TSB81BA3 datasheet(21/57 Pages) TI

21 / 57 page

TSB81BA3, TSB81BA3I

IEEE 1394b THREEPORT CABLE TRANSCEIVER/ARBITER

SLLS559B − DECEMBER 2002 − REVISED OCTOBER 2003

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

power-class programming

The PC0−PC2 terminals are programmed to set the default value of the power-class indicated in the pwr field

(bits 21−23) of the transmitted self-ID packet. Descriptions of the various power-classes are given in Table 9.

The default power-class value is loaded following a hardware reset, but is overridden by any value subsequently

loaded into the Pwr_Class field in register 4.

Table 9. Power Class Descriptions

PC0−PC2

DESCRIPTION

000

Node does not need power and does not repeat power.

001

Node is self-powered and provides a minimum of 15 W to the bus.

010

Node is self-powered and provides a minimum of 30 W to the bus.

011

Node is self-powered and provides a minimum of 45 W to the bus.

100

Node may be powered from the bus and is using up to 3 W, no additional power is needed to enable the link. The node may also

provide power to the bus. The amount of bus power that it provides can be found in the configuration ROM.

101

Reserved for future standardization.

110

Node is powered from the bus and uses up to 3 W. An additional 3 W is needed to enable the link.

111

Node is powered from the bus and uses up to 3 W. An additional 7 W is needed to enable the link.

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