FWLXT9785EBC.D0 Cortina Systems Inc, FWLXT9785EBC.D0 Datasheet - Page 128

• Manufacturer Part Number: FWLXT9785EBC.D0
• Manufacturer: Cortina Systems Inc

Specifications of FWLXT9785EBC.D0

• Lead Free Status / RoHS Status: Not Compliant

LXT9785/LXT9785E
Datasheet
249241, Revision 11.0
16 April 2007
Figure 14
4.6.1.6
4.7
Cortina Systems
Auto-Negotiation Operation
Reliable Link Establishment While Auto MDI/MDIX is Enabled in
Forced Speed Mode
With auto MDI/MDIX hardware enabled, end users experience reliable link establishment
under all settings of auto MDI/MDIX and speed between the LXT9785/LXT9785E and its
link partners. As stated in the IEEE clauses 40.4.5.1 (Auto MDI/MDIX) and 28.3.2 (Parallel
Detect), when ports are forced to 10 Mbps or 100 Mbps and auto MDI/MDIX is enabled,
and the port is connected to a partner with auto-negotiation enabled, an undefined
condition exists between the IEEE auto MDIX and Parallel Detect specifications. Link may
not occur according to the IEEE specification.
During this undefined condition, when the LXT9785/LXT9785E is set to 10 Mbps or 100
Mbps and auto MDI/MDIX is enabled, the LXT9785/LXT9785E and the link partner auto-
negotiation processes are expected to be skewed enough to establish link in all but the
rarest cases. Auto MDI/MDIX is configured through hardware and software. If auto MDI/
MDIX operation is desired in forced modes, disabling auto MDI/MDIX using the software
programming can aid link establishment.
Serial MII Operation
The LXT9785/LXT9785E exchanges transmit and receive data with the controller via the
Serial MII (SMII). The SMII performs the following functions:
®
• Conveys complete MII information between a 10/100 PHY and MAC with two pins per
• Allows a multi-port MAC/PHY communication with one system clock.
• Operates in both half and full-duplex.
• Supports per-packet switching between 10 Mbps and 100 Mbps data rates.
LXT9785 and LXT9785E Advanced 8-Port 10/100 Mbps PHY Transceivers
port.
Auto-Negotiation
Go To Forced
Settings
Disable
Done
0.12 = 0
Power-Up, Reset,
Link Failure
Check Value
Attempt Auto-
Start
0.12
Negotiation
0.12 = 1
YES
Listen for 100TX
Auto-Neg/Parallel Detection
Idle Symbols
Link Set?
Enable
4.7 Serial MII Operation
NO
Listen for 10T
Link Pulses
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