78Q2120C
10/100BASE-TX
Transceiver
MR1: Status Register
BIT
SYMBOL TYPE DEFAULT DESCRIPTION
1.9
100T2_H
R
0
100BASE-T2 Half Duplex Ability:
Reads ‘0’ to indicate the
78Q2120C does not support 100Base-T2 full duplex mode.
1.8
EXTS
R
0
Extended Status Information Availability: Reads ‘0’ to indicate the
78Q2120C does not support Extended Status information on MR15.
1.7
1.6
RSVD
MFPS
R
R
0
0
Reserved
Management Frame Preamble Suppression Support:
A “0”
indicates that the 78Q2120C can read management frames with a
preamble.
1.5
1.4
ANEGC
RFAULT
R
0
0
Auto-Negotiation Complete: A logic one indicates that the Auto-
Negotiation process has been completed, and that the contents of
registers MR4,5,6 are valid.
RC
Remote Fault: A logic one indicates that a remote fault condition
has been detected and remains set until it is cleared. This bit can
only be cleared by reading this register (MR1) via the management
interface.
1.3
1.2
ANEGA
LINK
R
R
(1)
0
Auto-Negotiation Ability: When set, this bit indicates the device’s
ability to perform Auto-Negotiation. The value of this bit is
determined by the ANEGEN bit (MR0.12).
Link Status: A logic one indicates that a valid link has been
established. If the link status should transition from an OK status to
a NOT-OK status, this bit will become cleared and remains cleared
until it is read.
1.1
1.0
JAB
RC
R
0
1
Jabber Detect: In 10Base-T mode, this bit is set during a jabber
event. After a jabber event, the bit remains set until cleared by a
read operation.
EXTD
Extended Capability: Reads ’1’ to indicate the 78Q2120C provides
an extended register set (MR2 and beyond).
MR2: PHY Identifier Register 1
BIT
2.15:0
SYMBOL TYPE VALUE DESCRIPTION
OUI
R
000Eh
Organizationally Unique Identifier: This value is 00-C0-39 for
TERIDIAN Semiconductor Corporation. This register contains the
first 16-bits of the identifier.
[23:6]
MR3: PHY Identifier Register 2
BIT
SYMBOL TYPE VALUE DESCRIPTION
3.15:10
OUI
[5:0]
MN
R
1Ch
Organizationally Unique Identifier: Remaining 6 bits of the OUI.
3.9:4
3.3:0
R
0Ch
Model Number: The last 2 digits of the model number 78Q2120C are
encoded into the 6 bits.
RN
R
9h
Revision Number: The value ‘1001’ corresponds to the ninth revision
of the silicon.
Page: 13 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
