local loop-back
The modes are selectable via CM(3:1) either directly
via pins, via the microprocessor interface or via remote
control setup. All modes remote loop-back and local
loop-back are selectable individually for each channel
via the microprocessor interface. Table 5. shows the
selection of diagnostic modes and configurations.
CM(3:1) Diagnostic Mode/Configuration
111 local loop-back initiated from far end
(remote setup only)
110 remote loop-back initiated from far end
101 local loop-back
100 remote loop-back
011 full duplex master
010 full duplex slave
001 full duplex slave/remote full duplex
(remote setup only)
000 full duplex
Table 5: Selection of diagnostic modes
In remote setup (ENRSB=0), the far-end device will be
setup complementary to the near-end device (control
device) according to the Table 6.
CM(3:1) Near End initiate Far End initiate
(Control device) (Remote control device)
111 full duplex local loop-back
110 * remote loop-back
101 local loop-back full duplex
100 remote loop-back *
011 full-fuplex master full-duplex slave
010 full-duplex slave full-duplex master
001 full-duplex slave full-duplex
000 full duplex full duplex
Table 6: Selection of diagnostic modes
* Remote Loop-back Detect.
For a remote loop-back initiated from the far end
device, CM(3:1)=110, the initiating end transmitting
and receiving the data will be setup as full duplex (see
Figure:1).
For remote loop-back, CM(3:1)=100, the remote
loopback is initiated from the near end.
In both cases, the data that is looped back will be the
data applied to the near end device (see Figure:1).
All modes are selectable via CM(3:1) either directly via
pins or via the microprocessor interface. All the
diagnostic modes, including remote loop-back and
local loop-back are selectable individually for each
main and maintenance channel via the microprocessor
interface.
Full-Duplex
In the full-duplex configuration, the RCLK clock of
both devices track the average frequency of the
corresponding TCLK clock of the opposite end of
the link. The receiving Digital-Phase-Lock Loop
(DPLL) system makes periodic adjustments to the
RCLK clock to ensure that the average frequency is
exactly the same as the far-end TCLK clock. In
summary, each TCLK is an independent master clock
and each RCLK a slave of the far-end TCLK clock.
The relationship between TmCLK and RmCLK are
treated similarly.
Full-Duplex Slave
In slave mode, the TCLK and RCLK clock is derived
from the TCLK clock of the far-end modem, such
that their average frequencies are identical. Clearly,
it is essential that only one modem within a
communicating pair is configured in slave mode. The
CKC pin should be forced to GND, so that TCLK is
always configured as an output.
The relationship between TmCLK and RmCLK are
treated similarly. The CKM pin should be forced to
GND, so that TmCLK is always configured as an
output.
Full-Duplex Master
In master mode, the local RCLK clock is internally
generated from the local TCLK clock. The local
TCLK clock may be internally or externally generated.
Master mode is only valid if the far-end device is
configured in slave mode or if the far-end TCLK clock
is derived from the far-end RCLK clock. Only one
modem within a communicating pair may be
configured as a master.
The relationship between TmCLK and RmCLK are
treated similarly.
Local Loopback
In local loopback mode, TPN and TmD data is looped
back inside the near-end modem and is output at its
own RPN and RmD outputs.
Data received from the far-end device is ignored,
except to maintain lock. If concurrent requests occur
for local and remote loopback, local loopback is
selected. The local loopback diagnostic mode is used
to test data flow up to, and back from, the local
ACS4110 and does not test the integrity of the link
itself. Therefore, local loopback operates
independently of synchronisation with a second
modem (i.e. DCD may be High or Low). The local
9
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Remote loop-back initiated by far end modem CM(3:1)=110
Remote loop-back CM(3:1)=100
ACS411CS
twin fiber link
Near-end modem
Far–end modem Loop control
Far-end modem looping back data
TPOS, TNEG, TCLK
RPOS, RNEG, RCLK ACS411CS
CM(3:1) = 110
ACS411CS
twin fiber link
Near-end modem Loop control Far-end modem looping back data
TPOS, TNEG, TCLK
RPOS, RNEG, RCLK ACS411CS
CM(3:1) = 100
Figure 2 : Remote loopback control configurations.
twin fiber link
Near-end modem Loop control
Near end data looped back Far-end modem
TPOS, TNEG, TCLK
RPOS, RNEG, RCLK ACS411CS
CM(3:1) = 101
ACS411CS
local loop-back CM(3:1)=101
local loop-back initiated by far end modem CM(3:1)=111
twin fiber link
Near-end modem
Remote loop control* of far end Far-end modem data loop back
RPOS, RNEG, RCLK
TPOS, TNEG, TCLK
ACS411CS
CM(3:1) = 111
ACS411CS
*Only if near-end in Remore control mode
ENRSB =0
Figure 1: Local loopback control configurations.
Preliminary
10
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
For example: 4 x 16kbps maintenance channels.
select MSEL(3:1) = 010, total available bandwidth on
TMD1 is 64kbps and frame every 4th bit. The "framing"
channel TMD2 is bit locked to the data channel TMD1.
Diagnostic Modes and Configuration
The diagnostic and configuration modes available for
the main channels are also available for the
maintenance channels. CM(3:1) also controls the
maintenance channels, while all modes including
remote loopback and local loopback are also selectable
individually via the microprocessor interface.
Transmit and Receive Clock
The ACS4110 gives the choice between internally or
externally generated TmCLK under the control of the
CKM pin. When the CKM pin is held Low, TmCLK
is configured as an output producing a clock at the
data rate determined by MSEL(3:1). When the CKM
pin is held High, TmCLK is configured as an input,
and will accept an externally produced transmission
clock at the data rate determined by MSEL(3:1).
Input data appearing on the TMD1/2 inputs is latched
into the device on either the rising or falling edge of
the TmCLK clock depending on the setting of TRSEL.
This data appears at the RMD1/2 outputs of the far-
end modem on the rising or falling edge of the
RmCLK clock depending on the setting of RESEL
(
see Figure 21. Timing diagrams
). To ensure that
the average receive frequency is the same as the
transmitted frequency, RmCLK is generated from a
Digital Phase-Lock Loop (DPLL) system.
Whilst the TMD1/RMD1 and TMD2/RMD2
maintenance channels have a fixed phase
relationship with each other, they do not have a fixed
phase relationship with the main TPOS/TNEG data
transmission channels.
loopback test can be initiated via the microprocessor
interface (in all microprocessor modes), giving
independent control for each channel. All channels
can be simultaneously initiated into local loopback
when the microprocessor mode is disabled via the
CM(3:1) pins.
Remote Loopback
In remote loopback mode, both modems are
exercised completely, as well as the Lasers/LEDs
and the fiber optic link. The remote loopback test is
normally used to check the integrity of the entire link
from the near-end (initiating modem).
Whilst a device is responding to a request for remote
loopback from the far-end, requests from the near-
end to initiate remote loopback will be ignored.
The remote back request can be initiated by either
the near end modem (the near-end modem sends a
request to the far-end modem to loopback its received
data) or by the far end modem itself. In both cases
the far end modem loops back the received data to
the near end.
The remote loopback test can be initiated via the
microprocessor interface (in all microprocessor
modes), giving independent control for each channel.
All channels can be simultaneously initiated into
remote loopback when the microprocessor mode is
disabled via the CM(3:1) pins.
Maintenance channel
The ACS4110 offers up to 2 synchronous maintenance
channel consisting of the following signals:
Transmit Side
TMD1 transmit NRZ data/framing
TMD2 transmit NRZ data/framing
TmCLK transmit clock (internal or external)
Receive Side
RMD1 receive NRZ data/framing
RMD2 receive NRZ data/framing
RmCLK receive clock
Maintenance Data Rate Selection
The data rate can be selected via the maintenance
data rate selection bits MSEL(3:1), either directly via
pins or via the microprocessor interface.
TMD1/RMD1 and TMD2/RMD2 support up to 256kbps
synchronous data synchronised to TmCLK/RmCLK.
They can be used as two independent channels giving
a total available bandwidth to 512kbps.
Alternatively, TMD1 or TMD2, together with a specific
data rate selection, can be used to divide the bandwidth
of the remaining maintenance channel into sub-
channels with a certain data rate, defined in Table 7.
MSEL(3:1) Data Rate (kbps)
101 8
100 16
011 32
010 64
001 128
000 256
Table 7: Maintenance Channel Data Rate Selection
11
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
ERRC and ERRL - Error Detection
These signals can be used to give an indication of
the quality of the optical link. Even when a DC signal
is applied to the data, maintenance and TCLK inputs,
the ACS411CS modem transmits data over the link
in each direction at the Fsys system frequency. This
transmit and control data is used to maintain the
timing and synchronisation.
The transmit and control data is constantly monitored
to make sure it is compatible with the 8B10B format.
If a coding error is detected ERRL will go High and
will remain High until reset. ERRL may be reset by
asserting PORB, or by removing the fiber optic cable
from one side of the link thereby forcing the device
temporarily out of lock.
