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LAN9217_07 参数 Datasheet PDF下载

LAN9217_07图片预览
型号: LAN9217_07
PDF下载: 下载PDF文件 查看货源
内容描述: 16位高性能单芯片10/100以太网控制器与HP Auto-MDIX的 [16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX]
分类和应用: 控制器以太网局域网(LAN)标准
文件页数/大小: 137 页 / 1566 K
品牌: SMSC [ SMSC CORPORATION ]
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16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX  
Datasheet  
clock. This is used to Manchester encode the NRZ data stream. When no data is being transmitted  
(TX_EN is low), the TX10M block outputs Normal Link Pulses (NLPs) to maintain communications with  
the remote link partner.  
4.4.3  
10M Transmit Drivers  
The Manchester encoded data is sent to the analog transmitter where it is shaped and filtered before  
being driven out as a differential signal across the TXP and TXN outputs.  
4.5  
10Base-T Receive  
The 10Base-T receiver gets the Manchester- encoded analog signal from the cable via the magnetics.  
It recovers the receive clock from the signal and uses this clock to recover the NRZI data stream. This  
10M serial data is converted to 4-bit data nibbles which are passed to the controller across the MII at  
a rate of 2.5MHz.  
This 10M receiver uses the following blocks:  
„
„
„
„
Filter and SQUELCH (analog)  
10M PLL (analog)  
RX 10M (digital)  
MII (digital)  
4.5.1  
4.5.2  
10M Receive Input and Squelch  
The Manchester signal from the cable is fed into the PHY (on inputs RXP and RXN) via 1:1 ratio  
magnetics. It is first filtered to reduce any out-of-band noise. It then passes through a SQUELCH  
circuit. The SQUELCH is a set of amplitude and timing comparators that normally reject differential  
voltage levels below 300mV and detect and recognize differential voltages above 585mV.  
Manchester Decoding  
The output of the SQUELCH goes to the RX10M block where it is validated as Manchester encoded  
data. The polarity of the signal is also checked. If the polarity is reversed (local RXP is connected to  
RXN of the remote partner and vice versa), then this is identified and corrected. The reversed condition  
is indicated by the flag “XPOL“, bit 4 in register 27. The 10M PLL is locked onto the received  
Manchester signal and from this, generates the received 20MHz clock. Using this clock, the  
Manchester encoded data is extracted and converted to a 10MHz NRZI data stream. It is then  
converted from serial to 4-bit wide parallel data.  
The RX10M block also detects valid 10Base-T IDLE signals - Normal Link Pulses (NLPs) - to maintain  
the link.  
4.5.3  
Jabber Detection  
Jabber is a condition in which a station transmits for a period of time longer than the maximum  
permissible packet length, usually due to a fault condition, that results in holding the TX_EN input for  
a long period. Special logic is used to detect the jabber state and abort the transmission to the line,  
within 45ms. Once TX_EN is deasserted, the logic resets the jabber condition.  
4.6  
Auto-negotiation  
The purpose of the Auto-negotiation function is to automatically configure the PHY to the optimum link  
parameters based on the capabilities of its link partner. Auto-negotiation is a mechanism for  
exchanging configuration information between two link-partners and automatically selecting the highest  
performance mode of operation supported by both sides. Auto-negotiation is fully defined in clause 28  
of the IEEE 802.3 specification.  
SMSC LAN9217  
65  
Revision 1.8 (06-06-07)  
DATASHEET