USB2640I Standard Microsystems Corp., USB2640I Datasheet - Page 43

• Manufacturer Part Number: USB2640I
• Description: Industrial Temperature Usb 2.0 Flash Media Controller And Usb Hub Combo
• Manufacturer: Standard Microsystems Corp.

Industrial Temperature USB 2.0 Flash Media Controller and USB Hub Combo
SMSC USB2640i/USB2641i
7.3.3.28
7.3.3.29
NUMBER
NUMBER
BIT
BIT
7:2
1:0
7:6
5:4
3:2
1:0
EFh: Boost_Up
F0h: Boost_3:0
BOOST_IOUT_3
BOOST_IOUT_2
BOOST_IOUT
BIT NAME
BIT NAME
Reserved
Reserved
Reserved
Always reads ‘0’.
Upstream USB electrical signaling drive strength Boost Bit for Downstream
Upstream USB electrical signaling drive strength Boost Bit for Downstream
Always reads ‘0’.
Reserved
USB electrical signaling drive strength Boost Bit for the Upstream Port ‘A’.
‘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:
Port ‘3’.
‘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)
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), OEM should use a ‘00’ value
unless specific implementation issues require additional signal
boosting to correct for degraded USB signalling levels.
“Boost” could result in non-USB Compliant parameters (one
example would be Test J/K levels), OEM should use a ‘00’ value
unless specific implementation issues require additional signal
boosting to correct for degraded USB signalling levels.
DATASHEET
43
DESCRIPTION
DESCRIPTION
Revision 2.0 (10-03-08)