dp83251 National Semiconductor Corporation, dp83251 Datasheet - Page 12

• Manufacturer Part Number: dp83251
• Description: Player Device Fddi Physical Layer Controller
• Manufacturer: National Semiconductor Corporation

3 0 Functional Description
STATION CONFIGURATIONS
Single Attach Station (SAS)
The Single Attach Station can be connected to either the
Primary or Secondary ring via a Concentrator Only 1 MAC
is needed in a SAS
Both the DP83251 and DP83255 can be used in a Single
Attach Station The DP83251 can be connected to the MAC
via its only PHY Port Interface The DP83255 can be con-
nected to the MAC via either of the 2 PHY Port Interfaces
See Figures 3-6 and 3-7
Dual Attach Station (DAS)
A Dual Attach Station can be connected directly to the dual
ring There are two types of Dual Attach Stations DAS with
a Single MAC and DAS with Dual MACs See Figures 3-8
and 3-9
FIGURE 3-6 Single Attach Station Using the DP83251
FIGURE 3-8 Dual Attachment Station (DAS) Single MAC
FIGURE 3-9 Dual Attachment Station (DAS) Dual MACs
(Continued)
TL F 10386 – 8
12
Although two DP83251s can be connected together to build
a Dual Attach Station it is recommended that the DP83255
is to be used for this type of station configuration
A DAS with Single MAC can be configured as follows
The DAS with Dual MACs can be configured as follows





B Indicate data of PHY A is connected to A Request
input of PHY B B Request input of PHY A is con-
nected to A Indicate output of PHY B
The MAC can be connected to either the A Request
input and the A Indicate output of PHY A or the
B Request
of PHY B
B Indicate data of PHY A is connected to A Request
input of PHY B B Request input of PHY A is con-
nected to A Indicate output of PHY B
The MAC 1 is connected to the B Indicate output and
the B Request Input of PHY B
The MAC 2 is connected to the A Indicate output and
the A Request Input of PHY A
FIGURE 3-7 Single Attachment Station (SAS)
input
Using the DP83255
and
the
B Indicate
TL F 10386 – 10
TL F 10386 – 11
TL F 10386 – 9
output