Datasheet

USB 2.0 Hi-Speed Hub Controller
Datasheet
SMSC USB251x 45 Revision 1.1 (04-26-10)
DATASHEET
8.2.1.26 Register D0h: Battery Charging Enable
8.2.1.27 Register F6h: Boost_Up
8.2.1.28 Register F7h: Boost_7:5
BIT
NUMBER BIT NAME DESCRIPTION
7:0 BC_EN Only available in USB251xB/Bi hub family products.
Battery Charging Enable: Enables the battery charging feature for the
corresponding port.
'0' = Battery Charging support is not enabled
'1' = Battery charging support is enabled
Bit 7= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Controls Port 4
Bit 3= Controls Port 3
Bit 2= Controls Port 2
Bit 1= Controls Port 1
Bit 0= Reserved
BIT
NUMBER BIT NAME DESCRIPTION
7:2 Reserved Reserved
1:0 BOOST_IOUT USB electrical signaling drive strength Boost Bit for the Upstream Port.
‘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)
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.
BIT
NUMBER BIT NAME DESCRIPTION
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)