DP83955AV National Semiconductor, DP83955AV Datasheet - Page 37

• Manufacturer Part Number: DP83955AV
• Description: IC CTRLR RIC REPEATER 100-PQFP
• Manufacturer: National Semiconductor
• Series: LERIC™r

Specifications of DP83955AV

• Controller Type: LitE Repeater Interface Controller
• Voltage - Supply: 5V
• Current - Supply: 250mA
• Mounting Type: Surface Mount
• Package / Case: 84-LCC (J-Lead)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Operating Temperature: -
• Interface: -
• Other names: *DP83955AV

6 0 Port Block Functions
6 2 SEGMENT PARTITION
Each of the LERIC ports has a dedicated state machine to
perform the functions defined by the IEEE partition algo-
rithm as shown in Figure 6-3 To allow users to customize
this algorithm for different applications a number of user
selected options are available during device configuration at
power up (the MLOAD cycle)
Two options are provided
1 The value of consecutive counts required to partition a
2 The operation of the ports’ state machines when recon-
segment (the CCLimit specification) may be set at either
31 or 63 consecutive collisions
necting a segment may also be modified by the user The
Transmit Only TXONLY configuration bit allows the user
to prevent segment reconnection unless the reconnect-
ing packet is being sourced by the repeater In this case
the repeater is transmitting on to the segment rather than
the segment transmitting when the repeater is idle The
normal mode of reconnection does not differentiate be-
(Continued)
37
6 3 PORT STATUS AND CONFIGURATION
REGISTER FUNCTIONS
Each LERIC port has its own status and configuration regis-
ter In addition to providing status concerning the port and
its network segment the register allows the following opera-
tions to be performed upon the port
1 Port disable When a port is disabled packet transmis-
2 Selection between normal and reduced squelch levels
tween such packets The TXONLY configuration bit is
input on pin D(5) during the MLOAD cycle If this option is
selected the operation of the state machine branch
marked (3) in Figure 6-3 is affected
In addition to the autonomous operation of the partition
state machines the user may reset these state ma-
chines This may be done individually to each port by
writing a logic one to the PART bit in its status register
The port’s partition state machine and associated coun-
ters are reset and the port is reconnected to the network
sion and reception between the port’s segment and the
rest of the network is prevented