43
ICS1890
MII Management Interface
Management Data Clock
MDC
The Management Data Clock (MDC) is used by the
ICS1890
to synchronize the transfer of management information to or
from the
ICS1890
using the serial MDIO data line.
Management Data Input/Output
MDIO
The Management Data Input/Output (MDIO) is a tri-statable
line driven by station management to transfer command
information or driven by the
ICS1890
to transfer status
information. All transfers and sampling are synchronous with
MDC. If the
ICS1890
is to be used in an application which
uses the mechanical MII specification, MDIO must have a
1.5K
Ω
±5% pull-up at the
ICS1890
end and a 2K
Ω
±5% pull-
down at the station management end. This enables station
management to deter-mine if the connection is intact.
Twisted Pair Interface
Transmit Pair
TP_TX+ & TP_TX-
The Transmit pair TP_TX+ and TP_TX- carries the serial bit
stream for transmission over the UTP cable. The current-
driven differential driver is programmed to produce two-level
(10Base-T, Manchester) or three-level (100Base-TX, MLT-3)
signals depending on the mode of operation selected (manually
or by Auto-Negotiation). These output signals interface directly
with an isolation transformer.
Note that these pins may be tristated using the TPTRI control
pin.
Receive Pair
TP_RX+ & TP_RX-
The Receive pair TP_RX+ and TP_RX- carries the serial bit
stream from the mandatory isolation transformer. The serial bit
stream may be two-level (10Base-T, Manchester) or three-
level (100Base-TX, MLT-3) signals depending on the ICS
mode of operation
10M Transmit Current Set Resistor
10TCSR
A resistor is required to be connected between this pin and
the nearest transmit ground to set the value of the transmit
current used in 10M mode.
The value and tolerance of this resistor is specified in the
Electricals section.
100M Transmit Current Set Resistor
100TCSR
A resistor is required to be connected between this pin and
the nearest transmit ground to set the value of the transmit
current used in 100M mode.
The value and tolerance of this resistor is specified in the
Electricals section.
Clock Reference Interface
Frequency Reference
(REF_IN & REF_OUT)
These pins connect to the 25 MHz crystal or the frequency
reference source.
When a frequency reference source like a crystal oscillator
module is used, its output should be connected to REF_IN
and REF_OUT should be left unconnected.
Configuration and Status Interface
Node/Repeater Mode
NOD/REP
When this input is logic zero, the device will default to Node
operation. SQE test will default to on for 10Base-T.
When this input is logic one, the device will default to Repeater
operation. SQE test will default to off and Carrier Sense will be
determined by receive activity only.
This pin setting also affects which clock, TXCLK or REF_IN,
is used to latch the transmit data, TXD. See the description of
the ITCLS pin for the details.
MII Data/Stream Interface Select
MII/SI
This input pin selects the MAC to PHY interface to be used.
When the input is low the MII Data Interface is selected.
When this input is high, the Stream Interface is selected.
The Stream Interface that is used depends on the settings
of the 10/100SEL and 10/LP pins which allow selection of the
100M Stream Interface, 10M/Serial Interface, or Link Pulse
Interface.
10M Serial/Link Pulse Interface Select
10/LP
This input selects between the 10M Serial and Link Pulse
Interfaces when Stream Interface mode is selected with the
MII/SI pin. When this input is low and Stream Interface mode
is selected, the 10M Serial Interface is selected. When this
input is high and Stream Interface mode is selected, the Link
Pulse Interface is selected.
Summary of Contents for PHYceiver ICS1890
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