DP83950BVQB National Semiconductor, DP83950BVQB Datasheet - Page 26

• Manufacturer Part Number: DP83950BVQB
• Description: IC CTRLR RIC REPEATER 160-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83950BVQB

• Controller Type: Ethernet Repeater Interface Controller
• Interface: IEEE 802.3
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 380mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-MQFP, 160-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83950BVQB

5 1 and it performs the majority of the data and collision
5 0 Functional Description
Port State Machine (PSM)
There are two primary functions for the PSM as follows
1 Control the transmission of repeated data and jam sig-
2 Decide whether a port will be the source of data or colli-
Main State Machine (MSM)
The MSM controls the operation of the shared functional
blocks in each RIC as shown in the block diagram Figure
propagation operations as defined by the IEEE specifica-
tion these include
Regeneration
Enforcement
Enforcement
Enforcement
SION state a further arbitration operation is performed to
nals over the attached segment
sion information which will be repeated over the network
This repeater port is known as PORT N An arbitration
process is required to enable the repeater to transition
from the IDLE state to the SEND PREAMBLE PATTERN
or RECEIVE COLLISION states see Figure 5 3 This pro-
cess is used to locate the port which will be PORT N for
that particular packet The data received from this port is
directed to the PLL decoder and transmitted over the In-
ter-RIC bus If the repeater enters the TRANSMIT COLLI-
determine which port is PORT M PORT M is differentiat-
ed from the repeater’s other ports if the repeater enters
the ONE PORT LEFT state In this state PORT M does
not transmit to its segment where as all other ports are
still required to transmit to their segments
Generation
Extension
Function
Preamble
Fragment
Preamble
Encoding
Elasticity
Transmit
Collision
Control
Pattern
Control
Buffer
Jam
Data
Tw1
Tw2
Restore the length of the preamble
pattern to the defined size
Extend received data or collision
fragments to meet the minimum
fragment length of 96 bits
A portion of the received packet may
require storage in an Elasticity Buffer to
accommodate preamble regeneration
In cases of receive or transmit collisions
a RIC is required to transmit a jam
pattern (1010
Note This pattern is the same as that used for
preamble regeneration
Once the TRANSMIT COLLISION state
is entered a repeater is required to stay
in this state for at least 96 network bit
times
NRZ format data from the elasticity
buffer must be encoded into Manchester
format data prior to retransmission
Enforce the Transmit Recovery Time
specification
Enforce Carrier Recovery Time
specification on all ports with active
collisions
Action
)
(Continued)
26
The interaction of the main and port state machines is visi-
ble in part by observing the Inter-RIC bus
Inter-RIC Bus Operation
Overview
The Inter-RIC Bus consists of eight signals These signals
implement a protocol which may be used to connect multi-
ple RICs together In this configuration the logical function
of a single repeater is maintained The resulting multi-RIC
system is compliant to the IEEE 802 3 repeater specification
and may connect several hundred network segments An
example of a multi-RIC system is shown in Figure 5 4
The Inter-RIC Bus connects multiple RICs to realize the fol-
lowing operations
The following tables briefly describes the operation of each
bus signal the conditions required for a RIC to assert a
signal and which RICs (in a multi-RIC system) would monitor
a signal
RIC Receiving
RIC Receiving
required for a
required for a
Port N Identification (which port the repeater receives
Port M Identification (which port is the last one experienc-
RECEIVE COLLISION identification
TRANSMIT COLLISION identification
DISABLE OUTPUT (jabber protection)
data from)
ing a collision)
Data Transfer
RIC to drive
RIC to drive
Conditions
Conditions
this signal
this signal
the Signal
the signal
Function
Function
PORT M may be identified by its ACKO
Input signal to the PSM arbitration
chain This chain is employed to
identify PORT N and PORT M
Note A RIC which contains PORT N or
signal being low when its ACKI input is
high
Not applicable
This is dependent upon the method
used to cascade RICs described in
a following section
Output signal from the PSM
arbitration chain
This is dependent upon the method
used to cascade RICs described in
a following section
Not applicable
ACKO
ACKI