Cable Diagnostics The KSZ8851-16" />
參數(shù)資料
型號(hào): KSZ8851-16MLL-EVAL
廠商: Micrel Inc
文件頁數(shù): 14/84頁
文件大小: 0K
描述: BOARD EVALUATION KSZ8851-16MLL
產(chǎn)品培訓(xùn)模塊: KSZ8851 10/100 Embedded Controllers
標(biāo)準(zhǔn)包裝: 1
系列: LinkMD®
主要目的: 接口,以太網(wǎng)控制器(PHY 和 MAC)
嵌入式:
已用 IC / 零件: KSZ8851-16MLL
主要屬性: 1 個(gè)端口,100BASE-TX/10BASE-T
次要屬性: 8/16 位接口,LinkMD 線纜診斷
已供物品: 板,文檔
產(chǎn)品目錄頁面: 1081 (CN2011-ZH PDF)
相關(guān)產(chǎn)品: 576-3438-ND - IC CTLR MAC/PHY NON PCI 128PQFP
576-3253-ND - IC CTLR MAC/PHY NON-PCI 128-PQFP
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其它名稱: 576-3292
Micrel, Inc.
KSZ8851-16MLL/MLLI
March 11, 2014
21
Revision 2.2
LinkMD
Cable Diagnostics
The KSZ8851-16MLL LinkMD
uses time domain reflectometry (TDR) to analyze the cabling plant for common cabling
problems such as open circuits, short circuits, and impedance mismatches.
LinkMD
works by sending a pulse of known amplitude and duration down the MDI and MDI-X pairs and then analyzes
the shape of the reflected signal. Timing the pulse duration gives an indication of the distance to the cabling fault with a
maximum distance of 200m and an accuracy of ±2m. Internal circuitry displays the TDR information in a user-readable
digital format in register P1SCLMD[8:0].
Note: cable diagnostics are only valid for copper connections – fiber-optic operation is not supported.
Access
LinkMD
is initiated by accessing register P1SCLMD, the PHY special control/status & LinkMD register (0xF4).
Usage
LinkMD
can be run at any time by ensuring that Auto-MDIX has been disabled. To disable Auto-MDIX, write a ‘1’ to
P1CR[10] to enable manual control over the pair used to transmit the LinkMD
pulse. The self-clearing cable diagnostic
test enable bit, P1SCLMD [12], is set to ‘1’ to start the test on this pair.
When bit P1SCLMD[12] returns to ‘0’, the test is complete. The test result is returned in bits P1SCLMD[14:13] and the
distance is returned in bits P1SCLMD[8:0]. The cable diagnostic test results are as follows:
00 = Valid test, normal condition
01 = Valid test, open circuit in cable
10 = Valid test, short circuit in cable
11 = Invalid test, LinkMD
failed
If P1SCLMD[14:13]=11, this indicates an invalid test, and occurs when the KSZ8851-16MLL is unable to shut down the
link partner. In this instance, the test is not run, as it is not possible for the KSZ8851-16MLL to determine if the detected
signal is a reflection of the signal generated or a signal from another source.
Cable distance can be approximated by the following formula:
P1SCLMD[8:0] x 0.4m for port 1 cable distance
This constant may be calibrated for different cabling conditions, including cables with a velocity of propagation that varies
significantly from the norm.
Media Access Control (MAC) Operation
The KSZ8851-16MLL strictly abides by IEEE 802.3 standards to maximize compatibility.
Inter Packet Gap (IPG)
If a frame is successfully transmitted, then the minimum 96-bit time for IPG is measured between two consecutive
packets. If the current packet is experiencing collisions, the minimum 96-bit time for IPG is measured from carrier sense
(CRS) to the next transmit packet.
Back-Off Algorithm
The KSZ8851-16MLL implements the IEEE standard 802.3 binary exponential back-off algorithm in half-duplex mode.
After 16 collisions, the packet is dropped.
Late Collision
If a transmit packet experiences collisions after 512 bit times of the transmission, the packet is dropped.
Flow Control
The KSZ8851-16MLL supports standard 802.3x flow control frames on both transmit and receive sides.
On the receive side, if the KSZ8851-16MLL receives a pause control frame, the KSZ8851-16MLL will not transmit the next
normal frame until the timer, specified in the pause control frame, expires. If another pause frame is received before the
current timer expires, the timer will be updated with the new value in the second pause frame. During this period (while it
is flow controlled), only flow control packets from the KSZ8851-16MLL are transmitted.
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參數(shù)描述
KSZ8851-16MLL-EVAL 制造商:Micrel Inc 功能描述:BOARD EVALUATION FOR KSZ8851-16MLL
KSZ8851-16MLLI 功能描述:以太網(wǎng) IC 10/100BT Ethernet MAC + PHY with Generic (8, 16-bit) Bus Interface (I-Temp, Lead Free) RoHS:否 制造商:Micrel 產(chǎn)品:Ethernet Switches 收發(fā)器數(shù)量:2 數(shù)據(jù)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
KSZ8851-16MLLI TR 功能描述:以太網(wǎng) IC 10/100BT Ethernet MAC + PHY with Generic (8, 16-bit) Bus Interface (I-Temp, Lead Free) RoHS:否 制造商:Micrel 產(chǎn)品:Ethernet Switches 收發(fā)器數(shù)量:2 數(shù)據(jù)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
KSZ8851-16MLLJ 功能描述:以太網(wǎng) IC Single-Port Ethernet MAC Controller with 8/16-Bit Non-PCI Interface (125C support) RoHS:否 制造商:Micrel 產(chǎn)品:Ethernet Switches 收發(fā)器數(shù)量:2 數(shù)據(jù)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
KSZ8851-16MLLJ_10 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:Single-Port Ethernet MAC Controller with 8-Bit or 16-Bit Non-PCI Interface