DP83256VF-AP NSC [National Semiconductor], DP83256VF-AP Datasheet - Page 18

• Manufacturer Part Number: DP83256VF-AP
• Manufacturer: NSC [National Semiconductor]

3 0 Functional Description
3 4 CONFIGURATION SWITCH
The Configuration Switch consists of a set of multiplexers
and latches which allow the PLAYER
the data paths without any external logic The Configuration
Switch is controlled through the Configuration Register
(CR)
The Configuration Switch has four internal buses the
A Request bus the B Request bus the Receive bus and
the PHY Invalid bus The two Request buses can be driv-
en by external input data connected to the external PHY
Port interface The Receive bus is internally connected to
the Receive Block of the PLAYER
PHY Invalid bus has a fixed 10-bit SMT PHY Invalid con-
nection (LSU) pattern (1 0011 1010) which is useful during
the connection process
The configuration switch also has three internal multiplex-
ers each can select any of the four buses to connect to its
FIGURE 3-8 Configuration Switch
Block Diagram for DP83257
a
a
device to configure
device while the
(Continued)
TL F 11708–11
18
respective data path The first two are PHY Port interface
output data paths A Indicate and B Indicate that can
drive output data paths of the external PHY Port interface
The third output data path is connected internally to the
Transmit Block
The Configuration Switch is the same on the DP83256 de-
vice the DP83256-AP device and the DP83257 device
However the DP83257 has two PHY Port interfaces con-
nected to the Configuration Switch whereas the DP83256
and DP83256-AP have one set of PHY port interfaces The
DP83257 uses the A Request and A Indicate paths as
one PHY Port interface and the B Request and B Indi-
cate paths as the other PHY Port interface (See Figure 3-8 )
The DP83256 and DP83256-AP having one port interface
use the B Request and A Indicate paths as its external
port
DP83256 and DP83256-AP are null connections and are not
used by the device (See Figure 3-9 )
The A Request and B Indicate paths of the
FIGURE 3-9 Configuration Switch
Block Diagram for DP83256
and DP83256-AP
TL F 11708 – 12