ERRC produces a pulse on detection of each coding
error. These pulses may be accumulated by means
of an external electronic counter. In the
microprocessor modes, the value on an internal
accumulating 8 bit counter can be read via the bus
interface address 0x1D.
Please note that ERRL and ERRC detect 8B10B
coding errors and not data errors, nevertheless
because of the complexity of the coding rules
employed on the ACS411CS, the absence of detected
errors on these pins will give a good indication of a
high quality link.
TmCLK and the reference clock for the (digital) clock
recovery and de-jittering PLLs (DPLL) for RmCLK
are derived digitally from the system clock for
256kbps by the division factors shown in Table 8. If
lower data rates than 256kbps are selected, the
256kHz clock will be divided down by a factor 2/4/8/
16/32 determined by MSEL(3:1).
Mode FSys/256 kbps
16 x T1 271.40625
16 x E1 264
7 x T2 271.21875
4 x E2 264
1 x E3 268.5
1 x T3 262.125
1 x OC1 303.75
Table 8: System Clock Division Factors for
Maintenance Clock Generation (256kbps)
Preliminary
12
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Microprocessor Interface
Bus Interface Mode Selection
The ACS4110 incorporates an 8-bit parallel
microprocessor bus interface, which can be configured
for the following modes via the bus interface mode
control pins UPSEL(3:1) as defined in Table 9.
UPSEL(3:1) Mode Description
111 (7) OFF Interface disabled
110 (6) OFF Interface disabled
101 (5) SERIAL Serial uP bus interface
100 (4) MOTOROLA Motorola interface
011 (3) INTEL Intel compatible bus interface
010 (2) MULTIPLEXED Multiplexed bus interface
001 (1) EPROM EPROM read mode
000 (0) OFF Interface disabled
Table 9: Microprocessor Interface Mode Selection
Note: Bit 0 is the least significant bit for all modes used
here, and the byte structure complies to little endian
format (byte 0 is least significant and stored at lowest
address).
In OFF Mode, the bus interface is disabled. Control of
the device is solely via I/O pins. This will result in limited
programmability, as for example individual set-ups for
remote loop-back and local loop-back for each channel
are not possible, only a collective one. In this mode, all
BUS I/O pins are tri-stated or used as additional input
pins (ie. POL(3:1), CKLOCAL).
EPROM mode
The EPROM mode (UPSEL = 1) enables the device to
read its set-up from a memory device. An internal state
machine controls the access to the memory. All
addresses in the memory map are read, and the device
is set up according to the corresponding data. The
access time is scaled to interface with the AMD
AM27C020 at lowest speed (250ns) specification.
The valid read addresse 0, 0xAA is used to check if a
memory device is actually attached to the device. If no
memory is attached, the bus interface reverts to the
default OFF mode. All other read addresses are not
valid. The bus interface pins used in EPROM mode are
defined in Table 10.
Pin Dir Description
CSB O Active low chip select/output enable
A(4:0) O Address output to EPROM
AD(7:0) I Data input from EPROM
Table 10: uP Bus Interface Pins for EPROM mode.
MULTIPLEXED mode
The MULTIPLEXED mode (UPSEL = 2) enables the
ACS4110 to interface with a microprocessor using a
combined multiplexed address/data bus. The bus
interface pins are defined in Table 11.
Pi n Dir Description
CSB I Active low chip select
ALE I Address latch enable
RDB I Active low read enable
WRB I Active low write enable
AD(7:0) IO Address / Data bus
RDY O Ready
Table 11: uP Bus Interface Pins for MULTIPLEXED mode.
INTEL mode
The INTEL mode (UPSEL = 3) enables the ACS4110
to interface with a Intel 80x86 type microprocessor
bus. The bus interface pins used are defined in Table
12.
Pi n Di r Description
CSB I Active low chip select
RDB I Active low read enable
WRB I Active low write enable
A(4:0) I Address bus
AD(7:0) IO Data bus
RDY O Ready
Table 12: uP Bus Interface Pins for INTEL mode.
MOTOROLA mode
The MOTOROLA mode (UPSEL = 4) enables the
ACS4110 to interface with a Motorola 680x0 type
microprocessor bus. The bus interface pins used are
defined in Table 13.
Pi n Dir Description
CSB I Active low chip select
WRB I Read / write bar select
A(4:0) I Address bus
AD(7:0) IO Data bus
RDY O Active low data transfer
acknowledge (DTACK)
Table 13: uP Bus Interface Pins for MOTOROLA mode.
13
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
SERIAL mode
The SERIAL mode (uPSEL = 5) enables the
ACS4110 to interface with a serial microprocessor
bus. The bus interface pins are defined in Table 14.
Pin Dir Description
CSB I Active low chip select
ALE I = SCLK: Serial interface clock
A(1) I = CLKE: Active SCLK edge selection
control bit
A(0) I = SDI: Serial data input
AD(0) O = SDO: Serial data output
Table 14: uP Bus Interface Pins for SERIAL mode.
Remote Control
The device setup of one modem can be over-ridden
with the device set up from the other modem when
remote control is enabled from the ENRSB pin. To
enable remote control mode, ENRSB pin is held Low
(Logic 0). If a modem is set up in remote control, the
data from the control modem overides the local
microprocessor interface or pin set-up of the remote
controlled modem. The signals that will be over-ridden
are defined in Table 15.
Name Description
ch_enb(16:1)Channel enable defined in local microprocessor
for individual channel setup
DR(3:1) Data rate select
POL(3:1) Line code polarity select
CM(2:1) Configuration mode(full-duplex/master/slave)
TRSEL Clock edge select for transmit clocks
RESEL Clock edge select for receive clocks
CKM Clock direction select maintenance channel
CKC Clock direction select main channels(combined)
MSEL(3:1) Maintenance channel data rate select
Table 15: Remote Control Device Setup.
Remote control is only possible in one direction (only
one modem allowed with ENRSB = 0).
ACS411CS
twin fiber link
ENRSB = 0
C on tro l Mo dem
ACS411CS
Rem ot e Control le d Modem
ENRSB = 1
CKLOCAL
CM(3:1), POL(3:1)
CKC, CKM, TRSEL, RESEL
DR(3:1), MSEL(3:1)
CM(3:1), POL(3:1)
DR(3:1), MSEL(3:1)
CKC, CKM, TRSEL, RESEL
CKLOCAL=0:
CKC, CKM, TRSEL, RESEL
CKLOCAL=1:
The near-end modem has to be setup as the control
device (ENRSB=0) in order to configure the far-end by
remote control. If both modems are setup as control
devices (ENRSB=0), data transmission and reception
will be disabled.
When in remote setup, the signal CKLOCAL selects
whether the Tx/Rx clock settings (CKC, CKM, RESEL,
TRSEL, trsel_m and resel_m) should be taken from
the controlling device (CKLOCAL=0) or locally
(CKLOCAL=1).
The diagram in Figure 1 shows the configurations in
Remote Control mode.
Figure 3: Remote Control Mode and ENRSB.
Preliminary
14
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
uP Interface timing - MULTIPLEXED mode
In MULTIPLEXED mode, the device is configured to
interface with a microprocessor using a multiplexed
address/data bus. The following figures show the
timing diagrams of write and read accesses for this
mode.
The RDY low time Trdy is at least 2 CLKX cycles
after WRB/RDB going low.
Figure 4: Read access timing in MULTIPLEXED Mode.
AD address X
RDY
CSB
RDB
Z Z
WRB
data X
ALE
tsu1
tsu2
td1
td2 td3
td4
td5
tpw2
tpw1
tpw3
th1
th2
th3
tp1
Symbol Parameter Min Typ Max
tsu1 Setup AD address valid to ALE ↓5 *
tsu2 S etup C SB ↓ to RDB ↓0
td1 Delay RDB ↓ to AD data valid 10 *
td2 Delay C SB ↓ to RDY active 10 *
td3 Delay RDB ↓ to RDY ↓10 *
td4 Delay RDB ↑ to AD data High-Z 10 *
td5 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 R D B low t ime 6 0
tp w2 RDY lo w time 2 0 6 0
t p w3 AL E high t ime 1 0 *
th1 Hold AD address valid after ALE ↓5 *
th2 Hold CSB low after RDB ↑0
th3 Hold RDB low after RDY ↑0
tp1 Time be tween ALE ↓ and RDB ↓0 *
tp2 Time between consecutive accesses
(RD B ↑ to ALE ↑)60
Note: preliminary timing information. Timing values marked with * TBA.
15
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 5: Write access timing in MULTIPLEXED Mode.
