ksz8021rnli Micrel Semiconductor, ksz8021rnli Datasheet - Page 21

• Manufacturer Part Number: ksz8021rnli
• Description: 10base-t/100base-tx Phy With Rmii Support
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
LinkMD
The LinkMD
such as open circuits, short circuits and impedance mismatches.
LinkMD
shape of the reflected signal to determine the type of fault. The time duration for the reflected signal to return provides the
approximate distance to the cabling fault. The LinkMD
numerical value that can be translated to a cable distance.
LinkMD
PHY Control 2 Register. The latter register is used to disable auto MDI/MDI-X and to select either MDI or MDI-X as the
cable differential pair for testing.
NAND Tree Support
The KSZ8021/31RNL provides parametric NAND tree support for fault detection between chip I/Os and board. The NAND
tree is a chain of nested NAND gates in which each KSZ8021/31RNL digital I/O (NAND tree input) pin is an input to one
NAND gate along the chain. At the end of the chain, the TXD1 pin provides the output for the nested NAND gates.
The NAND tree test process includes:
Table 5 lists the NAND tree pin order.
August 2010
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Enabling NAND tree mode
Pulling all NAND tree input pins high
Driving low each NAND tree input pin sequentially per the NAND tree pin order
Checking the NAND tree output to ensure there is a toggle high-to-low or low-to-high for each NAND tree input
driven low
works by sending a pulse of known amplitude and duration down the MDI or MDI-X pair, and then analyzing the
is initiated by accessing register 1Dh, the LinkMD
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Cable Diagnostics
function utilizes time domain reflectometry (TDR) to analyze the cabling plant for common cabling problems,
Table 5. NAND Tree Test Pin Order – for KSZ8021/31RNL
Pin Number
10
11
12
13
15
16
17
18
19
20
23
21
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Pin Name
REF_CLK
CRS_DV
INTRP
RXER
MDIO
RXD1
RXD0
TXEN
TXD0
TXD1
function processes this TDR information and presents it as a
LED0
MDC
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Control/Status Register, in conjunction with register 1Fh, the
21
Description
NAND Tree
Output
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
KSZ8021RNL / KSZ8031RNL
M9999-082710-1.0