726

Fibre Channel GBaud Optical
Link Module

Technical Data

HGLM-1063

Features

ˇ ANSI X3.230-1994 Fibre

Channel Standard
Compatible (FC-0)

ˇ FCSI-301-Rev 1.0 "GBaud

Link Module Specification"
Compatible

ˇ Standard 20 Bit (1063 MBd),

TTL Interface

ˇ Class I Laser Safety

Certified

ˇ Single +5.0 V Power Supply

Applications

ˇ Mass Storage System I/O

Channel

ˇ Computer System I/O

Channel

ˇ High Speed Peripheral

Interface

Description

The HGLM-1063 Gigabaud
Optical Link Module, provides a
complete Fibre Channel FC-0
layer solution. The module meets
the requirements of the 100-M5-
SL-I physical link as defined by
the American National Standards
Institute (ANSI) X3.230-1994
Fibre Channel standard. The
HGLM-1063 is also compatible
with the Fibre Channel Systems
Initiative (FCSI) document
#FCSI-301-Rev 1.0 "Gigabaud

Optical Link Module"
specification.

The HGLM-1063 transmits and
receives 8b/10b encoded,
parallel, data in the 20 bit wide
format defined by the FCSI-301
document. The 20 bit wide data is
transmitted at 100MB/sec over a
serial fiber link and has the
capability to receive data at
100 MB/sec simultaneously. With
overhead, this translates to a
serial line rate of 1062.5 MBaud
transmitting and 1062.5 MBaud
receiving. The serial data link
uses a 780 nm laser transmitter
and photodiode. The optimum
fiber is 50/125

m multimode

fiber (62.5/125

m multimode

fiber can be used with degraded
performance) and attaches to the
HGLM-1063 via a duplex SC
connector.

As specified in the Fibre Channel
Standard, the HGLM-1063 is a
Class 1 laser safe device; the
transmitted optical signal shuts
down in the case of an open fiber
condition after a specific time
interval. The HGLM-1063
accomplishes this by monitoring
the transmitted optical power
levels, and the received optical
signal.

The HGLM-1063 is intended for
use in building adapter cards (or
equivalent devices) as shown in
Figure 1. The HGLM-1063 pro-
vides complete FC-0 functionality.
The HPFC-5000 provides the
FC-1 through FC-4 functions and
interfaces directly to the HGLM-
1063. Finally, a bus gasket is
used to connect the HPFC-5000
to the specific system bus in use.
This block diagram is meant only
to illustrate the basic Fibre
Channel functionality.

For proper operation, it is
necessary to connect the HGLM-
1063 to another HGLM-1063 (or
equivalent) in a full duplex
configuration as depicted in
Figure 3. This ensures proper
operation of the Open Fiber
Control circuitry and allows
proper link startup and
synchronization.

5964-6638E (4/96)

727

FIBER

HGLM-1063

GIGABAUD OPTICAL

LINK MODULE

BUS GASKET

SYSTEM BUS

HPFC-5000

TACHYON

Figure 1. Example System Adapter Card, Block Diagram (Simplified).

Functional Description

A simplified block diagram of the
HGLM-1063 module is shown in
Figure 2. This block diagram
shows the 5 key elements of the
module. These are the Transmit-
ter I.C., the Laser Diode Assembly,
the Receiver I.C., the photodiode
assembly, and the Open Fiber
Control circuit. The high level of
integration on the HGLM-1063 is
apparent from this block
diagram. Pin assignments and
signal definitions are given on
pages 6 and 7.

In general, the HGLM-1063
utilizes a user provided Transmit
Byte Clock (TBC) of 53.125 MHz
to transmit two 8b/10b encoded
data bytes, simultaneously, by
creating a serial data stream of
1062.5 MBd and modulating a
780 nm laser diode with it. The
20 bit wide (two encoded bytes)
data input is provided to the
module through the 80 pin con-
nector in standard TTL format.
Similarly, the HGLM-1063
receives 780 nm optical signals at
a data rate of 1062.5 MBd,
deserializes this data stream to
recover the two encoded data

bytes and provides this 20 bit
wide standard TTL data to the
receiving system via the 80 pin
connector. The receiver also
recovers the byte rate clock for
use in clocking the received 20
bit wide parallel data.

Link Acquisition and
Power Up

The following discussion assumes
the HGLM-1063 is connected in a
full duplex point to point link as
shown in Figure 3. When initially
applying power to the HGLM-
1063, the Transmit Byte Clock
must start no later than 5 msec
after the +5 volt supply reaches
the +4 volt level. If this require-
ment is not met, the Open Fiber
Control (OFC) circuit may stick
in a nonfunctional state. If this
should happen, the OFC can be
put into a functional state by
holding the Enable Wrap
(EWRAP) line high for 10.5
seconds. Once the TBC is
running, and the module is
properly powered up, the follow-
ing sequence should be followed
to bring the link into full

synchronization and ready to
transmit data:

1. Both Link Unusable lines will
be driven high, by the OFC,
indicating neither receiver is
detecting a signal from the link.