AD address X
RDY
CSB
RDB
Z Z
WRB
data X
ALE
tsu1
tpw3
tsu2
tsu3
td1 td2 td3
tpw1
tpw2
th1
th2
th3
th4
tp1
Symbol Parameter Min Typ Max
tsu1 Setup AD address valid to ALE ↓5 *
tsu2 S etup C SB ↓ to WRB ↓0
tsu3 Setup AD data valid to WRB ↑10 *
td1 Delay C SB ↓ to RDY active 10 *
td2 Delay WRB ↓ to RDY ↓10 *
td3 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 W R B lo w t ime 6 0
tp w2 RDY lo w time 2 0 6 0
t p w3 AL E high t ime 1 0 *
th1 Hold AD address valid after ALE ↓5 *
th2 Hold CSB low after WRB ↑0
th3 Hold WRB low after RDY ↑0
th4 AD data hold valid after WRB ↑5 *
tp1 Time be tween ALE ↓ and WRB ↓0 *
tp2 Time between consecutive accesses
(WRB ↑ to ALE ↑)60
Note: preliminary timing information. Timing values marked with * TBA.
Preliminary
16
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
uP Interface timing - INTEL mode
In INTEL mode, the device is configured to interface
with a microprocessor using a 80x86 type bus. The
following figures show the timing diagrams of write
and read accesses for this mode.
The RDY low time Trdy is at least 2 CLKX cycles
after WRB/RDB going low.
Figure 6: Read access timing in INTEL Mode.
Note: preliminary timing information. Timing values marked with * TBA.
AD
RDY
CSB
RDB
Z Z
WRB
data
Aaddress
tsu1 tsu2
td1
td2
Z
td3 tpw2
tpw1
td4
td5
Z
th1
th2
th3
Symbol Parameter Min Typ Max
tsu1 Setup A valid to CSB ↓0
tsu2 S etup C SB ↓ to RDB ↓0
td1 Delay RDB ↓ to AD valid 10 *
td2 Delay C SB ↓ to RDY active 10 *
td3 Delay RDB ↓ to RDY ↓10 *
td4 Delay RDB ↑ to AD High-Z 10 *
td5 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 R D B low t ime 6 0
tp w2 RDY lo w time 2 0 6 0
th1 Hold A valid after RDB↑0
th2 Hold CSB low after RDB ↑0
th3 Hold RDB low after RDY ↑0
tp Time between consecutive accesses
(RD B ↑ to RDB ↓ o r RDB ↑ to
W RB ↓)60
17
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 7: Write access timing in INTEL Mode.
Note: preliminary timing information. Timing values marked with * TBA.
AD
RDY
CSB
RDB
Z Z
WRB
data
Aaddress
tsu1 tsu2
tsu3
td1 td2 td3
tpw 1
tpw 2
th1
th2
th3
th4
Symbol Parameter Min Typ Max
tsu1 Setup A valid to CSB ↓0
tsu2 S etup C SB ↓ to WRB ↓0
tsu3 Setup D valid to WRB ↑10 *
td1 Delay C SB ↓ to RDY active 10 *
td2 Delay WRB ↓ to RDY ↓10 *
td3 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 W R B lo w t ime 6 0
tp w2 RDY lo w time 2 0 6 0
th1 Hold A valid after WRB ↑5 *
th2 Hold CSB low after WRB ↑0
th3 Hold WRB low after RDY ↑0
t h4 A D hold valid af t e r W R B ↑5 *
tp Time between consecutive accesses
(WRB ↑ to WRB ↓ o r W RB ↑ to
RDB ↓)60
Preliminary
18
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
uP Interface timing - MOTOROLA mode
In MOTOROLA mode, the device is configured to
interface with a microprocessor using a 680x0 type
bus. The following figures show the timing diagrams
of write and read accesses for this mode.
The Dtack high time Trdy is at least 2 CLKX cycles
after CSB going low.
Figure 8: Read access timing in MOTOROLA Mode.
Note: preliminary timing information. Timing values marked with * TBA.
AD
CSB
WRB
data
Aaddress X
ZZ
XX
RDY
(
DTACK
)
Z Z
tsu1
tsu2
td1
td2
td3
td4
tpw 1
tpw 2
th1
th2
th3
Symbol Parameter Min Typ Max
tsu1 Setup A valid to CSB ↓0
tsu2 Setup WRB valid to CSB ↓5 *
td1 Delay C SB ↓ to AD valid 10 *
td2 Delay C SB ↓ to DTAC K ↑10 *
td3 Delay C SB ↑ to AD High-Z 10 *
td4 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 CSB lo w t ime 6 0
tp w2 DTAC K high time 2 0 6 0
th1 Hold A valid after CSB↑0
th2 Hold WRB high after CSB ↑5 *
th3 Hold CSB low after DTACK ↓0
tp Time between consecutive accesses
(CSB ↑ to C S B ↓)60
19
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 9: Read access timing in MOTOROLA Mode.
Note: preliminary timing information. Timing values marked with * TBA.
AD X
RDY
(DTACK)
CSB
Z Z
WRB
data X
Aaddress X
X X
tsu2
tsu1
tsu3
td1 td2
tpw 1
tpw 2
th1
th2
th3
th4
Symbol Parameter Min Typ Max
tsu1 Setup A valid to CSB ↓0
tsu2 Setup WRB valid to CSB ↓5 *
tsu3 Setup AD valid to CSB ↑10 *
td1 Delay C SB ↓ to DTAC K ↑10 *
td2 Delay C SB ↑ to RDY High-Z 10 *
t p w 1 CSB lo w t ime 6 0
tp w2 DTAC K high time 2 0 6 0
th1 Hold A valid after CSB ↑5 *
th2 Hold WRB low after CSB ↑5 *
th3 Hold CSB low after DTACK↓0
th4 Hold AD valid after CSB↑5 *
tp Time between consecutive accesses
(C SB - to C SB ↓)60
Preliminary
20
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
uP Interface timing - SERIAL mode
In SERIAL mode, the device is configured to interface
with a serial microprocessor bus. The following
figures show the timing diagrams of write and read
accesses for this mode.
During read access the output data sdo (AD(0)) is
clocked out on the rising edge of SCLK (ALE) when
the active edge selection control bit CLKE (A(1)) is
0, and on the falling edge when CLKE is 1. Address,
read/write control bit and write data are always
clocked into the interface on the rising edge of SCLK.
Both input data sdi and clock SCLK are oversampled
, filtered and synchronized to the system clock CLKX.
The serial interface clock (SCLK) is not required to
run when no access is performed (CSB = 1).
Figure 10: Read access timing in SERIAL Mode.
Note: preliminary timing information. Timing values marked with * TBA.
CSB
ALE = SCLK
A(0) = SDI R/W A1 A2 A4
A3 A5 A6
AD(0) = SDO D0 D2 D3 D5
D4 D6
tsu1
tsu2
th1
th2
tpw 1
tpw 2
td1 td2
ZZ
D1
Symbol Parameter Min Typ Max
tsu1 Setup SDI valid to SCLK ↑10 *
tsu2 S etup C SB ↓ to S C LK ↑10 *
th1 Hold SDI to SCLK ↑10 *
th2 Hold SCLK ↑ to C SB ↑10 *
t p w 1 S CL K lo w t ime 2 40
t p w2 S C LK high time 2 4 0
td1 De lay S C LK ↑ (S CLK ↓ for
CLKE = 1) to SDO valid 20 *
td2 Delay C SB ↑ t o S D O H igh-Z 1 2 0
tp Time between consecutive accesses
(CSB ↑ to C S B ↓ )250
21
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
CSB
ALE = SCLK
A(0) = SDI
tsu1
tsu2
th1
th2
tpw 1
tpw 2
A0R/W A1 A2 A4A3 A5 A6 D1
D0 D2 D3 D5D4 D6 D7
AD(0) = SDO Z
Figure 11: Write access timing in SERIAL Mode.
Note: preliminary timing information. Timing values marked with * TBA.
Symbol Parameter Min Typ Max
tsu1 Setup SDI valid to SCLK ↑10 *
tsu2 S etup C SB ↓ to S C LK↑10 *
th1 Hold SDI to SCLK ↑10 *
th2 Hold SCLK ↑ to C SB ↑10 *
t p w 1 S CL K lo w t ime 2 40
t p w2 S C LK high time 2 4 0
tp Time between consecutive accesses
(CSB ↑ to C S B ↓ )250
uP Interface timing - EPROM mode
In EPROM mode, the ACS4110 takes control of the
bus as master, and reads the device set-up from an
AMD AM27C020 type EPROM at lowest speed
(250ns) after device start-up (system reset). The
EPROM access state machine in the up interface
sequences the accesses. The following figures show
the timing diagrams of the read access for this mode.
For a more detailed timing specification, see AMD
Am27C020 data sheet, July 1993, p. 2-95.
If the microprocessor interface is enabled (UPSEL /
= 0), the default start-up values are taken over from
the pin values as default during reset for the following
control pins:
CM(3:1)
CKC, CKM, TRSEL , RESEL
MSEL(3:1), ENRSB
DR(3:1)
Figure 12: Read access timing in EPROM Mode.
Note: preliminary timing information. Timing values marked with * TBA.
