Datasheet

TSB81BA3D, TSB81BA3DI
IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER
SLLS559E − DECEMBER 2002 − REVISED JUNE 2006
21
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.