ksz8851-mql Micrel Semiconductor, ksz8851-mql Datasheet - Page 28

• Manufacturer Part Number: ksz8851-mql
• Description: Single-port Ethernet Mac Controller With 8/16-bit Or 32-bit Non-pci Interface
• Manufacturer: Micrel Semiconductor

LinkMD
The KSZ8851M LinkMD
problems such as open circuits, short circuits, and impedance mismatches.
LinkMD
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
Usage
LinkMD
February 2009
Micrel, Inc.
®
®
®
®
is initiated by accessing register P1SCLMD, the PHY special control/status and LinkMD
works by sending a pulse of known amplitude and duration down the MDI and MDI-X pairs and then analyzes
can be run at any time by ensuring that Auto-MDIX has been disabled. To disable Auto-MDIX, write a ‘1’ to
Cable Diagnostics
B y p a s s A u t o N e g o t i a t i o n
Start Auto Negotiation
Force Link Setting
and Set Link Mode
®
YES
uses time domain reflectometry (TDR) to analyze the cabling plant for common cabling
NO
Figure 6. Auto Negotiation and Parallel Operation
Attempt Auto
Negotiation
Listen for 100BASE-TX
28
Link Mode Set ?
Link Mode Set
Operation
Join Flow
Parallel
Idles
YES
NO
Listen for 10BASE-T L i n k
Pulse s
KSZ8851-16/32 MQL/MQLI
®
register (0xF4).
M9999-021309-1.1