AD
CSB (= OEB)
data
Aaddress
ZZ
t
acc
Symbol Parameter Min Typ Max
tacc Delay C SB ↓ or A c hange t o AD valid - - 59 0
Preliminary
22
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Address Bit Access Name Description
0x00 7-0 R id<7:0> Device identification number.
0x01 7-0 R/W ch_enb<8:1> Channel enable (active low) for channels 1 to 8.
0x02 7-0 R/W ch_enb<16:9> Channel enable (active low) for channels 9 to 16.
0x03 7-0 R/W cm1<8:1> Configuration mode CM bit 1 for channels 1 to 8.
0x04 7-0 R/W cm1<16:9> Configuration mode CM bit 1 for channels 9 to 16.
0x05 7-0 R/W cm2<8:1> Configuration mode CM bit 2 for channels 1 to 8.
0x06 7-0 R/W cm2<16:9> Configuration mode CM bit 2 for channels 9 to 16.
0x07 7-0 R/W cm3<8:1> Configuration mode CM bit 3 for channels 1 to 8.
0x08 7-0 R/W cm3<16:9> Configuration mode CM bit 3 for channels 9 to 16.
0x09 7-0 R/W pol1<8:1> Line code polarity POL bit 1 for channels 1 to 8.
0x0A 7-0 R/ W pol1<16:9> Line code polarity POL bit 1 for channels 9 to 16.
0x0B 7-0 R/W pol2<8:1> Line code polarity POL bit 2 for channels 1 to 8.
0x0C 7-0 R/W pol2<16:9> Line code polarity POL bit 2 for channels 9 to 16.
0x0D 7-0 R /W pol3<8:1> Line code polarity POL bit 3 for channels 1 to 8.
0x0E 7-0 R/W pol3<16:9> Line code polarity POL bit 3 for channels 9 to 16.
0x0F 7-0 R/W ckc<8:1> Clock direction select for channels 1 to 8.
0x10 7-0 R/W ckc<16:9> Clock direction select for channels 9 to 16.
0x11 7-0 R/W trsel<8:1> Transmit clock edge select for channels 1 to 8.
0x12 7-0 R/W trsel<16:9> Transmit clock edge select for channels 9 to 16.
0x13 7-0 R/W resel<8:1> Receive clock edge select for channels 1 to 8.
0x14 7-0 R/W resel<16:9> Receive clock edge select for channels 9 to 16.
0x15 7 -
6-4 R/W cm_m<3:1> Configuration mode CM for maintenance channel.
3 R/W CKLOCAL Local Tx/Rx CLK setup in remote control mode
2 R/W CKM Clock direction select maintenance channel.
1 R/W trsel_m Transmit clock edge select for maintenance channel.
0 R/W resel_m Receive clock edge select for maintenance channel.
0x16 7 -
6-4 R /W MSEL<3:1> Maintenance channel data rate select.
3 R/W ENRSB Enable remote control setup.
2-0 R /W DR<3:1> Data rate select.
0x17 7-0 R rl_det<8:1> Near-end remote loop-back detect channels 1 to 8.
0x18 7-0 R rl_det<16:9> Near-end remote loop-back detect channels 9 to 16.
0x19 7-0 R ll_det<8:1> Far-end local loop-back detect channels 1 to 8.
0x1A 7-0 R ll_det<16:9> Far-end local loop-back detect channels 9 to 16.
0x1B 7-2 -
1 R rlm_det Near-end remote loop-back detect for maintenance channel.
0 R llm_det Far-end local loop-back detect for maintenance channel.
0x1C 7 R DCD Data carrier detect status.
6 R LOSS Loss of signal status.
5 R/W ERRL Error latch.
4-
3 R/W fail_ne Alarm indication for near-end receive fail.
2 R/W fail_fe Alarm indication for far-end receive fail.
1 R resync_ne Near-end device has entered re-synchronization.
0 R resync_fe Far-end device has entered re-synchronization.
0x1D 7-0 R /W errc<7:0> 8-bit saturating error counter (reset by write).
0x1E 7-0 R/W tm<7:0> Test mode select.
0x1F 7-0 -
Table 15: Memory Map
Memory Map
Table 15 shows the memory map of the ACS4110. The
location names are chosen to match the corresponding
pin names. Signals not directly equivalent to pins are in
lower case.
The device identification number id<7:0> on address
0x00 is used in EPROM mode to check if an external
memory device is connected. The value to be
programmed is 0xAA.
The whole chip set-up except DR<3:1> can be
controlled individually for each channel.
The error counter errc<7:0> (address 0x1D) is an 8-bit
saturating counter for the ERRC error pulse. A write of
a 0x00 mask to this address clears the counter to 0x00.
The status signals ERRL, fail_ne, fail_fe can also be
cleared by writing a 0 to the specific bit in the address.
For example, writing a mask of 0xDF to address 0x1C
clears the ERRL signal, but leaves other status signals
unchanged.
If the microprocessor interface is enabled (UPSEL /=
0), the default start-up values of all control bits except
POL(3:1) and CKLOCAL are taken over from the pin
values as default during reset.
23
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Laser/LED Considerations
Since LEDs or Lasers from different suppliers may
emit different wavelengths, it is recommended that
the Lasers/LEDs in a communicating pair of modems
are obtained from the same supplier. Acapella will
assist with contact names and addresses on request.
Power Supply Decoupling
The ACS9020 contains a highly sensitive amplifier,
capable of responding to extremely low current levels.
To exploit this sensitivity it is important to reduce
external noise to a low level compared to the input
signal from the Laser/LED. The modem should have
an independent power trace to the point where power
enters the board.
The Laser/LED should be sited very close to the
PMN, PINP, PINN, LAN and LAP pins. A generous
ground plane should be provided, especially
surrounding the sensitive PINP and PINN tracks from
the ACS9020 pins to the optical component. The
modem should be protected from EMI/RFI sources
in the standard ways.
LOSS ( Loss Of Synchronisation)
There are two conditions that will make LOSS go to
Logic 1. These are:
i) Loss of synchronisation - synchronisation windows
incorrectly aligned i.e DCD=0.
ii) 64 received symbols break the 8B10B encoding
rules in a sequence of 256 symbols.
In order to return LOSS to the Logic 0 state the
following criteria must be met:
i) The devices must be synchronised -
synchronisation windows correctly aligned i.e DCD=1.
ii) There are no received symbols in a sequence of
256 symbols which break the 8B10B coding rules.
Figure 13: Power supply considerations.
Place all power supply inductors and
decoupling capacitors as close to the
ACS9020 device as possible.
L = 47 µH R < 1Ω
GND
100nF
L = 47 µH R < 1Ω
L = 47 µH R < 1Ω
VDD VDD VDD
+5V
100 µF
+
100 nF
(GND) 0V
VDD
L = 47 µH R < 1Ω
100nF
GND
VB
TXVDD
RXGND
TXGND
GND1
GND2 RXVDD1
RXVDD2
PLLVDD
VDD
GND
100nF
VDD
GND GND
VD+
GND
GND
ACS9020
(2 off)
ACS4110
GND
100nF
GND
100nF
GND
100nF
VDD
VA+
GND
VB
100nF
Place all power supply decoupling
capacitors as close to the
ACS4110 device as possible.
VD+ pins are 6, 38, 52,
82, 85, 94, 105, 139, 161,
162
GND pins are 5, 37, 51, 81,
84, 108, 122, 123, 124, 128,
130, 138, 159, 160
GND pins are 9, 24, 42, 58
GND GND
Preliminary
24
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Twin Fiber LASER link (1310nm Laser and PIN)
Link Budget Example (Rtset set so LASER launch current = 25 mA peak)
Fiber type Glass (single mode)
Fiber size 9 micron
Minimum transmit couple power to fiber (µW) 1000
Minimum PIN responsivity (A/W) 0.8
Minimum ACS9020 sensitivity (nA) 1500
Minimum input power to ACS9020 amplifier (µW) 4
Link budget (dB) (single mode fiber attenuation = 0.3 dB/km) 27
Twin Fiber LED link (880nm LED + PIN)
Link Budget Example (Rtset set so LED launch current = 100 mA peak)
Fiber type Glass (multimode)
Fiber size 62.5micron
Minimum transmit couple power to fiber (µW) 100
Minimum PIN responsivity (A/W) 0.1
Minimum ACS9020 sensitivity (nA) 1500
Minimum input power to ACS9020 amplifier (µW) 20
Link budget (dB) (multi mode fiber attenuation = 3 dB/km) 8.24
Link Budgets
The link budget is the difference between the power
coupled to the fiber via the transmit Laser/LED and
the power required to realise the minimum input-
amplifier current via the receive PIN/LED. The link
budget is normally specified in dB, and represents
the maximum attenuation allowed between
communicating Lasers/LEDs. The budget is utilised
in terms of the cable length, cable connectors and
splices. It usually includes an operating margin to
allow for degradation in LASER/LED performance.
