TBR2 and TBR3: 10BASE-T PHY Identifier
(Registers 2 and 3)
ister 3. Register 2, bit 15 corresponds to bit 3 of the
IEEE Identifier and register 2, bit 0 corresponds to bit
18 of the IEEE Identifier. Register 3, bit 15 corresponds
to bit 19 of the IEEE Identifier and register 3, bit 10 cor-
responds to bit 24 of the IEEE Identifier. Register 3, bits
9-4 contain the manufacturer’s model number and bits
3-0 contain the manufacturer’s revision number. These
registers are shown in Table 67 and Table 68.
Registers 2 and 3 contain a unique PHY identifier, con-
sisting of 22 bits of the organizationally unique IEEE
Identifier, a 6-bit manufacturer’s model number, and a
4-bit manufacturer’s revision number. The most signifi-
cant bit of the PHY identifier is bit 15 of register 2; the
least significant bit of the PHY identifier is bit 0 of reg-
Table 67. TBR2: 10BASE-T PHY Identifier (Register 2)
Read/
Write
Bits
15-0
Name
Description
Default Value
Soft Reset
0000000000000000
(0000 Hex)
IEEE Address (bits 3-18); Register
2, bit 15 is MS bit of PHY Identifier
Retains original
Value
PHY_ID[31-16]
RO
Table 68. TBR3: 10BASE-T PHY Identifier (Register 3)
Bits
15-10
Name
Description
Read/Write
Default Value
011010
Soft Reset
IEEE Address (bits 19-
24)
PHY_ID[15-10]
RO
Retains original value
(1A Hex)
110111
Manufacturer’s Model
Number (bits 5-0)
9-4
3-0
PHY_ID[9-4]
PHY_ID[3-0]
RO
RO
Retains original value
Retains original value
(37 Hex)
Revision Number (bits
3-0); Register 3, bit 0is
LS bit of PHY Identifier
0000
Am79C978
191
AMD [ AMD ]
