6
CONFIGURATION OPTIONS
If ROMEN is tied high, then the internal ROM code is used for operation. If low, then an external memory on the FD
bus is used for operational code.
If the internal ROM is used, OPT3 must be tied high and OPT[2:0] must be tied low through a resistor. In this mode,
an external serial EEPROM is used to store the OEM’s USB assigned VID, their PID, their Product String, and the
options for the particular drive connected to the USB97CFDC2-01.
The data in the EEPROM is organized as follows:
Note: If the data is not of the specified length, then fill the length with zeros, following the data.
DEVICE DESCRIPTOR - 18 BYTES
For a device with a VID/PID of 0424/0dc, the Device Descriptor looks like the one below. (Note that the data is
separated by carriage returns in the “EEPROM.DAT” file. It is displayed here on a single line for clarity’s sake.) The
VID/PID occupy byte position 9 through 12.
12 0110 01 00 00 00 40 24 04 dc 0f 22 01 01 02 00 01
The data in bold are the VID and PID information. Note that the lo and the hi bytes are swapped, as in VendorLo,
VendorHi, ProductLo and ProductHi.
LANGUAGE STRING - 4 BYTES
String: 0409 (The language code for English)
EEPROM.DAT: 04 03 09 04 (1st byte is the length, then the string ID, followed by the language ID in little endian.)
MANUFACTURER STRING – 60 BYTES (UNICODE FORMAT)
Example String: SMSC
EEPROM.DAT: 3c 03 53 00 4d 00 53 00 43 00 … 00 (1st byte is the length, followed by the string ID and the Unicode
string itself in little endian.)
PRODUCT STRING – 60 BYTES (UNICODE FORMAT)
Example String: USB FDC
EEPROM.DAT: 3c 03 55 00 53 00 42 00 20 00 46 00 44 00 43 00 … 00 (Again the 1st byte is the length, followed by
the string ID and the Unicode string itself in little endian.)
SERIAL NUMBER STRING – 60 BYTES (UNICODE FORMAT)
String: None
EEPROM.DAT: 3c 03 4e 00 6f 00 6e 00 65 00 … 00 (Again the 1st byte is the length, followed by the string ID and the
Unicode string itself in little endian.)
INQUIRY DATA (IN RESPONSE TO A UFI_INQUIRY REQUEST) - 36 BYTES
Bytes 0 – 7: The values for the 1st 8 bytes of the inquiry data come from Table 10 of the USB Mass Storage Class
UFI Command Specification. For the USB floppy device, those bytes should be 00 80 00 01 1f 00 00 00. These bytes
do not change.
Bytes 8 – 15: Vendor Information (Example: SMSC)
EEPROM.DAT: 53 4d 53 43 20
Bytes 16 – 31: Product Identification (Example: USB FDD)
EEPROM.DAT: 55 53 42 20 46 44 44 20
Bytes 32 – 35: Product Revision Level (Example: 2.00)
EEPROM.DAT: 32 2e 30 30
SMSC DS – USB97CFDC2-01
Page 12
Rev. 02-27-07
DATASHEET
SMSC [ SMSC CORPORATION ]
