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参数资料
| 型号： | M7020R-066ZA1T |
| 厂商： | 意法半导体 |
| 英文描述： | 32K x 68-bit Entry NETWORK SEARCH ENGINE |
| 中文描述： | 32K的× 68位进入网络搜索引擎 |
| 文件页数： | 118/150页 |
| 文件大小： | 996K |
| 代理商： | M7020R-066ZA1T |
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M7020R
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LEARN COMMAND
Bit [0] of each 68-bit data location specifies wheth-
er an entry in the database is occupied. If all the
entries in a device are occupied, the device as-
serts FULO signal to inform the downstream de-
vices that it is full.
The result of this communication between depth-
cascaded devices determines the global FULL
signal for the entire table. The FULL signal in the
last device determines the fullness of the depth-
cascaded table.
In a depth-cascaded table, only a single device will
learn the entry through the application of a LEARN
Instruction. The determination of which device is
going to learn is based on the FULI and FULO sig-
nalling between the devices. The first non-full de-
vice learns the entry by storing the contents of the
specified comparand registers to the location(s)
pointed to by NFA.
In a x68-configured table the LEARN command
writes a single 68-bit location. In a x136-config-
ured table the LEARN command writes the next
even and odd 68-bit locations. In 136-bit mode,
Bit[0] of the even and odd 68-bit locations is ’0,’
which indicates they are cascaded empty, or ’1,’
which indicates they are occupied.
The global FULL signal indicates to the Table Con-
troller (the host ASIC) that all entries within a block
are occupied and that no more entries can be
learned. The M7020R updates the signal after
each WRITE or LEARN command to a data array.
The LEARN command generates a WRITE cycle
to the external SRAM, also using the NFA register
as part of the SRAM address (see SRAM AD-
DRESSING, page 126).
The LEARN command is supported on a single
block containing up to eight devices if the table is
configured either as a x68 or a x136. The LEARN
command is not supported for x272-configured ta-
bles.
LEARN is a pipelined operation and lasts for two
CLK cycles, as shown in Figure 87, page 119
where TLSZ = 00, and Figure 88, page 120 and
Figure 89, page 121 where TLSZ = 01 (which as-
sume the device performing the LEARN operation
is not the last device in the table and has its LRAM
Bit set to ’0.’
Note:
The OE_L for the device with the LRAM Bit
set goes high for two cycles for each LEARN (one
during the SRAM WRITE cycle, and one the cycle
before). The latency of the SRAM WRITE cycle
from the second cycle of the Instruction is shown
in Table 49, page 121.
The sequence of operation is as follows:
–
Cycle 1A
: The host ASIC applies the LEARN In-
struction on the CMD[1:0], using CMDV = 1.
The CMD[5:2] field specifies the index of the
comparand register pair that will be written in
the data array in the 136-bit-configured table.
For a LEARN in a 68-bit-configured table, the
even-numbered comparands specified by this
index will be written. CMD[8:7] carries the bits
that will be driven on SADR[21:20] in the SRAM
WRITE cycle.
–
Cycle 1B
: The host ASIC continues to drive
CMDV to '1,' CMD[1:0] to '11,' and CMD[5:2]
with the comparand pair index. CMD[6] must be
set to '0' if the LEARN is being performed on a
68-bit-configured table, and to '1' if the LEARN
is being performed on a 136-bit-configured ta-
ble.
–
Cycle 2:
The host ASIC drives the CMDV to '0.'
At the end of Cycle 2, a new instruction can be-
gin. The latency of the SRAM WRITE is the
same as the search to the SRAM READ Cycle.
It is measured from the second cycle of the
LEARN Instruction.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| M7020R-083ZA1T | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:32K x 68-bit Entry NETWORK SEARCH ENGINE |
| M702-230442 | 功能描述:火线接头 IEEE 1394 SMT 4P HORIZONTAL RoHS:否 制造商:Molex 产品:IEEE 1394 Firewire Connectors 标准:IEEE 1394 位置/触点数量:6 节距:2 mm 触点电镀:Unplated 触点材料:Phosphor Bronze 型式:Female 电流额定值:0.5 A 安装风格:Through Hole 端接类型:Solder Tab 连接器类型:Firewire Receptacle |
| M702-230642 | 功能描述:火线接头 IEEE 1394 SMT 6P HORIZONTAL RoHS:否 制造商:Molex 产品:IEEE 1394 Firewire Connectors 标准:IEEE 1394 位置/触点数量:6 节距:2 mm 触点电镀:Unplated 触点材料:Phosphor Bronze 型式:Female 电流额定值:0.5 A 安装风格:Through Hole 端接类型:Solder Tab 连接器类型:Firewire Receptacle |
| M7023 | 制造商:Tamura Corporation of America 功能描述: |
| M7027 | 功能描述:数字万用表 Dual Display Multime 0.3% Accuracy RoHS:否 制造商:Tektronix 产品:Multimeters 类型:Bench 准确性:0.04 % 电压范围:2 V to 2 kV 电阻范围: 电容范围: 显示计数: 频率:10 Hz to 45 Hz, 850 Hz to 1 MHz 测距: 真均方根值: 数据保持: |
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