VSC8221 datasheet(93/138 Pages) MICROSEMI

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VSC8221

Data Sheet

VMDS-10106 Revision 4.1

December 2006

93 of 106

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27.11:6 – LED Pin Configuration

Each of the three LED pins on the VSC8221 can be configured for one of four functions. These functions are different for each

LED pin.1 Bits 27.11:6 are used to select the function for each LED pin. The reset value of these bits is set by the LED

configuration bits in the CMODE hardware configuration.

7.5 – LED Pulse-Stretch/Blink Rate

The Collision, Activity, Tx and Rx LED functions can be set to either blink at a constant rate or visibly flash through the use of

pulse-stretching. The blink rate and pulse-stretch length are set with this bit.

27.4 – LED Pulsing Enable

When bit 27.4 is set to “1”, all LED outputs are pulsed at a 5kHz rate with 20% duty cycle in order to save power.

27.3 – LED Pulse-Stretch / Blink Select

When bit 27.3 is set to “1”, Collision, Activity, Tx and Rx LED functions will be pulse-stretched. When bit 27.3 is cleared, these

LED functions will blink at a constant rate. Bit 27.5 are used to select the pulse-stretch / blink rate.

27.2 – LED Link/Activity Behavior

When bit 27.2 is set to “0”, the link status LED function will blink or flash when activity is present. Blink / flash behavior is

selected by bits 27.3 and 27.5.

27.1 – LED Linkxxxx/Activity Behavior

When bit 27.1 is set to “0”, all linkxxxx status LED functions (Link10, Link100, Link1000, Link10/100, Link100/1000) will blink or

flash when activity is present. Blink / flash behavior is selected by bits 27.3 and 27.5.

27.0 – LED Duplex/Collision Behavior

When bit 27.0 is set to “1”, the Duplex LED function indicates duplex status only. When bit 27.0 is cleared, the Duplex function

will blink or flash when collision is present. Blink / flash behavior is selected by bits 27.3 and 27.5.

1Note that if bits 27.7:6 are set to “01”, LED pins 1 and 2 are used as serial output pins and the values of bits 27.11:8 are ignored.

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