What are Subsystem Device ID and Vendor ID?
The Subsystem Device ID and Vendor ID registers are part of the PCI Configuration registers. These are usually used when a PCI device is used as part of an add-in card.
For example, if you are using the CY7C09449PV PCI Dual-port on an add-in board that your company manufactures, the PCI dual-port itself has the Vendor ID and Device ID provided by Infineon Semiconductor. However, the subsystem Vendor ID and Device ID would be specific to your company. This is used to uniquely identify the add-in card or sybsystem that the PCI-DP resides within. Using these two registers, your computer can then differentiate between two different boards made by different companies that may both contain the CY7C09449PV chip. Otherwise, your computer would not know which drivers to use with which board.
What are Vendor ID and Subsystem Device ID assigned to?
We do not assign the Subsystem Vendor ID. This is a Vendor ID assigned to your company by the PCI-SIG (Special Interest Group). The PCI-SIG is the only body officially licensed to give out IDs. You need to be a member of PCI-SIG to request your own ID. Information about joining PCI-SIG is available here: http://www.pcisig.com. The Subsystem Device ID is then whatever you choose for that specific board.
Where to find the Subsystem ID number?
To load your subsystem ID numbers into the PCI Configuration registers within the CY7C09449PV, you can use the boot EEPROM. Just load the EEPROM with your ID numbers into address 0x4C. When you restart the PCI-DP, it will automatically load these values into the configuration register.
If you want to load your subsystem ID numbers into the PCI Configuration registers, you have to review the articles 'Accessing the EEPROM' and 'Using a Serial EEPROM' for more information.
