AM7969-175JC AMD (ADVANCED MICRO DEVICES), AM7969-175JC Datasheet - Page 78

• Manufacturer Part Number: AM7969-175JC
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM7969-175JC

• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Package Type: PLCC
• Mounting: Surface Mount
• Pin Count: 28
• Lead Free Status / Rohs Status: Not Compliant

Figure 6-5
74
AMD
Fiber Optic Data Link Decoupling
7.0 CASCADE MODE OPERATION
The TAXIchip set can be cascaded to send multiple byte words over a single serial
channel. Cascade operation is the loading of n bytes of data into a TAXI Transmitter,
and the serial transmission of that data through the Transmitter to the media. Data and
Command bytes are multiplexed into the Local Mode transmitter. Detailed block diagram
and explanation of the data multiplexing method are described in section 7.1. Also see
Appendix C, TAXI TIP #14.
For Am7969-125 TAXI Receivers, the connection is parallel for data and daisy-chained
for control. That is, the SERIN pins of all TAXI receivers are connected together and to
the media. The daisy chain of IGM to CNB control signals determines which Receiver
latches which incoming byte. The Receiver whose CNB input is connected to +5 V is the
primary Receiver, supplying the initial IGM, as well as a reference frequency for the X1
inputs of the down stream TAXI receivers.
Cascade mode does not increase data rate or throughput. The maximum data rate is
100 Mbits per second, cascaded
that the width of the data word is transparently maintained. If the application requires the
transfer of 32 bits of data, Cascade mode allows TAXI transmitters to latch all the data,
and send it over a single serial channel, and receive the data in proper order in four
TAXI receivers at the other end of the link.
Another advantage of cascade mode is that if a byte gets corrupted, the system can be
reset by just sending a Sync, ensuring that the first TAXI Receiver gets the first byte, the
second Receiver gets the second byte, and so on. Performing this reset operation with
latches would require additional logic to decode a Sync command which in turn would
reset all the latches.
For Am7969-175 TAXI Receivers, see Appendix C TAXI TIP #13 for single receiver
cascade operation.
(1)
Note:
Actually, in Non Auto-Repeat Cascade Mode, the throughput is less than 100 Mbits/s due to the need to
send Syncs.
Power Supply
Ground
This connection includes a ferrite bead in the V
FODL
V
Plane
TAXIchip Integrated Circuits Technical Manual
CC
0.1 F
4.7 F
0.1 F
As Appropriate
As Appropriate
FODL GND Plane
Logic V
4.7 F
(2)
or not. The advantage of cascading lies in the fact
CC
Plane
CC
Ferrite Bead (Part# 2743002111 by Fair-Rite)
circuit of the fiber optic components.
Logic GND Plane
4.7 F
.1 F
TAXI V
As Appropriate
TAXI GND Plane
TAXI GND Plane
CC
Plane
12330E-22