Datasheet – SMSC USB2512 User Manual
Page 21
USB 2.0 High-Speed 2-Port Hub Controller
Datasheet
SMSC USB2512
21
Revision 1.92 (11-28-07)
DATASHEET
4.2.1.17
Register 10h: Power-On Time
4.2.1.18
Register F6h: Boost_Up
4.2.1.19
Register F8h: Boost_2:0
BIT
NUMBER
BIT NAME
DESCRIPTION
7:0
POWER_ON_TIME
Power On Time: The length of time that it takes (in 2 ms intervals) from the
time the host initiated power-on sequence begins on a port until power is
good on that port.
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 (approximately 4% boost)
‘10’ = Elevated electrical drive strength = Medium (approximately 8% boost)
‘11’ = Elevated electrical drive strength = High (approximately 12% boost)
Note:
“Boost” could result in non-USB Compliant parameters (one
example would be Test J/K levels), the 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
7:4
Reserved
Reserved
3:2
BOOST_IOUT_2
USB electrical signaling drive strength Boost Bit for Downstream Port ‘2’.
‘00’ = Normal electrical drive strength = No boost
‘01’ = Elevated electrical drive strength = Low (approximately 4% boost)
‘10’ = Elevated electrical drive strength = Medium (approximately 8% boost)
‘11’ = Elevated electrical drive strength = High (approximately 12% boost)
Note:
“Boost” could result in non-USB Compliant parameters (one
example would be Test J/K levels), the OEM should use a 00 value
unless specific implementation issues require additional signal
boosting to correct for degraded USB signalling levels.
1:0
BOOST_IOUT_1
USB electrical signaling drive strength Boost Bit for Downstream Port ‘1’.
‘00’ = Normal electrical drive strength = No boost
‘01’ = Elevated electrical drive strength = Low (approximately 4% boost)
‘10’ = Elevated electrical drive strength = Medium (approximately 8% boost)
‘11’ = Elevated electrical drive strength = High (approximately 12% boost)
Note:
“Boost” could result in non-USB Compliant parameters (one
example would be Test J/K levels), the OEM should use a 00 value
unless specific implementation issues require additional signal
boosting to correct for degraded USB signalling levels.