欢迎访问ic37.com |
会员登录 免费注册
发布采购

LAN8700IC-AEZG 参数 Datasheet PDF下载

LAN8700IC-AEZG图片预览
型号: LAN8700IC-AEZG
PDF下载: 下载PDF文件 查看货源
内容描述: [LAN Controller, 4 Channel(s), 12.5MBps, CMOS, 6 X 6 MM, 0.90 MM HEIGHT, ROHS COMPLIANT, QFN-36]
分类和应用: 通信时钟局域网数据传输外围集成电路
文件页数/大小: 83 页 / 687 K
品牌: SMSC [ SMSC CORPORATION ]
 浏览型号LAN8700IC-AEZG的Datasheet PDF文件第25页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第26页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第27页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第28页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第30页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第31页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第32页浏览型号LAN8700IC-AEZG的Datasheet PDF文件第33页  
±15kV ESD Protected MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support and flexPWR® Technology in a Small Footprint  
Datasheet  
4.7  
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.  
Once auto-negotiation has completed, information about the resolved link can be passed back to the  
controller via the Serial Management Interface (SMI). The results of the negotiation process are  
reflected in the Speed Indication bits in register 31, as well as the Link Partner Ability Register  
(Register 5).  
The auto-negotiation protocol is a purely physical layer activity and proceeds independently of the MAC  
controller.  
The advertised capabilities of the PHY are stored in register 4 of the SMI registers. The default  
advertised by the PHY is determined by user-defined on-chip signal options.  
The following blocks are activated during an Auto-negotiation session:  
„
„
„
„
„
„
„
Auto-negotiation (digital)  
100M ADC (analog)  
100M PLL (analog)  
100M equalizer/BLW/clock recovery (DSP)  
10M SQUELCH (analog)  
10M PLL (analog)  
10M Transmitter (analog)  
When enabled, auto-negotiation is started by the occurrence of one of the following events:  
„
„
„
„
„
Hardware reset  
Software reset  
Power-down reset  
Link status down  
Setting register 0, bit 9 high (auto-negotiation restart)  
On detection of one of these events, the PHY begins auto-negotiation by transmitting bursts of Fast  
Link Pulses (FLP). These are bursts of link pulses from the 10M transmitter. They are shaped as  
Normal Link Pulses and can pass uncorrupted down CAT-3 or CAT-5 cable. A Fast Link Pulse Burst  
consists of up to 33 pulses. The 17 odd-numbered pulses, which are always present, frame the FLP  
burst. The 16 even-numbered pulses, which may be present or absent, contain the data word being  
transmitted. Presence of a data pulse represents a “1”, while absence represents a “0”.  
The data transmitted by an FLP burst is known as a “Link Code Word.” These are defined fully in IEEE  
802.3 clause 28. In summary, the PHY advertises 802.3 compliance in its selector field (the first 5 bits  
of the Link Code Word). It advertises its technology ability according to the bits set in register 4 of the  
SMI registers.  
There are 4 possible matches of the technology abilities. In the order of priority these are:  
„
„
„
„
100M Full Duplex (Highest priority)  
100M Half Duplex  
10M Full Duplex  
10M Half Duplex  
SMSC LAN8700/LAN8700i  
Revision 2.3 (04-12-11)  
DATA2S9HEET