參數資料
型號: KSZ8895MQ-EVAL
廠商: Micrel Inc
文件頁數: 51/119頁
文件大小: 0K
描述: BOARD EVALUATION FOR KSZ8895MQ
標準包裝: 1
主要目的: 接口,以太網控制器(PHY 和 MAC)
嵌入式:
已用 IC / 零件: KSZ8895MQ
已供物品:
相關產品: 576-3753-ND - IC ETHERNET SW 5PORT 128-PQFP
其它名稱: 576-3871
Micrel, Inc.
KSZ8895MQ/RQ/FMQ
The KSZ8895MQ/RQ/FMQ will not forward the following packets:
1.
Error packets
These include framing errors, Frame Check Sequence (FCS) errors, alignment errors, and illegal size packet
errors.
2.
IEEE802.3x PAUSE frames
KSZ8895MQ/RQ/FMQ intercepts these packets and performs full duplex flow control accordingly.
3.
"Local" packets
Based on destination address (DA) lookup, if the destination port from the lookup table matches the port from
which the packet originated, the packet is defined as "local."
Half-Duplex Back Pressure
The KSZ8895MQ/RQ/FMQ also provides a half-duplex back pressure option (note: this is not in IEEE 802.3
standards). The activation and deactivation conditions are the same as the ones given for full-duplex mode. If back
pressure is required, the KSZ8895MQ/RQ/FMQ sends preambles to defer the other station's transmission (carrier
sense deference). To avoid jabber and excessive deference as defined in IEEE 802.3 standards, after a certain
period of time, the KSZ8895MQ/RQ/FMQ discontinues carrier sense but raises it quickly after it drops packets to
inhibit other transmissions. This short silent time (no carrier sense) is to prevent other stations from sending out
packets and keeps other stations in a carrier sense-deferred state. If the port has packets to send during a back
pressure situation, the carrier sense-type back pressure is interrupted and those packets are transmitted instead. If
there are no more packets to send, carrier sense-type back pressure becomes active again until switch resources
are free. If a collision occurs, the binary exponential backoff algorithm is skipped and carrier sense is generated
immediately, reducing the chance of further colliding and maintaining carrier sense to prevent reception of packets.
To ensure no packet loss in 10BASE-T or 100BASE-TX half-duplex modes, the user must enable the following:
Aggressive backoff (Register 3, bit 0)
No excessive collision drop (Register 4, bit 3)
Back pressure (Register 4, bit 5)
These bits are not set as the default because this is not the IEEE standard.
Broadcast Storm Protection
The KSZ8895MQ/RQ/FMQ has an intelligent option to protect the switch system from receiving too many broadcast
packets. Broadcast packets are normally forwarded to all ports except the source port and thus use too many switch
resources (bandwidth and available space in transmit queues). The KSZ8895MQ/RQ/FMQ has the option to include
“multicast packets” for storm control. The broadcast storm rate parameters are programmed globally and can be
enabled or disabled on a per port basis. The rate is based on a 50ms (0.05s) interval for 100BT and a 500ms (0.5s)
interval for 10BT. At the beginning of each interval, the counter is cleared to zero and the rate limit mechanism starts
to count the number of bytes during the interval. The rate definition is described in Registers 6 and 7. The default
setting for Registers 6 and 7 is 0x4A (74 decimal). This is equal to a rate of 1%, calculated as follows:
148,80 frames/sec X 50ms (0.05s)/interval X 1% = 74 frames/interval (approx.) = 0x4A
March 12, 2014
37
Revision 1.7
相關PDF資料
PDF描述
202D285-3/42-0 BOOT MOLDED
0210391086 CABLE JUMPER 1MM .178M 37POS
202F221-50-0 BOOT MOLDED
222F274-51-0 BOOT MOLDED
202A196-25-0 BOOT MOLDED
相關代理商/技術參數
參數描述
KSZ8895MQI 功能描述:以太網 IC 5-Port 10/100 Ethernet Switch with 1x MII Interface (Industrial Grade) RoHS:否 制造商:Micrel 產品:Ethernet Switches 收發(fā)器數量:2 數據速率:10 Mb/s, 100 Mb/s 電源電壓-最大:1.25 V, 3.45 V 電源電壓-最小:1.15 V, 3.15 V 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-64 封裝:Tray
KSZ8895MQXCA 功能描述:Ethernet Switch 10/100 Base-T/TX I2C, SPI Interface 128-PQFP (14x20) 制造商:microchip technology 系列:- 包裝:托盤 零件狀態(tài):有效 協(xié)議:以太網 功能:開關 接口:I2C,SPI 標準:10/100 Base-T/TX 電壓 - 電源:1.8V,2.5V,3.3V 電流 - 電源:129mA 工作溫度:0°C ~ 70°C 封裝/外殼:128-BFQFP 供應商器件封裝:128-PQFP(14x20) 標準包裝:66
KSZ8895MQXIA 功能描述:Ethernet Switch 10/100 Base-T/TX I2C, SPI Interface 128-PQFP (14x20) 制造商:microchip technology 系列:- 包裝:托盤 零件狀態(tài):有效 協(xié)議:以太網 功能:開關 接口:I2C,SPI 標準:10/100 Base-T/TX 電壓 - 電源:1.8V,2.5V,3.3V 電流 - 電源:129mA 工作溫度:-40°C ~ 85°C 封裝/外殼:128-BFQFP 供應商器件封裝:128-PQFP(14x20) 標準包裝:66
KSZ8895RQ 功能描述:以太網 IC 5-port Switch, one SW5-RMII and one P5-RMII Interface RoHS:否 制造商:Micrel 產品:Ethernet Switches 收發(fā)器數量:2 數據速率:10 Mb/s, 100 Mb/s 電源電壓-最大:1.25 V, 3.45 V 電源電壓-最小:1.15 V, 3.15 V 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-64 封裝:Tray
KSZ8895RQ TR 功能描述:以太網 IC 5-port Switch, one SW5-RMII and one P5-RMII Interface RoHS:否 制造商:Micrel 產品:Ethernet Switches 收發(fā)器數量:2 數據速率:10 Mb/s, 100 Mb/s 電源電壓-最大:1.25 V, 3.45 V 電源電壓-最小:1.15 V, 3.15 V 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-64 封裝:Tray