The power coupled to the cable is a function of the
efficiency of the Laser/LED, the current applied to
the Laser/LED and the type of the fiber optic cable
employed.
Single Fiber LASER link (1310nm and 1510nm WDM device)
Link Budget Example (Rtset set so LASER launch current = 25 mA peak)
Fiber type Glass (single mode)
Fiber size 9 micron
Minimum transmit couple power to fiber (µW) 1000
Minimum PIN responsivity (A/W) 0.8
Minimum ACS9020 sensitivity (nA) 1500
Minimum input power to ACS9020 amplifier (µW) 4
Link budget (dB) (single mode fiber attenuation = 0.3 dB/km) 27
Figure 14: Link bugdet examples.
25
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Jitter Characteristics
The receive path includes a Phase Locked Loop block,
which provides an independent PLL for each
transmission channel. The purpose of each PLL is to
regenerate the clock signal such that it tracks the
transmit clock of the far end modem. The PLL will also
attenuate the jitter present in the received data stream.
For E1, E2, T1 and T2 modes, the PLL algorithm
implemented is entirely digital. For E3, T3 and OC1/
STS1 modes, the PLL block utilised a mixed signal PLL
algorithm. The mixed signal PLL does not require the
use of external tuning components.
T1 Jitte r Tol e rance
0.1
1
10
100
1000
1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05
T1 Jitte r Transfer
-60
-50
-40
-30
-20
-10
0
1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05
The dynamic range of all PLL algorithms is +/- 500ppm.
The dynamic range is used to accommodate oscillator
frequency differences between the two communicating
modems, as well as any jitter and wander present in the
received data stream.
The jitter characteristics for the ACS4110 is independent
of the binary content of the transmitted data stream.
T1 Jitter specification
When configured for T1 operation, the Jitter Tolerance
and Jitter Transfer performance conforms to that
specified in AT&T Publication 62411.
Figure 15: T1 Jitter specifications.
Preliminary
26
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
T2 and T3 Jitter specification
When configured for T2 operation, the Jitter Tolerance
performance exceeds that specified in both ITU-T
G.824 and Bellcore GR-499-CORE.
When configured for T3 operation, the Jitter Tolerance
performance exceeds that specified in both ITU-T
G.824 and Bellcore GR-499-CORE.
In the absence of input jitter, the output jitter generated
from the mixed signal PLL after band pass filtering
from 12kHz to 400kHz is 0.07UIpp.
Figure 16: T2 and T3 Jitter specifications.
T2 Jitte r Tol e rance
0.01
0.1
1
10
100
1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05
G824
GR-499-CORE
T3 Jitte r Tol e rance
0.01
0.1
1
10
100
1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
G824
GR-499-CORE
27
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
E1 Jitter specification
When configured for E1 operation, the Jitter Tolerance
performances exceeds that specified in ITU-T G.823.
The Jitter Transfer performance exceeds that specified
in ITU-T G.736.
With reference to ITU-T G.736, section 6.1.3; in the
case where the timing signal is derived from an incoming
2048kbit/s signal having no jitter, the output jitter
should not exceed 0.10 UIpp when it is measured in the
frequency range 20Hz to 100kHz.
Figure 17: E1 Jitter specifications.
E1 Jitte r Tolerance
0.1
1
10
100
1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05
E1 Jitte r Transfer
-60
-50
-40
-30
-20
-10
0
10
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05
Preliminary
28
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
E2 Jitter specification
When configured for E2 operation, the Jitter Tolerance
performance exceeds that specified in ITU-T G.823.
In the absence of input jitter, the output jitter generated
from the Digital PLL for E2 operation is:
Frequency band Output Jitter
20Hz to 400kHz 0.7UIpp
80kHz to 400kHz 0.09UIpp
Figure 18: E2 Jitter specifications.
E2 Jitte r Tolerance
0.1
1
10
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
E2 Jitte r Transfer
-60
-50
-40
-30
-20
-10
0
10
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
29
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
E3 Jitter specification
When configured for E3 operation, the Jitter Tolerance
performance exceeds that specified in ITU-T G.823.
Output Jitter Generation after band pass filtering 10
kHz to 800kHz.
Figure 19: E3 Jitter specifications.
E3 Jitte r Tolerance
0.1
1
10
1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
E3 Jitte r Transfer
-60
-50
-40
-30
-20
-10
0
10
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
Preliminary
30
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
OC1/STS1 Jitter specification
When configured for OC1/STS1 operation, the Jitter
Tolerance and Jitter Transfer performance exceeds
the requirements specified in Bellcore GR-253-CORE.
In the absence of input jitter, the output jitter generated
from the mixed signal PLL after band pass filtering
from 12kHz to 400kHz is 0.07UIpp.
Figure 20: OC1/STS1 Jitter specifications.
OC1/STS 1Jitte r Tol e rance
0.1
1
10
100
1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
OC1/STS 1 Jitte r Transfer
-60
-50
-40
-30
-20
-10
0
10
1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
31
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 21: Timing diagrams
TmCLK and RmCLK clock pulse widths
Transmit set-up and hold times Receive set-up and hold times
TmCLK RmCLK
The active RmCLK edge is defined by input RESEL.
twl
twh
The active TmCLK edge is defined by input TRSEL.
tsut tht tsur thr
TmD1, TmD2 RmD1, RmD2
90 %
90 %
10 % 10 %
Figure 22: Timing diagrams
TCLK and RCLK clock pulse widths Digital outputs rise and fall times
Transmit set-up and hold times Receive set-up and hold times
RCLK
The active RCLK edge is defined by input RESEL.
tr
t
f
twl
twh
The active TCLK edge is defined by input TRSEL.
tsut tht tsur thr
TPOS/TNEG RPOS/RNEG
TCLK
Preliminary
32
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 23:
Diagram showing ACS9020 and ACS4110
configuration for twin fiber Laser + PIN.
TPOS(16:1)
TNEG(16:1)
TCLK(16:1)
TmD1
TmD2
TmCLK
MSEL(3:1)
CM(3:1)
DR(3:1)
RESEL
TRSEL
CKC
CKM
CONTX
ENRSB
UPSEL(3:1)
ALE
RDB
WRB
CSB
A(4:0)
AD(7:0)
PORB
RPOS(16:1)
RNEG(16:1)
RCLK(16:1)
RmD1
RmD2
RmCLK
TXDATN
TXDATP
ENTX
RXDATN
RXDATP
ERRC
ERRL
DCD
LOSS
RDY
VD+
GND
VA+
100nF
100KΩ
VDD VB
ACS4110
DOUTN
DOUTP
ENRXB
ENTX
ENCOFFB
PINP
PINN
RXMON
Laser
Fiber
PIN Diode
Fiber
100 nF
100 nF
10KΩ
1MΩ
10 nF
CAGC
COFFSET
RSET
VREF
10 nF
10 nF
10 nF
1 nF
220Ω
220Ω
L = 47 µH R < 1Ω
GND
100nF
VA+
(VDD)+5V
100 µF
+
100 nF
(GND) 0V
VDD
L = 47 µH R < 1Ω
GND
100nF
VB
L = 47 µH R < 1Ω
GND
100nF
RXVDD1
L = 47 µH R < 1Ω
GND
100nF
RXVDD2
TXGND
GND1
GND2
RXVDD1
RXVDD2
100 nF
RXVDD1
100 nF
RXVDD2
PLLVDD
VDD
VA+
100 nF
100 nF
VDD
TXVDD
IREF 62KΩ
XTO
XTI
1
1
1
XTAL COFFP
COFFN
ACS9020
RX
TXDATN
TXDATP
ENTX
TXVDD
LAP
PMN
LAN
TXMON
ACS9020
TX
50KΩ50KΩ
10 nF
10 nF RSET
VREF
10 nF
10 nF CTXBIAS
CTXMOD
TXGND
GND1
GND2
RMODSET
RBIASSET
RXVDD1 100 nF
RXVDD2
RXVDD2
100 nF
RXVDD1
100 nF
VDD
PLLVDD
VDD
VA+
100 nF
33
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 24: Diagram showing ACS9020 configuration for use with a 3-pin laser.
