ICS1894-40
10BASE-T/100BASE-TX INTEGRATED PHYCEIVER WITH RMII INTERFACE
PHYCEIVER
3. Each multi-function configuration pin must be pulled
either up or down with a resistor to establish the address of
the ICS1894-40. LEDs may be placed in series with these
resistors to provide a designated status indicator as
described in the Pins for Monitoring the Data Link table. Use
1KΩ resistors.
Pins for Monitoring the Data Link table
Pin
LED Driven by the Pin’s Output Signal
Link, Activity, Tx, Rx, COL, Mode, Dplx
P0/LED0
P1/ISO/LED1 Link, Activity, Tx, Rx, COL, Mode, Dplx
P4/LED2
LED3
Link, Activity, Tx, Rx, COL, Mode, Dplx
Link, Activity, Tx, Rx, COL, Mode, Dplx
Link, Activity, Tx, Rx, COL, Mode, Dplx
Caution: Pins listed in the Pins for Monitoring the Data Link
table must not float.
4. As outputs, the asserted state of a multi-function
configuration pin is the inverse of the sense sampled during
reset. This inversion provides a signal that can illuminate an
LED during an asserted state. For example, if a
multi-function configuration pin is pulled down to ground
through an LED and a current-limiting resistor, then the
sampled sense of the input is low. To illuminate this LED for
the asserted state, the output is driven high.
SI/LED4
Note:
1. During either power-on reset or hardware reset, each
multi-function configuration pin is an input that is sampled
when the ICS1894-40 exits the reset state. After sampling is
complete, these pins are output pins that can drive status
LEDs.
5. Adding 10KΩresistors across the LEDs ensures the PHY
address is fully defined during slow VDD power-ramp
conditions.
2. A software reset does not affect the state of a
multi-function configuration pin. During a software reset, all
multi-function configuration pins are outputs.
6. PHY address 00 tri-states the MII interface. (Do not select
PHY address 00 unless you want the MII tri-stated.)
The following figure shows typical biasing and LED connections for the ICS1894-40.
ICS1894-40
P4/LED2
(set high
internally)
P3/RXD2
P2//INT
P1/ISO/LED1
40
P0/LED0
39
19
12
38
INT
RXD2
VDD
1KΩ
10KΩ
10KΩ
LED1
10KΩ
1KΩ
LED0
10KΩ
The above circuit decodes the PHY address = 17
IDT® 10BASE-T/100BASE-TX INTEGRATED PHYCEIVER WITH RMII INTERFACE
15
ICS1894-40
REV G 060110
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
