LAN9221 Datasheet, PDF (18/151 Pages) SMSC Corporation – High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
NAME
Crystal 1, Clock In
Crystal 2
Reset
Table 2.4 System and Power Signals
SYMBOL
XTAL1/CLKIN
XTAL2
nRESET
BUFFER
TYPE
lCLK
OCLK
VIS
(PU)
NUM
PINS
1
1
1
DESCRIPTION
External 25MHz Crystal Input. This pin can also
be connected to single-ended TTL oscillator
(CLKIN). If this method is implemented, XTAL2
should be left unconnected.
External 25MHz Crystal output.
Active-low reset input. Resets all logic and
registers within the LAN9221/LAN9221i. This
signal is pulled high with a weak internal pull-up
resistor.
Note:
The LAN9221/LAN9221i must be reset
on power-up via nRESET or following
power-up via a soft reset (SRST). The
LAN9221/LAN9221i must always be
read at least once after reset, or upon
return from a power-saving state or
write operations will not function. See
Section 3.11, "Detailed Reset
Description," on page 48 for additional
information
Note:
When operating at reduced
VDDVARIO voltage levels (less than
3.0V), this pin must be pulled-high to
a valid level with an external resistor
or must be driven as an input. Refer to
Section 2.2, "External Pull-Up/Pull-
Down Resistors" for more information.
Wakeup Indicator
PME
VO8/
VOD8
1
When programmed to do so, is asserted when
the LAN9221/LAN9221i detects a wake event
and is requesting the system to wake up from
the associated sleep state. The polarity and
buffer type of this signal is programmable.
Note:
Detection of a Power Management
Event, and assertion of the PME
signal will not wakeup the
LAN9221/LAN9221i. The
LAN9221/LAN9221iwill only wake up
when it detects a host write cycle
(assertion of nCS and nWR). Although
any write to the LAN9221/LAN9221i,
regardless of the data written, will
wake-up the device when it is in a
power-saving mode, it is required that
the BYTE_TEST register be used for
this purpose.
Revision 2.6 (12-04-08)
18
DATASHEET
SMSC LAN9221/LAN9221i