DP83953VUL National Semiconductor, DP83953VUL Datasheet - Page 37

• Manufacturer Part Number: DP83953VUL
• Description: IC CTRLR RIC REPEATER 160-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83953VUL

• Controller Type: Ethernet Repeater Interface Controller
• Interface: IEEE 802.3
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 870mA
• 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: *DP83953VUL

5.0 HUB MANAGEMENT SUPPORT
Short Event reception (SE): This flag goes active if the
received packet is less than 74 bits long and no collision
occurs during reception.
5.3 Management Interface Operation
The Hub Management interface provides a mechanism to
combine repeater status information with packet informa-
tion to form a hub management packet. A serial bus inter-
face consisting of carrier sense, receive clock and receive
data is designed to connect one or more RIC2A's over a
backplane bus to another device, such as the DP83932
“SONIC
RIC2As form a powerful entity for network statistics gather-
ing.
The management interface consists of four pins:
The first three signals will emulate the interface between an
Ethernet controller and a phase locked loop decoder (such
as the DP83932 SONIC and the DP83910 SNI). These sig-
nals are driven by the RIC2A that receives the packet. The
MRXC and MRXD are comprised of a NRZ serial data
stream compatible with the DP83932. The PCOMP signal
is driven by logic circuitry on the processor board. The
actual data stream transferred as MRXD is derived from
the transferred data (IRD) on the Inter-RIC bus. The differ-
ence between these two data streams are:
1. At the end of packet repetition a hub management status
2. While the data of the repeated packet is being trans-
PCOMP
MRXC
MCRS
MRXD
field is appended to the data stream. This status field,
consisting of 7 bytes, is shown in Table 6, and Figure 14.
The information is obtained from several packet status
registers, which are described below. In accordance with
the IEEE Specification the least significant bit of a byte is
transmitted first.
ferred over the management bus, the received clock sig-
nals on the MRXC pin may be inhibited. This is controlled
by the Packet Compress pin PCOMP. If PCOMP is as-
serted during repetition of the packet then MRXC signals
are inhibited when the number of bytes (after SFD) trans-
ferred over the management bus equals the number dis-
played in the Packet Compress Decode Register. This
register provides a means to delay the effect of the
PCOMP signal, which may be generated early in the
packet's repetition. The packet compression feature re-
duces the amount of memory required to buffer packets
as they are received and are waiting to be processed by
hub management software. In this application, an ad-
dress decoder, which forms part of the packet compress
logic, would monitor the address fields as they are re-
ceived over the management bus. If the destination ad-
TM
” controller. The SONIC combined with the
Management Receive Clock - 10MHz NRZ
Clock output.
Management Carrier Sense - Input/ Output
indicating of valid data stream.
Management Receive Data - NRZ Data output
synchronous to MRXC
Packet Compress - Input to truncate the
packet's data field.
(Continued)
37
Note: If
bytes defined by the packet compression register, then packet compression
will not occur.
The Management Interface may be fine tuned to meet the
timing considerations of the SONIC and the access time of
its associated packet memory. This refinement may be per-
formed in two ways:
1. The default mode of operation of the Management inter-
2. The Management bus has been designed to accommo-
The status field, shown in Table 6, contains information of
six different types. They are contained in seven Packet Sta-
tus Registers "PSRs":
1. The RIC2A and port address fields [PSR(0) and (1)] can
dress is not the address of the management node inside
the hub, then packet compression could be employed. In
this manner only the portion of the packet meaningful for
hub management interrogation (i.e., the address fields,)
is transferred to the SONIC and buffered into memory.
If the repeated packet ends before PCOMP is asserted
or before the required number of bytes have been trans-
ferred, then the hub management status field is directly
appended to the received data at a byte boundary. If the
repeated packet is significantly longer than the value in
the Decode Register requires, and PCOMP is asserted,
the status fields will be delayed until the end of packet
repetition. During this delay period MRXC clocks are in-
hibited, but the MCRS signal remains asserted.
face is to only transfer packets over the bus which have
a start of frame delimiter. Thus "packets" that are only
preamble/jam and do not convey any source or destina-
tion address information are inhibited. This filtering may
be disabled by writing a logic zero to the Management In-
terface Configuration or "MIFCON" bit in the Manage-
ment
Section 7.0 for details.
date situations of maximum network utilization, for exam-
ple, when collision generated fragments occur. (These
collision fragments may violate the IEEE 802.3 IFG
specification.) The IFG required by the SONIC is a func-
tion of the time taken to release space in the receive
FIFO and to perform end of packet processing (write sta-
tus information into memory). These functions are prima-
rily memory operations and consequently depend upon
bus latency and the memory access time of the system.
In order to allow the system designer some discretion in
choosing the speed of this memory, the RIC2A may be
configured to protect the SONIC from a potential FIFO
overflow condition. This is performed by utilizing the In-
terFrame Gap (IFG) Threshold Select Register.
The value (plus one) held in this register defines the min-
imum allowable InterFrame Gap on the management
bus, measured in network bit times. If the gap is smaller
than this number, MCRS is asserted but MXRC clocks
are inhibited. Consequently, no data is transferred. So,
the system designer may decide whether or not to gather
statistics or to monitor a subset on all packets, even
though they only occur with very small IFGs.
uniquely identify the repeater port receiving the packet
out of a potential maximum of 832 ports sharing the
same management bus (64 RIC2As each with 13 ports).
PCOMP
and
is asserted late in the packet, i.e., after the number of
Interrupt
Configuration
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Register.
See