3X38FTR Datasheet, PDF (40/64 Pages) Agere Systems – OCTAL-FET (Fast Ethernet Transceiver) for 10Base-T/100Base-TX/FX

3X38FTR 208-Pin SQFP
OCTAL-FET for 10Base-T/100Base-TX/FX
Preliminary Data Sheet
September 2000
Functional Description (continued)
The LED mode of operation is selected at powerup or reset by the LED_MODE [1:0] configuration pins as shown
below.
Table 12. LED Modes
Pin 1
0
0
1
1
Pin 0
0
1
0
1
Mode
Parallel
Reserved
Serial
Bicolor
Outputs
SPEEDLED_[7:0], FDUPLED[7:0], LINKLED[7:0], ACTLED[7:0]
Reserved
SERCLK, SERDATA, SERSTROBE
ACTLED[7:0], LINKLED[7:0]
Additional LED output control can be obtained by using
the management registers. Each LED can be forced
either high or low via register 20 on a per-channel
basis. Any register 20 bit that is set overrides the LED
value, no matter what mode the device is in. In bicolor
mode, the activity and link LEDs can be set to flash at a
320 ms rate by setting register 20, bit 9 for activity and
bit 8 for link, on a per-channel basis. When flash is
activated, the LED will continuously flash at the 320 ms
rate regardless of the link state or data activity state.
The activity LED output can operate in three different
modes: pulse stretching, pulse blinking, or no stretch-
ing or blinking. With no stretching or blinking, the activ-
ity LED will light for as long as there is transmit and/or
receive activity only. When pulse stretching is enabled
by pulling the STRETCH_LED pin high at powerup or
reset, or by setting register 29, bit 7 high, the activity
LED will light approximately 42 ms to 84 ms, when
transmit or receive activity is detected. If the blink func-
tion is enabled by pulling the BLINK_LED pin high at
powerup or reset, or by setting register 29, bit 11 high,
the activity LED will blink 500 ms on 500 ms off every
time transmit or receive activity is detected. If both
blink and stretch are enabled, the activity LED will blink
2.5 s on 2.5 s off, every time a packet is received.
All LED outputs are 10 mA active-high outputs, no
external buffers are required.
Parallel LED Mode
When operating in the parallel LED mode, each chan-
nel has four LED outputs: activity, link, speed, and full
duplex/collision. The activity LED can be stretched or
can blink on transmit or receive activity as described
above. Each of these four LEDs can be forced on or off
by using register 20.
Serial LED Mode
When the serial LED mode is selected, the LED status
information from all eight channels is multiplexed into
one serial LED data stream. The activity LED function
can still be stretched or blink as described above and
each LED output can still be forced high or low as
described above.
The 3X38 contains a serial LED mode. This mode is
selected by holding the input LED mode pin 1 high and
the LED mode pin 0 low. This mode is a 3-pin serial
LED mode.
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Lucent Technologies Inc.