ICS1892 Datasheet, PDF (105/148 Pages) Integrated Circuit Systems – 10Base-T/100Base-TX Integrated PHYceiver

ICS1892
Chapter 9 Pin Diagram, Listings, and Descriptions
9.2.2 Multi-Function (Multiplexed) Pins: PHY Address and LED Pins
Table 9-4 lists the pins for the multifunction group of pins (that is, the multiplexed PHY Address / LED pins).
Note:
1. During either a power-on reset or a hardware reset, each multi-function configuration pin is an input
that is sampled when the ICS1892 exists 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 ICS1892. LEDs placed in series with these resistors provide a designated status
indicator.
Caution: All pins listed inTable 9.4 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 an LED for the
asserted state requires the output to be high.
Caution: PHY Address 00 will tri-state the MII interface.
Note: Each of these pins monitor the data link by providing signals that directly drive LEDs.
Table 9-4. PHY Address and LED Pins
Pin
Name
P0AC,
P1CL,
P2LI,
P3TD,
P4RD
Pin
Number
58,
59,
60,
61,
62
Pin
Type
Input or
Output
Pin Description
PHY (Address Bit) 0 / Activity LED.
PHY (Address Bit) 1 / Collision LED.
PHY (Address Bit) 2 / Link Integrity LED.
PHY (Address Bit) 3 / Transmit Data LED.
PHY (Address Bit) 4 / Receive Data LED.
The ‘Pin Type’ for these multiplexed pins depends on the where the
ICS1892 is in its reset cycle.
• During a reset of the ICS1892, these pins act as inputs.
• After a reset of the ICS1892, these pins latch the state of the inputs into
their respective PHY Address bits. (See Table 8-16.) The ICS1892 then
converts the pin signal to an output that can drive the respective LED
directly.
For more information, see Section 6.9, “Status Interface”.
ICS1892, Rev. D, 2/26/01
© 2000-2001, Integrated Circuit Systems, Inc.
All rights reserved.
105
February 26, 2001