LAN8187_06 SMSC [SMSC Corporation], LAN8187_06 Datasheet - Page 53

• Manufacturer Part Number: LAN8187_06
• Manufacturer: SMSC [SMSC Corporation]

±15kV ESD Protected MII/RMII Fast-Ethernet PHY with HP Auto-MDIX and SMSC flexPWR
Datasheet
SMSC LAN8187/LAN8187I
5.4.8
5.4.8.1
5.4.9
5.4.9.1
5.4.9.2
MODE[2:0]
000
001
010
100
101
011
110
The Full-Duplex LED output is driven active low when the link is operating in Full-Duplex mode.
Loopback Operation
The 10/100 digital has two independent loop-back modes: Internal loopback and far loopback.
Internal Loopback
The internal loopback mode is enabled by setting bit register 0 bit 14 to logic one. In this mode, the
scrambled transmit data (output of the scrambler) is looped into the receive logic (input of the
descrambler). The COL signal will be inactive in this mode, unless collision test (bit 0.7) is active.
In this mode, during transmission (TX_EN is HIGH), nothing is transmitted to the line and the
transmitters are powered down.
Configuration Signals
The PHY has 11 configuration signals whose inputs should be driven continuously, either by external
logic or external pull-up/pull-down resistors.
Physical Address Bus - PHYAD[4:0]
The PHYAD[4:0] signals are driven high or low to give each PHY a unique address. This address is
latched into an internal register at end of hardware reset. In a multi-PHY application (such as a
repeater), the controller is able to manage each PHY via the unique address. Each PHY checks each
management data frame for a matching address in the relevant bits. When a match is recognized, the
PHY responds to that particular frame. The PHY address is also used to seed the scrambler. In a multi-
PHY application, this ensures that the scramblers are out of synchronization and disperses the
electromagnetic radiation across the frequency spectrum.
Mode Bus – MODE[2:0]
The MODE[2:0] bus controls the configuration of the 10/100 digital block.
10Base-T Half Duplex. Auto-negotiation disabled.
10Base-T Full Duplex. Auto-negotiation disabled.
100Base-TX Half Duplex. Auto-negotiation
disabled.
CRS is active during Transmit & Receive.
100Base-TX Full Duplex. Auto-negotiation disabled.
CRS is active during Receive.
100Base-TX Half Duplex is advertised. Auto-
negotiation enabled.
CRS is active during Transmit & Receive.
Repeater mode. Auto-negotiation enabled.
100Base-TX Half Duplex is advertised.
CRS is active during Receive.
Power Down mode. In this mode the PHY wake-up
in Power-Down mode.
MODE DEFINITIONS
Table 5.47 MODE[2:0] Bus
DATASHEET
53
TM
DEFAULT REGISTER BIT VALUES
REGISTER 0
[13,12,10,8]
0000
0001
1000
1001
1100
1100
N/A
Revision 1.0 (12-14-06)
REGISTER 4
[8,7,6,5]
0100
0100
N/A
N/A
N/A
N/A
N/A