LEDRX = GND
PINRX = GND
XIN = GND
XOUT = float
F(2:0) = GND
RPLL = float
ENPLL = GND
DINP = GND
DINN = GND
DOUTP = float
DOUTN = float
IDOUT = GND
ICOFF = GND
CBTSTRP = GND
COFFWIN = float
ENCOFFB = GND
ENRXB = VDD
RXFLAG = float
RXMON = float
COFFP = float
COFFN = float
CAGC = float
COFFSET = float
VN = float
VP = float
PINN = float
PINP = float
MONN = float
BIASFIX = GND/VDD*
MODFIX = GND/VDD*
IBUF = GND
SDATAN = float
SDATAP = float
SCLKN = float
SCLKP = float
TXEN = float
TXSEL = GND
QUIETRX = GND
MONRX = GND
When employing a 4-pin Laser,
the MONN pin is connected to the
cathode of the laser's pin-monitor
diode
TXDATAN
TXDATAP
ENTX
TXVDD
LAP
MONP
LAN
TXFLAG
TXMON
Laser
Fiber
50KΩ50KΩ
10KΩ
10 nF
10 nF RSET
VREF
10 nF
10 nF CTXBIAS
CTXMOD
RXGND
TXGND
GND1
GND2
RMODSET
RBIASSET
RXVDD1 100 nF
RXVDD2
RXVDD2
100 nF
RXVDD1
100 nF
VDD
PLLVDD
VDD
VA+
100 nF
TXDATAN
TXDATAP
ENTX ACS9020
LEDRX = GND
PINRX = GND
XIN = GND
XOUT = float
F(2:0) = GND
RPLL = float
ENPLL = GND
DINP = GND
DINN = GND
DOUTP = float
DOUTN = float
IDOUT = GND
ICOFF = GND
CBTSTRP = GND
COFFWIN = float
ENCOFFB = GND
ENRXB = VDD
RXFLAG = float
RXMON = float
COFFP = float
COFFN = float
CAGC = float
COFFSET = float
VN = float
VP = float
PINN = float
PINP = float
MONN = float
MONP = float
BIASFIX = GND/VDD*
MODFIX = GND/VDD*
IBUF = GND
SDATAN = float
SDATAP = float
SCLKN = float
SCLKP = float
TXEN = float
TXSEL = GND
QUIETRX = GND
MONRX = GND
Figure 25: Diagram showing ACS9020 configuration for LED transmission.
TXDATAN
TXDATAP
ENTX
TXVDD
LAP
LAN
TXFLAG
TXMON
50KΩ50KΩ
10KΩ
10 nF
10 nF RSET
VREF
10 nF
10 nF CTXBIAS
CTXMOD
RXGND
TXGND
GND1
GND2
RMODSET
RBIASSET
RXVDD1 100 nF
RXVDD2
RXVDD2
100 nF
RXVDD1
100 nF
VDD
PLLVDD
VDD
VA+
100 nF
TXDATAN
TXDATAP
ENTX
LED
Fiber
ACS9020
* configure with a jumper to enable/disable automatic
bias power and modulation power regulation.
* configure with a jumper to enable/disable automatic
bias power and modulation power regulation.
Preliminary
34
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
LEDRX = GND
PINRX = VDD
XIN = GND
XOUT = float
F(2:0) = GND
RPLL = float
ENPLL = GND
DINP = GND
DINN = GND
ICOFF = GND
CBTSTRP = GND
COFFWIN = float
VN = float
VP = float
BIASFIX = VDD
MODFIX = VDD
IBUF = GND
SDATAN = float
SDATAP = float
SCLKN = float
SCLKP = float
TXEN = float
TXSEL = GND
QUIETRX = VDD
MONRX = GND
PMN = float
MONN = float
LAP = float
LAN = float
CTXMOD = float
CTXBIAS = float
RMODSET = float
RBIASSET = float
TXP = GND
TXN = GND
TXFLAG = float
TXMON = float
IDOUT = GND
Figure 26: Diagram showing ACS9020 configuration as a trans-impdeance-amplifier/post-amplifier.
LEDRX = GND
PINRX = GND
XIN = GND
XOUT = float
F(2:0) = GND
RPLL = float
ENPLL = GND
DINP = GND
DINN = GND
ICOFF = GND
CBTSTRP = GND
COFFWIN = float
PINN = float
PINP = float
BIASFIX = VDD
MODFIX = VDD
IBUF = GND
SDATAN = float
SDATAP = float
SCLKN = float
SCLKP = float
TXEN = float
TXSEL = GND
QUIETRX = VDD
MONRX = GND
PMN = float
MONN = float
LAP = float
LAN = float
CTXMOD = float
CTXBIAS = float
RMODSET = float
RBIASSET = float
TXP = GND
TXN = GND
TXFLAG = float
TXMON = float
IDOUT = GND
Figure 27: Diagram showing ACS9020 configuration as a post-amplifier.
Fiber
DOUTN
DOUTP
ENRXB
ENTX
ENCOFFB
PINP
PINN
RXMON
RXFLAG
PIN Diode
1MΩ
10 nF
CAGC
COFFSET
RSET
VREF
10 nF
10 nF
10 nF
1 nF
TXGND
GND1
GND2
RXGND
RXVDD1
RXVDD2
100 nF
RXVDD1
100 nF
RXVDD2
PLLVDD
VDD VA+
100 nF
100 nF
VDD
TXVDD
COFFP
COFFN
ACS9020
DOUTN
DOUTP
Fiber
DOUTN
DOUTP
ENRXB
ENTX
ENCOFFB
VP
VN
RXMON
RXFLAG
1MΩ
10 nF
CAGC
COFFSET
RSET
VREF
10 nF
10 nF
10 nF
1 nF
TXGND
GND1
GND2
RXGND
RXVDD1
RXVDD2
100 nF
RXVDD1
100 nF
RXVDD2
PLLVDD
VDD VA+
100 nF
100 nF
VDD
TXVDD
COFFP
COFFN
ACS9020
DOUTN
DOUTP
PIN Diode with
integrated TIA
CACoup
CACoup
CACoup = 1 nF
220Ω
220Ω
220Ω
220Ω
35
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
1 LEDRX
2 PINRX
3 XIN
4 XOUT
5F0
6F1
7F2
8 PLLVDD
9 GND2
10RPLL
11ENPLL
12DINP
13DINN
14DOUTP
15DOUTN
16IDOUT
17ICOFF
18CBTSTRP
19COFFWIN
20ENCOFFB
21ENRXB
22RXFLAG
23RXMON
24RXGND
25RXVDD1
26RXVDD2
27COFFP
28COFFN
29CAGC
30COFFSET
31RSET
32VREF
64 MONRX
63 QUIETRX
62 TXSEL
61 ENTX
60 TXEN
59 VDD
58 GND1
57 SCLKP
56 SCLKN
55 SDATAP
54 SDATAN
53 IBUF
52 TXMON
51 TXFLAG
50 TXN
49 TXP
48 MODFIX
47 BIASFIX
46 RBIASSET
45 RMODSET
44 CTXBIAS
43 CTXMOD
42 TXGND
41 LAN
40 LAP
39 TXVDD
38 MONN
37 PMN
36 PINP
35 PINN
34 VP
33 VN
Figure 28: Top view of 64 pin TQFP package.
RES = Reserved, IC = Internally Connected
ACAPELLA
ACS9020
2-Fiber Modem
Preliminary
36
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 29: Top view of 176 pin TQFP package.
RES = Reserved, IC = Internally Connected
1 TPOS7
2 TNEG7
3 RCLK6
4 RPOS6
5 GND
6 VD+
7 RNEG6
8 TCLK6
9 TPOS6
10 TNEG6
11 RCLK5
12 RPOS5
13 RNEG5
14 TCLK5
15 TPOS5
16 TNEG5
17 RCLK4
18 RPOS4
19 RNEG4
20 TCLK4
21 TPOS4
22 TNEG4
23 RCLK3
24 RPOS3
25 RNEG3
26 TCLK3
27 TPOS3
28 TNEG3
29 RCLK2
30 RPOS2
31 RNEG2
32 TCLK2
33 TPOS2
34 TNEG2
35 RCLK1
36 RNEG1
37 GND
38 VD+
39 RPOS1
40 TCLK1
41 TPOS1
42 TNEG1
43 RCLK10
44 RPOS10
45 RNEG10
46 TCLK10
47 TPOS10
48 TNEG10
49 RCLK11
50 RPOS11
51 GND
52 VD+
53 RNEG11
54 TCLK11
55 TPOS11
56 TNEG11
57 RCLK12
58 RPOS12
59 RNEG12
60 TCLK12
61 TPOS12
62 TNEG12
63 RCLK13
64 RPOS13
65 RNEG13
66 TCLK13
67 TPOS13
68 TNEG13
69 RCLK14
70 RPOS14
71 RNEG14
72 TCLK14
73 TPOS14
74 TNEG14
75 RCLK15
76 RPOS15
77 RNEG15
78 TCLK15
79 TPOS15
80 TNEG15
81 GND
82 VD+
83 TCLK16
84 GND
85 VD+
86 RCLK16
87 RPOS16
88 RNEG16
176 TCLK7
175 RNEG7
174 RPOS7
173 RCLK7
172 TNEG8
171 TPOS8
170 TCLK8
169 RNEG8
168 RPOS8
167 RCLK8
166 TNEG9
165 TPOS9
164 TCLK9
163 RNEG9
162 VD+
161 VD+
160 GND
159 GND
158 RPOS9
157 RCLK9
156 TmCLK
155 RmCLK
154 TPOS16
153 TNEG16
152 AD7
151 AD6
150 AD5
149 AD4
148 AD3
147 AD2
146 AD1
145 AD0
144 A4
143 A3
142 A2
141 A1
140 A0
139 VD+
138 GND
137 RDY
136 CSB
135 WRB
134 RDB
133 ALE
132 ENTX
131 DCD
130 GND
129 PORB
128 GND
127 UPSEL1
126 UPSEL2
125 UPSEL3
124 GND
123 GND
122 GND
121 XTO
120 XTI
119 DR1
118 DR2
117 DR3
116 RESEL
115 VA+
114 IREF
113 CM1
112 CM2
111 CM3
110 RXDATN
109 RXDATP
108 GND
107 TXDATN
106 TXDATP
105 VD+
104 TRSEL
103 CKC
102 CKM
101 MSEL1
100 MSEL2
99 MSEL3
98 ENRSB
97 CONTX
96 TmD2
95 TmD1
94 VD+
93 RmD2
92 RmD1
91 LOSS
90 ERRL
89 ERRC
1
ACAPELLA
ACS4110
2-Fiber Modem
37
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Pin Description ACS4110 part 1. Pin Description ACS4110 part 2.
