UCS2112 Dual USB Port Power Evaluation Board User’s Guide
DS50002420A-page 26
2015 Microchip Technology Inc.
2.
In the
System Monitoring
tab, set the Charge Rationing threshold.
The Charge Rationing threshold value (default set to maximum) can be modified
by entering a new number in the corresponding box. After pressing the <Enter>
key, the software adjusts the number to the closest value that can be written to
the UCS2112 Charge Rationing registers.
In the same tab, the user can set the Current Limit for each Port, by selecting one
of the values from the drop-down list (see
4.2.4
ALERT# pin assertion and fault handling
When an ALERT# pin of the UCS2112 device is asserted because is exceeding the
Current Limit, reaching the Charge Rationing Limit or any other fault condition
mentioned in the UCS2112 data sheet, the on-board hub USB84604 detects this
condition as an overcurrent fault in all cases. This fault is signaled by the Windows
operating system. The hub disables the corresponding port power switch automatically
by setting the corresponding PWR_EN pin low. To enable the power switch back and
set the PWR_EN pin high, click on the Windows notification balloon and reset the
corresponding port.
To disable the hub from automatically controlling the power switch, check the
Ignore
PWR_EN pins
option from the
Advance Configuration
). The
PWR_EN controls will be determined only by the state of the PWR_EN1 bit and
PWR_EN2 bit, which can be set or cleared in the same section.
FIGURE 4-6:
Advanced Configuration Tab - PWR_EN Control Overrides.