lan8720 Standard Microsystems Corp., lan8720 Datasheet - Page 15

• Manufacturer Part Number: lan8720
• Description: Small Footprint Rmii 10/100 Ethernet Transceiver With Hp Auto-mdix Support
• Manufacturer: Standard Microsystems Corp.

Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
SMSC LAN8720/LAN8720i
3.1
3.2
REGOFF
SIGNAL
CRS_DV/
PHYAD0
SIGNAL
NAME
MODE0
MODE1
MODE2
LED1/
RXER/
NAME
RXD0/
RXD1/
TXEN
TXD0
TXD1
MAC Interface Signals
LED Signals
24-QFN
24-QFN
PIN #
PIN #
3
17
18
16
10
11
8
7
TYPE
IOPD
TYPE
IOPU
IOPU
IOPD
IOPU
IPD
I8
I8
LED1 – Link activity LED Indication.
See
Regulator Off: This pin may be used to configure the internal 1.2V regulator
off. As described in
sequence to determine if the internal regulator should turn on. When the
regulator is disabled, external 1.2V must be supplied to VDDCR.
Transmit Data 0: The MAC transmits data to the PHY using this signal in
all modes.
Transmit Data 1: The MAC transmits data to the PHY using this signal in
all modes
Transmit Enable: Indicates that valid data is presented on the TXD[1:0]
signals, for transmission.
Receive Data 0: Bit 0 of the 4 data bits that are sent by the PHY in the
receive path.
PHY Operating Mode Bit 0: set the default MODE of the PHY.
Receive Data 1: Bit 1 of the 4 data bits that are sent by the PHY in the
receive path.
PHY Operating Mode Bit 1: set the default MODE of the PHY.
Receive Error: Asserted to indicate that an error was detected somewhere
in the frame presently being transferred from the PHY.
RMII Mode CRS_DV (Carrier Sense/Receive Data Valid) Asserted to
indicate when the receive medium is non-idle. When a 10BT packet is
received, CRS_DV is asserted, but RXD[1:0] is held low until the SFD byte
(10101011) is received. In 10BT, half-duplex mode, transmitted data is not
looped back onto the receive data pins, per the RMII standard.
PHY Operating Mode Bit 2: set the default MODE of the PHY.
When LED1/REGOFF is pulled high to VDD2A with an external resistor, the
internal regulator is disabled.
When LED1/REGOFF is floating or pulled low, the internal regulator is
enabled (default).
See
See
The RXER signal is optional in RMII Mode.
This signal is mux’d with PHYAD0
See
See
Table 3.2 RMII Signals 24-QFN
Table 3.3 LED Signals 24-QFN
Section 5.3.7
Section 5.3.9.2
Section 5.3.9.2
Section 5.3.9.1
Section 5.3.9.2
DATASHEET
for a description of LED modes.
15
Section
for information on the MODE options.
for information on the MODE options.
for information on the ADDRESS options.
for information on the MODE options.
4.11, this pin is sampled during the power-on
DESCRIPTION
DESCRIPTION
Revision 1.0 (04-15-09)