USB MultiSwitchTM Hub

Datasheet

1.1OEM Selectable Features

A default configuration is available in the USB2524 following a reset. This configuration may be sufficient for some applications. Strapping option pins make it possible to modify a limited sub-set of the configuration options.

The USB2524 may also be configured by an external EEPROM or a microcontroller. When using the microcontroller interface, the Hub appears as an SMBus slave device. If the Hub is pin-strapped for external EEPROM configuration but no external EEPROM is present, then a value of ‘0’ will be written to all configuration data bit fields (the hub will attach to the host with all ‘0’ values).

The USB2524 supports several OEM selectable features:

„Optional OEM configuration via I2C EEPROM or via the industry standard SMBus interface from an external SMBus Host or Microcontroller.

„Compound device support (port is permanently hardwired to a downstream USB peripheral device).

„Hardware strapping options enable configuration of the following features (when not configured via an EEPROM or SMBus host).

Non-Removable Ports

Port Power Polarity (active high or active low logic)

„Selection of Single (STT) or Multi-Transaction Translator (MTT) capability.

„Selection of Over-Current sensing and Port power control on a individual (port-by-port) or ganged (all ports together) to match the OEM’s choice of circuit board component selection.

„Selection of end-user method of switching ports between hosts

-Embedded Mode: 8 default configurations that are controlled by OEM programmable registers (or Internal default settings).

-Peripheral Mode: Each wire directly controls one of the 4 downstream ports. The interface is selectable between edge triggered operation or level triggered operation for compatibility with many different mechanical switch configurations or direct control from an external Microcontroller’s GPIO pins.

„Enablement of String Descriptor Support, along with the capability to customize each of the 3 different string descriptors (up to a maximum size of 31 characters each)

„Selection of LED Mode: USB Mode, Host Ownership Mode, or Host Ownership Mode with Speed Indication.

SMSC USB2524

9

Revision 1.91 (08-22-07)

 

DATASHEET