SMSC USB2514 - Manual (Page 29)

USB 2.0 High-Speed 4-Port Hub Controller
Datasheet
SMSC USB2514 29 Revision 1.98 (11-19-07)
DATASHEET
4.3.1.25 Register 92h-CFh: Serial String
4.3.1.26 Register F6h: Boost_Up
BIT
NUMBER BIT NAME DESCRIPTION
7:0 SER_STR Serial String, UNICODE UTF16LE per USB 2.0 Specification
Maximum string length is 31 characters (62 bytes)
Note: The String consists of individual 16 Bit UNICODE UTF-16LE
characters. The Characters will be stored starting with the LSB at
the least significant address and the MSB at the next 8-bit location
(subsequent characters must be stored in sequential contiguous
address in the same LSB, MSB manner). Some EEPROM
programmers may transpose the MSB and LSB, thus reversing the
Byte order. Please pay careful attention to the Byte ordering or
your selected programming tools.
BIT
NUMBER BIT NAME DESCRIPTION
7:2 Reserved Reserved
1:0 BOOST_IOUT Upstream USB electrical signaling drive strength Boost Bit for 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.