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10/100 Mbps Ethernet Controller Family Open Source Software Developer Manual 121
Physical Layer Interface
7.2.3 Identification Registers: Registers 2 and 3
The 32-bit ID register provides a mechanism for software to determine which PHY is present. The
contents of these registers differ depending on the PHY. There are three values encoded in registers
2 and 3 that uniquely identify the PHY device:
• The OUI of the PHY manufacture.
• The model number of the PHY.
• The revision number of the PHY.
The OUI is a 24-bit manufacturer identification number. Only the least significant 22 bits of the
OUI are stored in the registers. The two most significant bits, bits 23:22, are fixed at 0. Bits 21:6 of
the OUI are stored in register 2 while the remaining bits of the OUI, bits 5:0, are stored in bits
15:10 of register 3. (The Intel manufacturer OUI number is “00AA00h.”)
The model number is a 6-bit value assigned by the manufacturer identifying the PHY model. It is
stored in bits 9:4 of register 3. (The Intel PHY model number is “010101.”)
The revision number is a 4-bit value assigned by the manufacturer identifying the PHY revision
number. The Intel devices use revision numbers “0000” through “0100.” The Intel 82558 has a
revision ID number of 0000b, and the 82559, 0100b.
The map below shows how the these three numbers (OUI, model and revision numbers) are
mapped into the MDI registers.
The PHY identification register values are as follows:
2 Link Status (LINKFLT) RO
1 = Valid link
0 = Invalid link
Sticky bit
1 Jabber Detect (JABFLT) RO
1 = Jabber condition detected
0 = No jabber condition detected
NOTE: This bit is only valid in 10 Mbps mode.
Sticky bit
0 Extended Capabilities RO
1= Extended register capabilities
0 = Basic register set capabilities only
1
Bit Name R / W Description Default
Table 61. 24-bit OUI Identification Number
Manufacturer OUI
OUI
Model Revision
23:22 21:6 5:0
Intel 00AA00h 00b 00 0000 1010 1010 00b 00 0000b
Intel 82555 00AA00h 00b 00 0000 1010 1010 00b 00 0000b 010101b 0000b
Table 62. MDI Identification Registers 2 and 3: PHY ID Encoding
MDI Register
Intel 82555
(Revision 4)
Intel 82555
(Revision 1)
Intel 82555
(Revision 0)
Register 2 02A8h 02A8h 02A8h
Register 3 0154h 0151h 0150h