Vital Product Data (Vpd) - Realtek RTL8169 Manual

8.8 Vital Product Data (VPD)

Bit 31 of the VPD is used to issue VPD read/write command and is also a flag used to indicate whether the transfer of data
between the VPD data register and the 93C46/93C56 is completed or not.
1. Write VPD register: (write data to 93C46/93C56)
Set the flag bit to 1 at the same time the VPD address is written to write VPD data to EEPROM. When the flag bit is reset
to 0 by the RTL8169, the VPD data (4 bytes per VPD access) has been transferred from the VPD data register to
EEPROM.
2. Read VPD register: (read data from 93C46/93C56)
Reset the flag bit to 0 at the same time the VPD address is written to retrieve VPD data from EEPROM. When the flag bit
is set to 1 by the RTL8169, the VPD data (4 bytes per VPD access) has been transferred from EEPROM to the VPD data
register.
- Please refer to PCI Configuration Space Table in Section 8.1 and PCI 2.2 Specifications for further information.
- The VPD address does not have to be a DWORD-aligned address as defined in the PCI 2.2 Specifications, but the
VPD data is always consecutive 4-byte data starting from the VPD address specified.
- Realtek reserves offset 40h to 7Fh in EEPROM mainly for VPD data to be stored.
- The VPD function of the RTL8169 is designed to be able to access the full range of the EEPROM (either 93C46 or
93C56).
2002/03/27
49
RTL8169
Rev.1.21