2. Drive the Transmit Data lines,
Tx[00:19] to a
01010101010101010101.

3. Drive the input control lines as
follows:
ˇ Enable Wrap: low
ˇ Tx_SI: low
ˇ Enable Comma Detect: high
ˇ -Lock to Reference: high

4. Assuming the link is properly
connected, and both link ends are
in the same state of readiness, the
lasers will turn on in 10.1
seconds. This will be indicated by
the Link Unusable lines going
low. This transition indicates the
OFC is operational and in
control.

5. Once the lasers have come on,
and Link Unusable is observed to
transition low, bring -Lock to
Reference low for at least
500

sec. This forces the module

to frequency lock to the Transmit
Byte Clock.

728

Figure 2. HGLM-1063 Functional Block Diagram.

CLOCK (TBC)

ENCODED DATA

CLOCK (RBC[0:1])

ENCODED DATA

CLOCK (RBC[0:1])

ENCODED DATA

CLOCK (TBC)

ENCODED DATA

HGLM1

HGLM2

FIBER PATH A

FIBER PATH B

Figure 3. Full Duplex Point to Point Link.

HDMP-1512

TRANSMITTER

I.C.

DATA BYTE 1

Tx[10:19]

DATA BYTE 0

Tx[00:09]

LASER DIODE

ASSEMBLY

DATA BYTE 0
Rx[00:09]

OPEN FIBER

CONTROL

I.C.

TBC

ą SERIAL DATA IN

PHOTODIODE

ASSEMBLY

EWRAP

Tx_SI

HDMP-1514

RECEIVER

I.C.

FIBER INPUT

LOL A, B

EN_CDET

-LCK_REF

DATA BYTE 1
Rx[10:19]

COM_DET

RBC[0:1]

L_UNUSE

FAULT

ą SERIAL DATA OUT

FIBER OUTPUT

FAULT

-LZON

Figure 4. Typical HGLM-1063 Label.

HGLM-1063

780 nm GLM Module

CDRH21 CFR(J) Compilant

Class 1 Laser Product

09 Nov. 1995 San Jose, CA

Made in U.S.A. from domestic

and foreign components.

729

6. After holding -Lock to
Reference low for 500

sec it

should then be driven high. This
causes the module to phase and
frequency lock onto the incoming
data stream within 2500 bit times
(2.4

sec).

7. After 2500 bit times, the
modules should be in bit syn-
chronization, but not yet byte
synchronization. The Receive
Byte Clock (RBC0) should be
running at 53.125 MHz.

8. Finally, drive the data lines
Tx[00:19] with a K28.5 (comma
or byte sync) character. Upon
detection of this character, the
receiver will drive the Comma
Detect line high, the clocks will
align to the byte boundary, and
the receive data lines (Rx[00:19])
will have valid data. The link is
now ready for data transmission.

TX_SI Operation

In normal operation, pin Tx_SI
should be held low. In this mode,
the data at Tx[00:19] is serialized
and driven over the fiber optic
link. With pin Tx_SI driven high,
however, the data at Tx[00:19] is
serialized and driven out the

Serial Data Out lines and the

data applied to the

Serial Data

In lines are driven over the fiber
optic link.

EWRAP Operation

To aid in link diagnostics, the
modules have the capability of
wrapping the local transmit data
electrically back to the local
deserializer. This feature is
enabled by driving the EWRAP
pin high. When enabled, EWRAP
causes the laser to turn off within
20

sec. The OFC circuit goes

into its low duty cycle "on-off-on"
handshake mode. The link will
need to be stepped through the
synchronization procedure

outlined above to return to
normal operation after EWRAP is
brought low.

Enable Comma Detect

In the synchronization procedure
above, the Enable Comma Detect
(EN_CDET) signal is driven high
to allow the receiver to reset and
align its boundaries properly
when a K28.5 character is
transmitted. This line can be kept
in a high state and the receiver
will reset on every K28.5
character it detects. This feature
can be disabled, after initial
synchronization, by driving
Enable Comma Detect to a low
state.

Open Fiber Control

The purpose of the Open Fiber
Control (OFC) integrated circuit
is to ensure user safety. This
circuit uses the dual loss of light
signals from the receiver I.C. and
the laser Fault detection signal
from the transmitter I.C. to
determine if the laser and the
fiber link are properly connected
and functioning normally. Should
a Fault condition be determined,
all laser transmission is shut
down.

