Industrial Temperature Rated USB 2.0 High-Speed 2-Port Hub Controller

Datasheet

4.3.5Stretching the SCLK Signal

The Hub supports stretching of the SCLK by other devices on the SMBus. The Hub does not stretch the SCLK.

4.3.6SMBus Timing

The SMBus Slave Interface complies with the SMBus AC Timing Specification. See the SMBus timing in the “Timing Diagram” section.

4.3.7Bus Reset Sequence

The SMBus Slave Interface resets and returns to the idle state upon a START field followed immediately by a STOP field.

4.3.8SMBus Alert Response Address

The SMBALERT# signal is not supported by the Hub.

4.3.8.1Undefined Registers

The registers shown in Table 4.1 are the defined registers in the Hub. Reads to undefined registers return 00h. Writes to undefined registers have no effect and do not return an error.

4.3.8.2Reserved Registers

Unless otherwise instructed, only a ‘0’ may be written to all reserved registers or bits.

4.4Default Configuration Option:

The SMSC Hub can be configured via its internal default configuration. (please see Section 4.2.1, "Internal Register Set (Common to EEPROM and SMBus)" for specific details on how to enable default configuration.)

Please refer to Table 4.1 for the internal default values that are loaded when this option is selected.

4.5Default Strapping Options:

The USB2512i can be configured via a combination of internal default values and pin strap options. Please see Table 3.1 and Table 3.2 for specific details on how to enable the default/pin-strap configuration option.

The strapping option pins only cover a limited sub-set of the configuration options. The internal default values will be used for the bits & registers that are not controlled by a strapping option pin. Please refer to Table 4.1 for the internal default values that are loaded when this option is selected.

4.6Reset

There are two different resets that the Hub experiences. One is a hardware reset (either from the internal POR reset circuit or via the RESET_N pin) and the second is a USB Bus Reset.

4.6.1Internal POR Hardware Reset

All reset timing parameters are guaranteed by design.

SMSC USB2512i

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Revision 1.92 (11-28-07)

 

DATASHEET