78Q2120C Teridian Semiconductor Corp. (TDK Semiconductor), 78Q2120C Datasheet - Page 12

• Manufacturer Part Number: 78Q2120C
• Description: 10/100 Ethernet PHYS
• Manufacturer: Teridian Semiconductor Corp. (TDK Semiconductor)

MR0: Control Register (continued)
MR1: Status Register
Bits 1.15 through 1.11 reflect the ability of the 78Q2120C as configured by the TECH[2:0] pins. They do not
reflect any ability changes made via the MII Management interface to bits 0.13 (SPEEDSL) , 0.12 (ANEGEN) and
0.8 (DUPLEX).
© 2003 TDK Semiconductor Corporation, Proprietary and Confidential
1.15
1.14
1.13
1.12
1.11
1.10
0.6:0
Bit
0.8
0.7
Bit
100T4
100X_F
100X_H
10T_F
10T_H
100T2_F
DUPLEX
Symbol
Symbol
RSVD
COLT
R
R
R
R
R
R
Type
Type
R/W
R/W
R
0
(1)
(1)
(1)
(1)
0
Default Description
Default Description
(1)
0
0
Duplex Mode: This bit determines whether the device supports full-
duplex or half-duplex. A ‘1’ indicates full-duplex operation and a ‘0’
indicates half-duplex.
TECH[2:0] pins are all logic zero and auto-negotiation is not enabled,
this bit will be writeable. If auto-negotiation is not enabled and the
TECH[2:0] pins are set to indicate that only full-duplex is supported,
this bit will be forced to ‘1’ and will not be writeable. If auto-negotiation
is not enabled and the TECH[2:0] pins are set to indicate that only
half-duplex is supported, this bit will be forced to ‘0’ and will not be
writeable.
writeable and will have no effect on the device. If the TECH[2:0] pins
are brought to zero from another value, this bit will retain its original
value until it is overwritten.
Collision Test: When this bit is set to ‘1’, the device will assert the
COL signal in response to the assertion of the TX_EN signal.
Collision test is disabled if the PCSBP pin is high. Collision test can
be activated regardless of the duplex mode of operation.
Reserved
100BASE-T4 Ability: Reads ‘0’ to indicate the 78Q2120C does not
support 100Base-T4 mode.
100BASE-TX Full Duplex Ability:
100BASE-TX Half Duplex Ability:
10BASE-T Full Duplex Ability:
10BASE-T Half Duplex Ability:
100BASE-T2 Full Duplex Ability: Reads ‘0’ to indicate the 78Q2120C
does not support 100Base-T2 full duplex mode.
0 : Not able
1 : Able
0 : Not able
1 : Able
0 : Not able
1 : Able
0 : Not able
1 : Able
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When auto-negotiation is enabled, this bit will not be
10/100BASE-TX Transceiver
This bit will default to ‘0’ upon reset, if the
78Q2120C
Rev_1.1