Pin Sym IO Name Description
6,38,
52,82,
85,94,
105,139,
161,162
VD+ - +ve power
supply Power supply, 4.75 - 5.25
Volts.
115 VA+ - +ve power
supply
Power supply for Clock
Recovery PLL, 4.75 - 5.25
Volts.
5, 37,
51,81,
84,108,
122,123,
124,128,
130,138,
159,160
GN D - Gro und Po wer S upp ly
41
33
27
21
15
9
1
171
165
47
55
61
67
73
79
154
TPOS1
TPOS2
TPOS3
TPOS4
TPOS5
TPOS6
TPOS7
TPOS8
TPOS9
TPOS10
TPOS11
TPOS12
TPOS13
TPOS14
TPOS15
TPOS16
ITr a n s mit D a t a
Positive
Transmit channel 1- 16,
corresponds to +ve in bipolar
signal.
42
34
28
22
16
10
2
172
166
48
56
62
68
74
80
153
TNEG1
TNEG2
TNEG3
TNEG4
TNEG5
TNEG6
TNEG7
TNEG8
TNEG9
TNEG10
TNEG11
TNEG12
TNEG13
TNEG14
TNEG15
TNEG16
ITr a n s mit D a t a
Negative
Transmit channel 1- 16,
corresponds to -ve in bipolar
signal.
39
30
24
18
12
4
174
168
158
44
50
58
64
70
76
87
RPOS1
RPOS2
RPOS3
RPOS4
RPOS5
RPOS6
RPOS7
RPOS8
RPOS9
RPOS10
RPOS11
RPOS12
RPOS13
RPOS14
RPOS15
RPOS16
OReceive Data
Positive
Receive channel 1- 16,
corresponds to +ve in bipolar
signal.
Pin Sym IO Name Description
36
31
25
19
13
7
175
169
163
45
53
59
65
71
77
88
RNEG1
RNEG2
RNEG3
RNEG4
RNEG5
RNEG6
RNEG7
RNEG8
RNEG9
RNEG10
RNEG11
RNEG12
RNEG13
RNEG14
RNEG15
RNEG16
OReceive Data
Negative
Receive channel 1- 16,
corresponds to -ve in bipolar
signal.
131 DCD O Data C arrier
Detect
When DCD=1, then the
c o mmunica t ing mo d e ms ha ve
synchronised, and are
communicating.
120
121 XTI/
XTO -System C lock
Crystal
Co nnect fundamental parallel
resonance crystal with
appropriate padding capacitor
to GN D.
129 PORB I Power On
Reset
Will in it ia lis e t he de v ic e w h e n
PORB= 0. PORB is normally
connected to an RC circuit so
that a P OR is automatically
invoked on power-up. PORB=
1 for normal operation.
156 TmCLK I/O Transmit
maintenance
CLK
Tr a n s mit ma in t e nance Cloc k.
samples TmD on edge selected
b y TRS EL co ntr ol.
155 RmCLK O Receive
maintenance
Clock
Receive maintenance C lock.
samples RmD on edge selected
b y RES EL co ntr ol. .
116 RESEL I Receive Edge
Select
When RESEL = 1 ,
RPOS/RNEG and RmD data is
valid on the rising edge of
RC LK / RmC LK. W hen RESEL
= 0, the data is valid on the
falling edge of RCLK/RmCLK.
104 TRSEL I Tr a n s mit E d g e
Select
W he n TRS EL = 0,
TPOS/TNEG and TmD data is
latched on the falling edge of
TC LK / TmC LK . W hen TRSEL
=1, the data is latched on the
rising edge of TCLK/TmCLK.
95 TmD1 I Transmit
maintenance
Data
N RZ maintenance channel.
TmD is sampled on the
TmCLK clock edge defined by
TRSEL.
92 RmD2 O Receive
maintenance
Data
N RZ maintenance channel.
RmD is sampled on the
RmCLK clock edge defined by
RESEL.
Preliminary
38
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Pin Description ACS4110 part 3. Pin Description ACS4110 part 4.
Pin description ACS4110 part 5 - uP interface.
Pin Sym IO Name Description
40
32
26
20
14
8
176
170
164
46
54
60
66
72
78
83
TCLK1
TCLK2
TCLK3
TCLK4
TCLK5
TCLK6
TCLK7
TCLK8
TCLK9
TCLK10
TCLK11
TCLK12
TCLK13
TCLK14
TCLK15
TCLK16
I/O Transmit
clocks
Transmit Clock 1-16, samples
TPOS/TNEG data on clock
edge selected by input TRSEL.
35
29
23
17
11
3
173
167
157
43
49
57
63
69
75
86
RCLK1
RCLK2
RCLK3
RCLK4
RCLK5
RCLK6
RCLK7
RCLK8
RCLK9
RCLK10
RCLK11
RCLK12
RCLK13
RCLK14
RCLK15
RCLK16
O Receive clocks Receive C lock, RPO S/RN EG
data is valid on edge selected
by input RESEL.
113
112
111
CM1
CM2
CM3 IConfiguration
Modes
C M(3:1) se le ct the
Configuration Modes such as
full duplex, master and slave
mode.
90 ERRL O Error Latch
If errors are detected in the
8B10B coding rules ERRL will
b e fo rced h igh . . E R R L w ill be
reset low if the device is forced
out of synchronisation e.g.
P O RB = 0.
89 ERRC O Error c ount
E RR C w ill go hig h coincide n t
with each error detected in the
8B10B coding rules. Errors may
be accumulated by means of an
external electronic counter.
119
118
117
DR1
DR2
DR3 IData Ra te
Select
The DR(3:1) input select the
Data Rates and number of
channels. See section headed
Dat a Rat e Selection.
103 C KC I Clock Select
When CKC = 0, TCLK1-16
are configured as an output.
When CKC = 1, TCLK1-16
are configured as an input.
102 CK M I Clock Select
When CK M = 0, TmCLK is
configured as an output.
When CK M = 1, TmCLK is
configured as an input
97 CONTX I Continuous
transmit
114 IREF I Current
reference
A 51K Ω 1% resistor should be
placed between IREF and
GND.
Pin Sym IO Name Description
127
126
125
UPSEL1
UPSEL2
UPSEL3 I uP Interface uP interface mode control.
13 3 ALE I uP Interfa ce uP bus address latch enable.
1) POL3 in pin control mode
UP SEL(3:1) = 0.
13 4 RDB I uP Interfa ce uP bus read (active low).
2) POL2 in pin control mode
UP SEL(3:1) = 0.
135 WRB I uP Interface uP bus write (active low).
3) POL1 in pin control mode
UP SEL(3:1) = 0.
13 6 C SB IO uP Interfa ce uP b us chip select (active low).
4) CKLOCAL in pin control
modeUPSEL(3:1) = 0.
13 7 RDY O uP Interface uP b us r e ad y/ d a t a
acknowledge.
140
141
142
143
144
A0
A1
A2
A3
A4
IO uP Interfac e uP b us ad dress .
145
146
147
148
149
150
151
152
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
IO uP Interface uP bus address/data.
Pin Sym IO Name Description
91 LOSS O LO SS of
Signal
When LO SS = 1, receive data
is u nr eliab le.
When LO SS = 0, receive data
is r eliab le.
96 TmD1 I Transmit
maintenance
Data
N RZ maintenance channel.
TmD is sampled on the
TmCLK clock edge defined by
TRSEL.
93 RmD2 O Receive
maintenance
Data
N RZ maintenance channel.
RmD is sampled on the
RmCLK clock edge defined by
RESEL.
101
100
99
MSEL1
MSEL2
MSEL3 IMaintenance
channel data
rate selection
The MSEL(3:1) input select the
Data Rates of channels. See
section head ed Maintenance
Dat a Rat e Selection.
98 ENRSB I Enable
Remo te Se tup Remote de vice setup.
39
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Pin Description of interface signals between ACS9020 and ACS4110. Pin Description ACS9020 part 1.
