22 SBC329 3U VPX Single Board Computer
Publication No. SBC329-HRM/1
3.3.2
Configuration EEPROM Write Enable Link (P6)
This link provides control over the hardware protection of the following non-volatile
configuration EEPROM devices:
PCIe Switch Configuration EEPROM
ETH1 and ETH2 Configuration EEPROM
SPD EEPROM
EEPROM DIP Switch
These are used to configure the initial state of the PCIe switch, Ethernet interfaces,
memory controller and other configuration options respectively.
Table 3-2 P6 Link Setting
Setting Meaning
In
Software can change EEPROM write protection
Out
EEPROM write protection is locked (default)
NOTES
This link controls the
hardware
write protection of the configuration EEPROM devices. Some
devices also require software write protection, which must be provided by the operating system
or the BIOS (see the
The VPX backplane Non-Volatile Memory Read Only (NVMRO) signal (on
must also be set inactive low before any configuration EEPROM can be written.
For further clarification, the following table shows interaction between P6 and
NVMRO for the above devices:
Device
NVMRO P6 Setting Access Mode
PCIe Switch Configuration EEPROM,
ETH1 and ETH2 Configuration EEPROM,
SPD EEPROM
Low (0) In
Software changeable
Low (0) Out
Frozen
High (1) In or out
Frozen
EEPROM DIP Switch
Low (0) In
Write enabled
Low (0) Out
Read only
High (1) In or out
Read only