DP83850CVF National Semiconductor, DP83850CVF Datasheet - Page 12

• Manufacturer Part Number: DP83850CVF
• Description: IC CONTROLLER INTERFACE 132-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83850CVF

• Controller Type: Ethernet Repeater Interface Controller
• Interface: Serial
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 295mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 132-MQFP, 132-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83850CVF

3.0 Functional Description
3.9 Management Bus
The task of network statistics gathering in a repeater sys-
tem is divided between the DP83850C and DP83856
devices. Together, these devices collect all the required
management information (compliant to IEEE 802.3u clause
30) associated with a packet.
Each time a packet is received by a DP83850C, it drives
the device and the port number onto the management bus
in 3 contiguous nibbles of data.
During a single reception, only one DP83850C drives this
information onto the management bus. During a collision,
the management bus will TRI-STATE (because the infor-
mation on this bus becomes invalid).
The first nibble of management data contains the least sig-
nificant 4 bits of the RID number, the second contains the
most significant bit of the RID number and the third con-
tains the number of the receiving port.
When the 100RIC is not receiving a packet, it monitors the
RID numbers from other 100RICs. If there is a match
between any of these numbers and 100RIC’s own RID,
then a RID contention error signal (RID_ER) is asserted.
The management bus also indicates whether an elasticity
buffer error (due to under-run or over-run) has occurred by
asserting the /M_ER signal.
3.10 Management Event Flags and Counters
Repeater management statistics are supported either
directly by using the DP83850C's on-chip event flags and
counters, or indirectly, by the DP83850C providing the
information to the DP83856 via the management and
transmit bus.
Management
DP83850C in two ways: event flags and counters.
Activity on the 100RIC
with RID=00010
Activity on the 100RIC
with RID=00011
/IR_Vect value on
Activity on the 100RIC
with RID=00011
Activity on the 100RIC
with RID=00010
/IR_VECT value on
the backplane
the backplane
information
is
maintained
(Continued)
Figure 2. RID to /IR_VECT Mapping
00010
00011
within
RID=00010
RID=00011
the
12
3.10.1 Event Flags
These are the events that provide a snapshot of the opera-
tion of the DP83850C. These events include:
3.10.2 Event Counters
The event counters maintain the statistics for events that
occur too frequently for polled flags, or are collision ori-
ented. Each port has its own set of event counters that
keep track of the following events:
3.11 Serial Register Interface
The DP83850C has 64 registers held in two pages of 32
(Register Page 0 and Register Page 1). The registers are
16 bits wide. Only one page of registers can be accessed
at a time.
After power-up and/or reset, the DP83850C defaults to
Register Page 0. Register Page 1 can be accessed by writ-
ing 0001h to the PAGE register in Register Page 0, where-
upon further accesses will be to Register Page 1.
Collision
Collision
Auto-Partition State, indicating whether a port is current-
ly partitioned.
Jabber State, indicating whether a port is in jabber state.
Administration State, indicating if a port is disabled.
Port Collisions. A 32-bit counter providing the number of
collision occurrences on a port.
Port Partitions. A 16-bit counter indicating the number of
times that the port has partitioned.
Late Events. A 32-bit counter indicating the number of
times that a collision took place after 512 bit times (nom-
inal). In the case of late events, both the late event and
the collision counters will be incremented.
Short Events. A 32-bits wide counter indicating the num-
ber of packets whose length is 76 bits (nominal) or less.
00010
00010
RID=00011
RID=00010
One port left
One port left
00011
00010
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