USB3503 datasheet(62/82 Pages) SMSC

62 / 82 page

USB 2.0 HSIC High-Speed Hub Controller Optimized for Portable Applications

Datasheet

SMSC USB3503A

Revision 1.1 (02-07-13)

DATASHEET

When ports are configured for downstream battery charging, the corresponding PRTPWR setting will

be controlled by downstream battery charging logic instead of the normal hub logic.

PRTPWR setting will assert after initial hub customer configuration (Internal default/Serial register

writes). PRTPWR will remain asserted and under the control of the battery charge logic until one of

two events.

1. An overcurrent is detected on the corresponding OCS_N pin. In this case, PRTPWR setting will

negate. The only way to re-enable the PRTPWR setting from this state is to RESET the USB3503.

2. The hub enters Hub.Communication stage, connects on its upstream port and is enumerated by a

USB host. In this case, control over the PRTPWR setting reverts back to the hub logic inside the

USB3503 and the normal USB behavior applies. In this case, the host must enable PRTPWR.

Since the enumeration process for a hub sets the PORT_POWER feature for all downstream ports,

this information can be used to switch control over the PRTPWR setting between the battery charge

logic and the hub logic.



When the Hub PORT_POWER feature is ‘1’, the hub logic controls the PRTPWR setting.



When the Hub PORT_POWER feature is ‘0’, the battery charging logic controls the PRTPWR

setting.

No matter which controller is controlling the PRTPWR setting, an overcurrent event will always negate

PRTPWR setting.

8.1.3

Battery Charging Configuration

Configuration of ports to support battery charging is done through serial port configuration load.

The register, starting from Bit 1, enables Battery charging for each down stream port when asserted.

Bit 1 represents port 1 and so on. Each port with battery charging enabled asserts the corresponding

PRTPWR register bit.

USB3503 Datasheet(PDF) 62 Page - SMSC Corporation