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EEPROM Interface

Though the FT232BQ will work without the optional EEPROM, an external 93C46 (93C56 or 93C66) EEPROM

can be used to customise the USB VID, PID, Serial Number, Product Description Strings and Power Descriptor

value of the FT232BQ for OEM applications. Other parameters controlled by the EEPROM include Remote

Wake Up, Isochronous Transfer Mode, Soft Pull Down on Power-Off and USB 2.0 descriptor modes.

The EEPROM should be a 16 bit wide configuration such as a MicroChip 93LC46B or equivalent capable of a

1Mb/s clock rate at VCC = 4.35V to 5.25V. The EEPROM is programmable-on board over USB using a utility

available from FTDI’s web site (http://www.ftdichip.com). This allows a blank part to be soldered onto the PCB

and programmed as part of the manufacturing and test process.

If no EEPROM is connected (or the EEPROM is blank), the FT232BQ will use its built-in default VID, PID

Product Description and Power Descriptor Value. In this case, the device will not have a serial number as part

of the USB descriptor.