USB2642 Datasheet, PDF (33/56 Pages) Microchip Technology – USB 2.0 Hub and Flash Media Card Controller Combo

USB2642
7.4.3.22 ECh: Hub Controller Max Current For Self-Powered Operation
Bit
Name
Description
7:0
HC_MAX_C_SP Value in 2 mA increments that the hub consumes from an upstream port
(VBUS) when operating as a self-powered hub. This value includes the hub
silicon along with the combined power consumption (from VBUS) of all
associated circuitry on the board. This value does NOT include the power
consumption of a permanently attached peripheral if the hub is configured
as a compound device.
Note: The USB 2.0 Specification (References) does not permit this value
to exceed 100 mA.
A value of 50 (decimal) indicates 100 mA, which is the default value.
7.4.3.23 EDh: Hub Controller Max Current For Bus-Powered Operation
Bit
Name
Description
7:0
HC_MAX_C_BP Value in 2 mA increments that the hub consumes from an upstream port
(VBUS) when operating as a bus-powered hub. This value will include the
hub silicon along with the combined power consumption (from VBUS) of all
associated circuitry on the board. This value will NOT include the power
consumption of a permanently attached peripheral if the hub is configured
as a compound device.
A value of 50 (decimal) would indicate 100 mA, which is the default value.
7.4.3.24 EEh: Power-On Time
Bit
Name
Description
7:0
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 adequate on that
port. If the host requests the power-on time, the system software uses this
value to determine how long to wait before accessing a powered-on port.
7.4.3.25 EFh: Boost_Up
Bit
Name
Description
7:2
rsvd
1:0
BOOST_IOUT
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:
“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
signaling levels.
 2014-2015 Microchip Technology Inc.
DS00001578C-page 33