A safety interlock is provided by
the HGLM-1063 module. HGLM-
1063 modules (or equivalent)
must be connected in full point-
to-point configuration as shown
in Figure 3 for proper operation.
The Open Fiber Control System
(OFCS) of the HGLM-1063
deactivates the laser signal
whenever there is an interruption
or loss of signal of either laser
drive circuit.

For example, in Figure 3, if Path
A is opened through a cut or
other physical damage to the
fiber, or if the fiber is discon-

nected at either the transmitting
port of HGLM1 or the receiving
port of HGLM2, the OFCS detects
the loss of signal. The Link
Unusable line of HGLM2 goes
high, signaling the system of an
open fiber condition. The OFCS
then shuts down the laser of
HGLM2. HGLM1 in turn detects
this loss of signal, raises its Link
Unusable line, and shuts down its
laser. The OFC pulses the laser of
HGLM2 at a very low duty cycle.
Simultaneously, the OFCS of
HGLM1 detects the low duty
cycle operation of HGLM2 and
places its laser in the same low
duty cycle pulsing mode. It takes
less than 2 msec to shut down all
laser transmission and results in a
safe (Class I) laser emission level
in Path A, the open path.

While Path A is still open,
HGLM1 launches a pulse
synchronously with the pulse it
receives on Path B from HGLM2.
However, HGLM2 receives no
pulse (because Path A is open)
and continues in an inactive
mode. HGLM2 will continue
launching "inquiry" pulses once
approximately every 10.1 seconds
along Path B.

After Path A is restored, HGLM2
will receive pulses along Path A,
synchronous with its transmit
pulses along Path B. A completed
link of Path A and Path B is
verified by both HGLM1 and
HGLM2. HGLM2 will verify its
link by deactivating its laser and
confirm that its receive signal
disappears. HGLM1 also
performs the same verification
check, deactivating its laser.
Once both HGLM modules have

730

deactivated their lasers, HGLM2
then activates its laser, sends a
signal to HGLM1 (which activates
its laser), which in turn sends a
confirming signal back to
HGLM2. This on-off-on handshake
confirms that the first syn-
chronous pulse came from
another HGLM-1063, or
equivalent module, with an OFC
safety system. Once this
sequence is complete, the link
between HGLM1 and HGLM2
returns to normal operation, with
both in the active mode. The on-
off-on timing is compatible with
the timing requirements of the
ANSI FC-PH specification for
Open Fibre Control timing of
100-M5-SL-I links. These timings
are defined as Decode 1, 2, and 3
and are given in the Timing
Specifications table later in this
document.

Laser Safety Compliance

The HGLM-1063 is designed and
certified as a Class 1 laser

product per 21 CFR (U.S. Code
of Federal Regulations),
Subchapter J. A Class 1 laser
product is safe for use and does
not pose a biological hazard if
used in accordance within the
data sheet limits and instructions.

CAUTION:

There are no user serviceable
parts nor any maintenance
required for the HGLM-1063.
All adjustments are made at
the factory before shipment to
our customers. Tampering
with, modifying or breaking
the preset trim pot seals will
result in voided product
warranty. It may also result in
improper operation of the
HGLM-1063 circuitry, and
possible overstress of the
laser source. Device degrada-
tion or product failure may
result.

Connection of the HGLM-1063
to a non-approved optical
source, operating above the
recommended absolute maxi-
mum conditions (especially
power supply) or operating
the HGLM-1063 in a manner
inconsistent with its design
and function may result in
hazardous radiation exposure
and may be considered an act
of modifying or manufacturing
a laser product. The person(s)
performing such an act is
required by law to recertify
and reidentify the laser
product under the provisions
of 21 CFR(Subchapter J).

Labeling

Each HGLM-1063 module is
labeled per 21 CFR
(Subchapter J), including the
actual date of manufacture
(Figure 4).

Figure 5. HGLM-1063 Outline Drawing.

3.5

(0.138)

30.8

(1.213)

37.8

(1.488)

5.0

(0.197)

(2X)

1.25

(0.049)

11.0

(0.433)

11.5

(0.453)

24.13

(0.950)

35.25

(1.388)

74.27 (2.924)

63.53 (2.501)

28.35 (1.116)

27.0 (1.063)

4.8 (0.189)

2.5 mm DIAMOND PIN

2.0

(0.079)

(2X)

RECEIVER

TRANSMITTER

25.4

(1.000)

2.0

(0.079)

28.0

(1.102)

30.0

(1.181)

2.5

(0.098)

PIN

BOTTOM VIEW

DIMENSIONS IN MILLIMETERS (INCHES).

Part Number HGLM-1063

Document Outline