VSC8221 datasheet(85/138 Pages) MICROSEMI

85 / 138 page

VSC8221

Data Sheet

VMDS-10106 Revision 4.1

December 2006

85 of 106

106

22.15 – Disable Link-integrity State Machine1

When bit 22.15 is set to “0”, the VSC8221 link integrity state machine runs automatically. When bit 22.15 is set to “1”, the link

integrity state machine is bypassed and the PHY is forced into link pass status.

22.14 – Disable Jabber Detect1

When bit 22.14 is set to “0”, the VSC8221 automatically shuts off the transmitter when a transmission request exceeds the

iEEE-specified time limit. When bit 22.14 is set to “1”, transmission requests are allowed to be arbitrarily long without shutting

down the transmitter.

22.13 – Reserved

22.12 – SQE Disable Mode2

When bit 22.12 is set to “1”, SQE (Signal Quality Error) pulses are not sent. Note that this control bit applies in 10BASE-T HDX

mode only.

22.11:10 – 10BASE-T Squelch Control2

When bits 22.11:10 are set to “00”, the VSC8221 uses the squelch threshold levels prescribed by the iEEE’s 10BASE-T

specification. When bits 22.11:10 are set to “01”, the squelch level is decreased, which may improve the bit error rate

performance on long loops. When bits 22.11:10 are set to “10”, the squelch level is increased, which may improve the bit error

rate in high-noise environments.

22.9 - Sticky Reset Enable

When bit 22.9 is set, all Mii register bits that are marked with an “S” in the “sticky” column will retain their values during a

software reset. When cleared, all Mii register bits that are marked with an “S” in the “sticky” column will be changed to their

default values during a software reset. Note that bits marked with an “SS” retain their values across software reset regardless of

the setting of bit 22.9.

22.8 – EOF Error2

When bit 22.8 returns a “1”, a defective EOF (End-of-Frame) sequence has been received since the last time this bit was read.

This bit is automatically set to “0” when it is read.

22.7 – 10BASE-T Disconnect State

Bit 22.7 is set to “1” if the 10BASE-T connection has been broken by the carrier integrity monitor since the last read of this bit.

Otherwise, this bit is set to “0”.

22.6 – 10BASE-T Link Status

Bit 22.6 is set to “1” if the 10BASE-T link is active. Otherwise, this bit is set to “0”.

22.5:0 – Reserved

1This bit applies only in 10BASE-T mode.

2This bit applies only in 10BASE-T HDX mode.

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