DP83256VF National Semiconductor, DP83256VF Datasheet - Page 21

• Manufacturer Part Number: DP83256VF
• Description: IC FDDI LAYER CTRLR 160PQFP
• Manufacturer: National Semiconductor
• Series: PLAYER+™r

Specifications of DP83256VF

• Controller Type: physical layer controller
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-BFQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Supply: -
• Interface: -
• Other names: *DP83256VF

3 0 Functional Description
CONCENTRATOR CONFIGURATIONS
There are 2 types of concentrators Single Attach and Dual
Attach These concentrators can be designed with or with-
out MAC(s) The configuration is determined based upon its
type and the number of active MACs in the concentrator
Using the PLAYER
with many different configurations without any external log-
ic
The DP83256 DP83256-AP and DP83257 can be used to
build a Single Attach concentrator
See Application Note AN-675 Designing FDDI concentra-
tors and Application Note AN-741 Differentiating FDDI con-
centrators for further information
Concepts
A concentrator is comprised of 2 parts the Dual Ring Con-
nect portion and the Master Ports
The Dual Ring Connection portion connects the concentra-
tor to the dual ring directly or to another concentrator If the
concentrator is connected directly to the dual ring it is a
part of the ‘‘Dual Ring of Trees’’ If the concentrator is con-
nected to another concentrator it is a ‘‘Branch’’ of the
‘‘Dual Ring of Trees’’
The Master Ports connect the concentrator to its ‘‘Slaves’’
or S-class Single Attach connections A slave could be a
Single Attach Station or another concentrator (thus forming
another Branch of the Dual Ring Tree)
When a MAC in a concentrator is connected to the primary
or secondary ring it is required to be situated at the exit port
of that ring (i e its PH IND is connected to the IND Inter-
face of the last Master Port in the concentrator (PHY M n)
that is connected to that ring)
A concentrator can have two MACs one connected to the
primary ring and one to the secondary ring In addition rov-
ing MACs can be included in the concentrator configuration
A roving MAC can be used to test the stations connected to
the concentrator before allowing them to join the dual ring
a
device a concentrator can be built
(Continued)
21
Figure 3-15 shows a Single Attach concentrator with a sin-
Figure 3-16 shows a Dual Attach concentrator with a single
Figure 3-17 shows a Dual Attach concentrator with dual
This may require external multiplexers if used in conjunc-
tion with two other MAC layers
Single Attach Concentrator
A Single Attach concentrator is a concentrator that has only
one PHY at the dual ring connect side It cannot therefore
be connected directly to the dual ring A Single Attach con-
centrator is a branch to the dual ring tree It is connected to
the ring as a slave of another concentrator
Multiple Single Attach concentrators can be connected to-
gether hierarchically to build a multiple levels of branches in
a dual ring
The Single Attach concentrator can be connected to either
the primary or secondary ring depending on the connection
with its concentrator (the concentrator that it is connected
to as a slave)
gle MAC
Dual Attach Concentrator
A Dual Attach concentrator is a concentrator that has two
PHYs on the dual ring connect side It is connected directly
to the dual ring and is a part of the dual ring tree
The Dual Attach concentrator is connected to both the pri-
mary and secondary rings
Dual Attach Concentrator with Single MAC
MAC
Because the concentrator has one MAC it can only transmit
and receive frames on the ring to which the MAC is con-
nected The concentrator can only repeat frames on the
other ring
Dual Attach Concentrator with Dual MACs
MACs
Because the concentrator has two MACs it can transmit
and receive frames on both the primary and secondary
rings