- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄45179 > MB86965A 2 CHANNEL(S), 10M bps, LOCAL AREA NETWORK CONTROLLER, PQFP16 PDF資料下載
參數(shù)資料
| 型號： | MB86965A |
| 元件分類： | 微控制器/微處理器 |
| 英文描述： | 2 CHANNEL(S), 10M bps, LOCAL AREA NETWORK CONTROLLER, PQFP16 |
| 封裝： | PLASTIC, QFP-160 |
| 文件頁數(shù)： | 27/76頁 |
| 文件大?。?/td> | 394K |
| 代理商： | MB86965A |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁當前第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁
MB86965
33
NODE ID REGISTERS
The Node ID Registers are accessed in register bank “0”
at register addresses xxx8H - xxxDH. During node
initialization, the unique Ethernet address assigned to the
node loads into these registers. The first register at xxx8H
corresponds to the first byte of the Node ID, or the first
address byte to be received as a packet arrives from the
network. If EtherCoupler is configured to do so via
Address Filter bits, DLCR5<1:0>, the destination
address field of an incoming packet compares with the
Node ID stored in these registers. The packet is accepted,
if it passes the error filter and there is a match.
The Node ID registers are readable and writable registers,
and should not be accessed while the Receiver is enabled.
To avoid interaction with the Receiver, access the Node
ID registers only when DLC EN, DLCR6<7>, is 1. It is
recommended that the Node ID registers be written and
read only during initialization before enabling the
Receiver, i.e., before writing 0 to DLC EN. The address
contained in the Node ID registers is used only for receive
(destination) address filtering, not for the source address
of outgoing packets. The system provides outgoing
packet addresses as part of the packet data. Within each
byte, bits are transmitted and received on the network in a
least-significant-bit-first order.
Time Domain Reflectometry (TDR) Counter
The TDR Counter approximately indicates the location
of a fault on the network, if one exists. When a node
transmits, a short or open on the network causes a
reflected signal to the node receiver, which can
sometimes be detected. The reflection causes failure of
the carrier sense or detection of a false collision. Time
domain reflectometry allows estimates of the distance
along the network cable from the node to the fault.
The TDR Counter counts the number of transmitted bits
before occurrence of a collision or loss of carrier sense,
whichever comes first. If neither occurs during packet
transmission, the count clears. The elapsed time
represents twice the signal delay from node to fault. An
open on the network may cause a false collision, whereas
a short usually causes loss of carrier sense. The TDR
Count comes from DLCR14 (the least-significant byte)
and DLCR15 (the most-significant byte). Only the lower
14 bits of the counter are equipped, which is more than is
needed for an IEEE or Ethernet LAN. The top two bits,
DLCR15<7:6>, are always 0.
To perform the TDR fault test, first enable interrupts for
TX DONE, by setting DLCR2<7> high. An alternative to
use the interrupt is to poll the TX DONE bit, looking for a
high level. Set the 16 Collisions register, BMPR11, to
07H for this test (no halt, skip-failed packet). Clear status
bits by writing FF86H to the Receive and Transmit Status
registers. Next, try to transmit a packet length of 600 or
more bits. Up to 16 attempts may be made automatically,
if collisions are indicated. Upon completion of the
transmission attempts, TX Done goes high, generating
an interrupt, if enabled. When this occurs, read the
Transmit Status register and the TDR register.
Interpreting The Results
If the count is zero, no fault was detected. If the count is
greater than zero, but smaller than the packet length, a
cable fault my exist. If the count is less than 525, a real
collision may have occurred during test. Real collisions
normally occur within the first 65 bytes of the packet,
including preamble. Note the error messages, COL and
CR LOST. COL high suggests a cable open, whereas CR
LOST suggests a short. Repeat the measurement several
times, throw out any anomalous values, and average the
rest. A cluster of readings at about the same value is a
strong indicator of a valid fault measurement. If such a
cluster of readings occurs, multiply the average of the
cluster by 39 feet to estimate the distance from the node to
the fault. [39 feet = (100 ns x 0.8 x 186,282 miles/second
x 5280 feet/mile)/2; this assumes the network is mostly
coaxial cable with signal propagation speed of
approximately 0.8 x C, the speed of light.]
HASH TABLE
The Hash Table provides a way to filter incoming
multicast packets so the host processor need not process
packets that are not of interest. The principal behind this
filtering process is based on the arrangement of a large
number of elements of an array, or database, to facilitate
searching for elements associated with a given key or
datum. The hash function is a mathematical or logical
function that maps all elements in a domain onto a smaller
domain called the hash table.
Assume this hashing function as an example: treat the
multicast address as a nonnegative 48-bit integer, divide
this number by 64 and take the remainder. This function
maps all multicast addresses into a 64-element hash table
because the remainder must be integer values 0 through
63. Applying this hashing function results in taking the
least-significant six bits of the multicast address as an
integer. In the hash table, for each element, 0 through 63, a
single bit is stored to indicate if the address is accepted (1)
or rejected (0). If, for example, the node belongs to three
multicast groups, only three or fewer of the hash table
elements store ones, and the rest store zeroes. The scheme
相關PDF資料 |
PDF描述 |
|---|---|
| MB88151APNF-G-500-JNE1 | OTHER CLOCK GENERATOR, PDSO8 |
| MB88151APNF-G-401-JNEFE1 | OTHER CLOCK GENERATOR, PDSO8 |
| MB88151APNF-G-801-JNERE1 | OTHER CLOCK GENERATOR, PDSO8 |
| MB88151APNF-G-400-JNERE1 | OTHER CLOCK GENERATOR, PDSO8 |
| MB88151APNF-G-200-JNEFE1 | OTHER CLOCK GENERATOR, PDSO8 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MB86965B | 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:EtherCoupler ETHERNET CONTROLLER WITH 10BASE?T TRANSCEIVER |
| MB86965BPF-G-BND | 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:EtherCoupler ETHERNET CONTROLLER WITH 10BASE?T TRANSCEIVER |
| MB86967 | 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:LAN Controller with PC Card, ISA Bus, and General-purpose Bus Interfaces |
| MB86967PFV | 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:LAN Controller with PC Card, ISA Bus, and General-purpose Bus Interfaces |
| MB86977 | 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:IP PACKET FORWARDING ENGINE |
發(fā)布緊急采購，3分鐘左右您將得到回復。