Intel 82555 manual 150

Networking Silicon — 82555

Bit(s)	Name		Description	Default	R/W
13	Force Transmit H-	1	= Force transmit H-pattern	0	RW
	Pattern	0	= Normal operation
12	Force 34 Transmit	1	= Force 34 transmit pattern	0	RW
	Pattern	0	= Normal operation
11	Good Link	1 = 100BASE-TX link good		0	RW
		0	= Normal operation
10	Reserved	This bit is reserved and should be set to 0b.		0	RW
9	Transmit Carrier	1	= Transmit Carrier Sense disabled	0	RW
	Sense Disable	0	= Transmit Carrier Sense enabled
8	Disable Dynamic	1	= Dynamic Power-Down disabled	0	RW
	Power-Down	0	= Dynamic Power-Down enabled (normal)
7	Auto-Negotiation	1	= Auto-Negotiation loopback	0	RW
	Loopback	0	= Auto-Negotiation normal mode
6	MDI Tri-State	1	= MDI Tri-state (transmit driver tri-states)	0	RW
		0	= Normal operation
5	Filter By-pass	1	= By-pass filter	0	RW
		0	= Normal filter operation
4	Auto Polarity	1	= Auto Polarity disabled	0	RW
	Disable	0	= Normal polarity operation
3	Squelch Disable	1	= 10BASE-T squelch test disable	0	RW
		0	= Normal squelch operation
2	Extended	1	= 10BASE-T Extended Squelch control enabled	--	RW
	Squelch	0	= 10BASE-T Extended Squelch control disabled
1	Link Integrity	1	= Link disabled	0	RW
	Disable	0	= Normal Link Integrity operation
0	Jabber Function	1	= Jabber disabled	0	RW
	Disable	0	= Normal Jabber operation

7.2.3.3Register 20: 100BASE-TX Receive Disconnect Counter Bit Definitions

Bit(s)	Name	Description	Default	R/W
15:0	Disconnect Event	This field contains a 16-bit counter that increments for	--	RO
		each disconnect event. The counter stops when full		SC
		(and does not roll over) and self-clears on read
		In repeater mode, a frame that starts without “JK” is a
		disconnect event.

7.2.3.4Register 21: 100BASE-TX Receive Error Frame Counter Bit Definitions

Bit(s)	Name	Description	Default	R/W
15:0	Receive Error	This field contains a 16-bit counter that increments	--	RO
	Frame	once per frame for any receive error condition (such		SC
		as a symbol error or premature end of frame) in that
		frame. The counter stops when full (and does not roll
		over) and self-clears on read.

Datasheet 33