ICS1894-33
10BASE-T/100BASE-TX INTEGRATED PHYCEIVER WITH RMII INTERFACE PHYCEIVER
IDT®
10BASE-T/100BASE-TX INTEGRATED PHYCEIVER WITH RMII INTERFACE 13
ICS1894-33 REV A 021612
Pins for Monitoring the Data Link table
Note:
1. During either power-on reset or hardware reset, each
multi-function configuration pin is an input that is sampled
when the ICS1894-33 exits the reset state. After sampling is
complete, these pins are output pins that can drive status
LEDs.
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.
3. Each multi-function configuration pin must be pulled
either up or down with a resistor to establish the address of
the ICS1894-33. 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.
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.
5. Adding 10KΩ resistors across the LEDs ensures the PHY
address is fully defined during slow VDD power-ramp
conditions.
6. PHY address 00 tri-states the RMII interface. (Do not
select PHY address 00 unless you want the RMII interface
tri-stated.)
The following figure shows typical biasing and LED connections for the ICS1894-33.
The above circuit decodes the PHY address = 1
Pin Status Events that drive the LEDs
P0/LED0 Link, Activity, Tx, Rx, Mode, Dplx
P1/ISO/LED1 Link, Activity, Tx, Rx, Mode, Dplx
ICS1894-33
32 31
P1/ISO/LED1 P0/LED0
LED0
1KΩ
10KΩ
VDD
LED1
1KΩ
10KΩ
