ACD82124 Datasheet, PDF (10/48 Pages) List of Unclassifed Manufacturers – 24 Ports 10/100 Fast Ethernet Switch Controller

LED Interface
The ACD82124 provides a wide variety of LED indica-
tors for simple system management. The update of the
LED is completely autonomous and merely requires
low speed TTL or CMOS devices as LED drivers. The
status display is designed to be flexible to allow the
system designer to choose those indicators appropri-
ate for the specification of the equipment.
There are two LED control signals, LEDVLD0 and
LEDVLD1, used to indicate the start and end of the
LED data signal. LEDCLK signal is a 2.5MHz clock
signal. The rising edge of LEDCLK should be used to
latch the LED data signal into the LED driver circuitry.
The LED data signals contain Lnk, Xmt, Rcv, Col, Err,
Adr, Fdx and Spd, which represent Link status, Trans-
mit status, Receive status, Collision indication, Frame
error indication, Port Address learning status, Full du-
plex operation and Operational Speed status respec-
tively. These status signals are sent out sequentially
from port 23 to port 0, once every 50ms. For details
about the timing diagrams of the LED signals, refer to
the chapter of “Timing Description ”
Life Pulse
The ACD82124 continuously sends out life pulses to
the WCHDOG pin when it is operating properly. In a
catastrophic event, the ACD82124 will not send the
life pulse to cause the external watchdog circuitry to
time-up and reset the switch system.
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