SMSC EVB8700, Руководство пользователя, Страница: 5 / 10

LAN8700 Evaluation Board User Manual
SMSC LAN8700
USER MANUAL
Revision 1.0 (02-23-10)
5
2.2.2 Boot Mode Configuration
The LAN8700 can be configured to boot into a specific mode of operation at power-up via the
MODE[2:0] configuration straps. By default, the MODE[2:0] configuration straps are pulled-up internally
to “1”. Unpopulated pull-down resistor pads are provided for each MODE[2:0] configuration strap.
These pull-down resistors should only be populated when the corresponding MODE[2:0] configuration
strap is desired to default to “0”. A list of the LAN8700 modes and their corresponding pull-down
resistor configurations are shown in
Table 2.3 .
Note 2.1 Refer to the LAN8700 Datasheet for additional information on Repeater mode.
Note 2.2 Refer to the LAN8700 Datasheet for additional information on Power-Down mode.
Table 2.3 MODE[2:0] Resistor Configuration
MODE[2:0] MODE DEFINITIONS
MODE[2:0] PULL-DOWN RESISTORS
R40
(MODE2)
R41
(MODE1)
R42
(MODE0)
000 10BASE-T Half Duplex
Auto-negotiation disabled
Populated Populated Populated
001 10BASE-T Full Duplex
Auto-negotiation disabled.
Populated Populated Unpopulated
010 100BASE-TX Half Duplex
Auto-negotiation disabled
CRS is active during Transmit & Receive
Populated Unpopulated Populated
011 100BASE-TX Full Duplex
Auto-negotiation disabled
CRS is active during Receive
Populated Unpopulated Unpopulated
100 100BASE-TX Half Duplex is advertised
Auto-negotiation enabled.
CRS is active during Transmit & Receive.
Unpopulated Populated Populated
101 Repeater mode ( Note 2.1 )
Auto-negotiation enabled
100BASE-TX Half Duplex is advertised
CRS is active during receive
Unpopulated Populated Unpopulated
110 Power Down mode ( Note 2.2 ) Unpopulated Unpopulated Populated
111 All capable. Auto-negotiation enabled (Default) Unpopulated Unpopulated Unpopulated