USB2532 Datasheet, PDF (33/50 Pages) SMSC Corporation – USB 2.0 Hi-Speed 2-Port Hub Controller

USB 2.0 Hi-Speed 2-Port Hub Controller
Datasheet
Table 8.1 Chargers Compatible with Upstream Detection (continued)
USB ATTACH TYPE
Apple Charger Low Current Charger (500mA)
Apple Charger High Current Charger (1000mA)
DP/DM PROFILE
DP=2.0V
DM=2.0V
DP=2.0V
DM=2.7V
CHARGERTYPE
100
101
If a custom charger detection algorithm is desired, the SMBus registers can also be used to control
the charger detection block to implement a custom charger detection algorithm. In order to avoid
negative interactions with automatic battery charger detection or normal hub operation, the user should
only attempt Custom battery charger detection during the Hub.Config stage or Hub.Connect stage. No
logic is implemented to disable custom detection at other times - it is up to the user software to observe
this restriction.
There is a possibility that the system is not running the reference clock when battery charger detection
is required (for example if the battery is dead or missing). During the Hub.WaitRefClk stage the battery
charger detection sequence can be configured to be followed regardless of the activity of REFCLK by
relying on the operation of the internal oscillator.
8.1.2
Downstream Battery Charging
The device can be configured by an OEM to have any of the downstream ports to support battery
charging. The Hub's role in battery charging is to provide an acknowledge to a device's query as to if
the hub system supports USB battery charging. The hub silicon does not provide any current or power
FETs or any additional circuitry to actually charge the device. Those components must be provided as
externally by the OEM.
INT
SSDC^MAL^{icHroucbShOipC}
PRTPWR[n]
DC Power
VBUS[n]
Figure 8.1 Battery Charging External Power Supply
If the OEM provides an external supply capable of supplying current per the battery charging
specification, the hub can be configured to indicate the presence of such a supply to the device. This
indication, via the PRTPWR[1:4] output pins, is on a per/port basis. For example, the OEM can
configure two ports to support battery charging through high current power FET's and leave the other
two ports as standard USB ports.
8.1.2.1
Downstream Battery Charging Modes
In the terminology of the USB Battery Charging Specification, if a port is configured to support battery
charging, the downstream port is a considered a CDP (Charging Downstream Port) if connected to a
 2014 Microchip Technology Inc.
DS00001701A-page 33