Pin Sym IO Name Description
1 LEDRX I LED receive Set Logic High or Low.
2PINRXI
PINP/PINN
Receive Set Logic High or Low.
3
4XIN
XOUT -System Clock
Crystal External crystal with 20pF
padding capacitor.
5
6
7
F0
F1
F2 I Frequency set PLL rate select.
8 PLLVDD - VDD for
VCO Power supply, 4.75 - 5.25
Volts.
9 GN D2 - GN D Power supply.
10 RPLL - P LL reference
resistor 62KΩ to GN D
11 EN P LL I P LL Ena b le S e t Lo gic High o r Lo w.
12 DINP I P LL P o sit ive
input data C o nnec t to DO UTN .
13 DINN I P L L N e ga t ive
input data C o nnec t to DO UTP.
14 DOUTP O Receiver
P ositive output
data
Co nnect to DIN N (220Ω to
GND if IDOUT floating).
15 DOUTN O Receiver
Negative
output data
Connect to DINP (220Ω to
GND if IDOUT floating).
16 IDOUT - Reference
current for
Data outp ut
1KΩ to VDD (o r flo at if using
external differential o/p loads).
17 ICOFF -
Bias current
fo r auto matic
offset
compensation
windowing
100KΩ to RXVDD1 to give
COFFWIN delay of 60ns.
18 CBTSTRP -
A ut o offset
compensation
bootstrap
capacitor
10nF to GND to give 2ms
bootstrap delay (ICO FF =
100KΩ).
19 COFFWIN OAuto outp ut
generated
window output
Co nnect to EN CO FFB for auto
windowing.
20 ENCOFFB IReceiver offset
compensation
enable
Connect o COFFWIN for auto
windowing.
21 ENRXB I Receiver
enable S e t t o Lo gic High o r L o w.
22 RXFLAG O Receiver signal
mo n it o r flag Use to drive external monitor
LED.
23 RXMON - Receiver signal
monitor 1MΩ potentiometer to GND to
ad just RXF LAG thr eshold.
2 4 RXGN D - Gr ound P owe r supp ly.
25 RXVDD1 - Receive power
supply Power supply, 4.75 - 5.25
Volts.
Pin Sym IO Name Description
132
61 ENTX O
IEnable
Transmit Transmit active (ACS411 0).
Enable transmit (ACS9020).
110 RXDATN I Receive data N egative differential receive
d at a in ( o r slic in g lev e l in fo r
RXDATP).
109 RXDATP I Receive data Po sitive receive data in.
107 TXDATN O Transmit data Ne g a t iv e diff e r e n t ia l t r ans mit
d at a in ( o r slic in g lev e l in fo r
TXDATP).
10 6 TXDATP O Trans mit data P ositive transmit da ta o ut.
Preliminary
40
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Pin Description ACS9020 part 3.Pin Description ACS9020 part 2.
Pin Sym IO Name Description
49 TXP I Data transmit
positive Positive output of TX data
source.
50 TXN I Data transmit
negative Negative output of TX data
source.
51 TXFLAG O Transmit
current
mo n it o r flag
Used to drive external indicator
LED.
52 TXMON - Transmit
monitor
current
10KΩ potentiometer to GND
to a djust TXF LAG threshold.
53 IBUF -
Current
refere nce fo r
SDATA and
SCLK drivers
470Ω resistor to VDD (or float
if using external differential o/p
loads.
54 SDATAN O Re-synchronis-
e d ne ga tive
data
Re -s ync hro nis e d ne gat ive d a t a
output (120Ω to GN D if I BUF
floating).
55 SDATAP O Re-synchronis-
e d p os it iv e
data
Re- synchronised positive data
output (120Ω to GN D if I BUF
floating).
56 SCLKN O PLL
recovered
c lo c k ne ga t ive
P LL re c o ve r e d clo c k ne ga tive
(120Ω to GN D if I BUF
floating).
57 SCLKP O PLL
recovered
clock positive
PLL recovered clock positive
(120Ω to GN D if I BUF
floating).
5 8 GN D1 - Gr ound P owe r supp ly.
59 VDD - P ower supply Power supply, 4.75 - 5.25
Volts.
60 TXEN O Logic transmit
window enable C o nne c t to EN TX if us ing
internal packet data generator.
61 ENTX I Enable
transmit Set Logic High or Low or to
TXEN.
62 TXSEL I Select packet
transmit Set Logic High or Low.
63 QUIETRX IQuiet
reception Set Logic High or Low.
64 MONRX IMonitor PIN
receive select Set Logic High or Low.
Pin Sym IO Name Description
26 RXVDD2 - Pre-amp
power supply Power supply, 4.75 - 5.25
Volts.
27 COFFP - Post amp
offset
capacitor 1nF to COFFN .
28 COFFN - Post amp
offset
capacitor 1nF to COFFP.
29 CAGC - P reamp AGC
capacitor 1 0 nF to GN D.
30 COFFSET -P reamp offset
capacitor 1 0 nF to GN D.
31 RSET - Receiver
current bias
resistor 10 nF to GN D.
32 VREF - Bandgap
reference 10 nF to GN D.
33 VN - Postamp
ne ga tive inp ut Negative output from external
TIA.
34 VP - Postamp
p os it iv e input Positive output from external
TIA.
35 PINN - Receiver PIN
cathode La se r/ LED P IN c a tho d e.
36 PINP - Receiver P IN
anode La se r/ LED P IN a no de .
37 PMN - Mo nito r P IN
anode Laser monitor PIN anode.
38 MONN - Monitor PIN
cathode Laser monitor PIN cathode.
3 9 TXVDD - P o wer S upp ly Power supply, 4.75 - 5.25
Volts.
40
41 LAP
LAN -Anode
Cathode Las e r/LED ano d e.
La se r/ LED c at ho d e .
4 2 TXGN D - Gr ound P owe r supp ly.
43 CTXMOD -Laser/LED
modulation
La se r/ LED mo d ula tio n cur re nt
set smoothing capacitor 10nF to
GND.
44 CTXBIAS -Laser/LED
bias
Laser/LED bias current set
smoothing capacitor 10nF to
GND.
45 RMODSET -Laser/LED
modulation
La se r/ LED mo d ula tio n cur re nt
set resisto r 5 0K Ω
potentiometer to GND.
46 RBIASSET -Laser/LED
bias
Laser/LED bias current set
resistor 50KΩ potentiometer to
GND.
47 BIASFIX ILaser/LED
bias fix S e t Lo gic H igh o r Lo w.
48 MODFIX ILaser/LED
modulation
current fix S e t Lo gic High o r Low.
41
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 30: Block diagram for ACS4110.
txdat
p
txdatn
rxdatn REC
PLL 8B10B
DEC
S2P
RX AND LOCK
CONTROL
P2S 8B10B
CODER
TX CONTROL
RX
FIFO
P2S LINE
CODER
PLL
r
p
os1
rne
g
1
rclk1
r
p
os16
rne
g
16
rclk16
16x
TX
FIFO
S2P LINE
DEC
t
p
os1
tne
g
1
tclk1
S2P LINE
DEC
t
p
os16
tne
g
16
tclk16
16x
uP / MEMORY
INTERFACE MODE CONTROL /
STATUS
DATA
SLICER
xti xto
XTAL
OSC
MULT
PLL CLOCK + RESET
GENERATION
rmd1
rmd2
rmclk
P2S LINE
CODER
PLL
P2S
PLL
S2P
tmd1
tmd2
tmclk
ad<7:0> csb ale wrb rdb rd
y
u
p
sel<2:1
>
rxdat
p
entx
iref
p
orb
dcd errl
DIFF.
DRIVER
a<3:0> loss err
c
Preliminary
42
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Figure 31: Package information for the 64 and 176 pin TQFP packages.
Thin Quad Fla t Pa c k
di mensi o ns i n mm E1/D1 A A1 A2 e b L αE/D Copl.
min
T
Q
FP64
max
14.00
1.60
0.05
0.15
1.35
1.45
0.80
0.30
0.45
0.45
0.75
0o
7o
16.00
0.10
min
T
Q
FP176
max
24.00
1.60
0.05
0.15
1.35
1.45
0.50
0.17
0.27
0.45
0.75
0o
7o
26.00
0.10
43
Preliminary
ACS411CS PRE-RELEASE Issue 6.0 July 1999.
Acapella - a wholly owned subsidiary of
Acapella Ltd.
Delta House
Chilworth Research Centre
Southampton S016 7NS
United Kingdom
UK Tel. 023 80 769 008
UK Fax. 023 80 768 612
Intn'l. Tel. +44 23 80 769 008
Intn'l. Fax. +44 23 80 768 612
Email: sales@acapella.co.uk
Web: www.acapella.co.uk
This is a pre-released version of the specification. Since the specification is likely to
change in response to customer feedback, please check with Acapella that you have
the latest version of the specification.
In the interest of further product development Acapella reserve the right to change this specification without further notice.
© Copyright, Acapella Ltd. 1999
