Datasheet

USB Registers

SLLS519H—January 2010TUSB3410, TUSB3410I

Clock Output Control

Bit 2 (CLKOUTEN) in the MODECNFG register enables or disables the clock output at the CLKOUT terminal

of the TUSB3410. The power up default of CLKOUT is disabled. Firmware can write a 1 to enable the clock

output if needed.

Bit 3 (CLKSLCT) in the MODECNFG register selects the output clock source from either a fixed 3.556-MHz

free-running clock or the UART BaudOut clock.

5.6 Vendor ID/Product ID

USB−IF and Microsoft WHQL certification requires that end equipment makers use their own unique vendor

ID and product ID for each product (model). OEMs cannot use silicon vendor’s (for instance, TI’s default)

VID/PID in their end products. A unique VID/PID combination will avoid potential driver conflicts and enable

logo certification. See www.usb.org for more information.

5.7 SERNUM7: Device Serial Number Register (Byte 7) (Addr:FFEFh)

Each TUSB3410 device has a unique 64-bit serial die id number, which is generated during manufacturing.

The die id is incremented sequentially, however there is no assurance that numbers will not be skipped. The

device serial number registers mirror this unique 64-bit serial die id value.

After power-up reset, this read-only register (SERNUM7) contains the most significant byte (byte 7) of the

complete 64-bit device serial number. This register cannot be reset.

765 4 32 1 0

D63

D62 D61 D60 D59 D58 D57 D56

R/O R/O R/O R/O R/O R/O R/O R/O

BIT

NAME RESET FUNCTION

7−0 D[63:56] Device serial number byte 7 value Device serial number byte 7 value

Procedure to load device serial number value in shared RAM:

• After power-up reset, the boot code copies the predefined USB descriptors to shared RAM. As a result,

the default serial number hard-coded in the boot code (0x00 hex) is copied to the shared RAM data space.

• The boot code checks to see if an EEPROM is present on the I

C port. If an EEPROM is present and

contains a valid device serial number as part of the USB device descriptor information stored in EEPROM,

then the boot code overwrites the serial number value stored in shared RAM with the one found in

EEPROM. Otherwise, the device serial number value stored in shared RAM remains unchanged. If

firmware is stored in the EEPROM, then it is executed. This firmware can read the SERNUM7 through

SERNUM0 registers and overwrite the serial number stored in RAM or store a custom number in RAM.

• In summary, the serial number value in external EEPROM has the highest priority to be loaded into shared

RAM data space. The serial number value stored in shared RAM is used as part of the valid device

descriptor information during normal operation.