FALXT972MCCA4 datasheet(54/92 Pages) INTEL

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Intel

® LXT972M Single-Port 10/100 Mbps PHY Transceiver

Datasheet

Document Number: 302875-005

Revision Date: 27-Oct-2005

5.9.4

LED Pulse Stretching

The LED Configuration Register also provides optional LED pulse stretching to 30, 60, or 100 ms.

The pulse stretch time is extended further if the event occurs again during this pulse stretch period.

When an event such as receiving a packet occurs, the event is edge detected and it starts the stretch

timer. The LED driver remains asserted until the stretch timer expires. If another event occurs

before the stretch timer expires, then the stretch timer is reset and the stretch time is extended.

When a long event (such as duplex status) occurs, the event is edge detected and it starts the stretch

timer. When the stretch timer expires, the edge detector is reset so that a long event causes another

pulse to be generated from the edge detector, which resets the stretch timer and causes the LED

driver to remain asserted.

Figure 18 shows how the stretch operation functions.

Figure 18. LED Pulse Stretching

Event

LED

Note: The direct drive LED outputs in this diagram are shown as active L ow.

stretch

B3475-01

FALXT972MCCA4 데이터시트(PDF) 54 Page - Intel Corporation