SMSC USB2514B Manual De Usuario

USB 2.0 Hi-Speed Hub Controller

Revision 1.0 (3-11-09)

46

SMSC USB251x

 

Note: “Boost” could result in non-USB Compliant parameters, OEM should use a ‘00’ value unless

specific implementation issues require additional signal boosting to correct for degraded USB
signalling levels.

7:6

Reserved

Reserved

5:4

BOOST_IOUT_7

USB electrical signaling drive strength Boost Bit for Downstream Port ‘7’.

‘00’ = Normal electrical drive strength = No boost

‘01’ = Elevated electrical drive strength = Low (~4% boost)

‘10’ = Elevated electrical drive strength = Medium (~ 8% boost)

‘11’ = Elevated electrical drive strength = High (~12% boost)

3:2

BOOST_IOUT_6

USB electrical signaling drive strength Boost Bit for Downstream Port ‘6’.

‘00’ = Normal electrical drive strength = No boost

‘01’ = Elevated electrical drive strength = Low (~4% boost)

‘10’ = Elevated electrical drive strength = Medium (~ 8% boost)

‘11’ = Elevated electrical drive strength = High (~12% boost)

1:0

BOOST_IOUT_5

USB electrical signaling drive strength Boost Bit for Downstream Port ‘5’.

‘00’ = Normal electrical drive strength = No boost

‘01’ = Elevated electrical drive strength = Low (~4% boost)

‘10’ = Elevated electrical drive strength = Medium (~ 8% boost)

‘11’ = Elevated electrical drive strength = High (~12% boost)