20 SBC347A 3U VPX Single Board Computer
Publication No. 500-9300527837-000 Rev. A.0
3.2 Inspection
The SBC347A is shipped from the factory with no jumpers fitted.
3.3 Link Descriptions
NOTES
Ordinary operation requires no jumpers to be fitted.
Software can read the state of the links from the FPGA.
Additional jumper link functions are provided by an onboard EEPROM DIP switch device.
See
Section 5.14.2 EEPROM DIP Switch
on
.
TIP
If you are about to install your board and power up for the first time, leaving your board in the
default configuration will enable board operation to be proven before tackling any further
configuration issues.
3.3.1 Recovery Boot Link (P3)
This link allows user selection of the SPI Flash device from which the SBC347A
boots, as follows:
In normal operation, a jumper is not fitted on this link, and the SBC347A boots
from the Main device.
The factory-programmed Recovery device is for use if the Main device is
corrupted. Booting from the Recovery device puts the SBC347A into Recovery
mode. Here, onboard configuration EEPROMs are disabled, allowing devices to
come up using default strapping.
3.3.2 Configuration EEPROM Write Enable Link (P4)
Nonvolatile configuration EEPROM devices on the board are used to configure
the initial state of the PCIe switch and memory serial presence detect (SPD) data.
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.
The VPX backplane Nonvolatile Memory Read Only (NVMRO) signal (on the
pin A4) must
also be set inactive low before any configuration EEPROM can be written.
Table 3-1 P3 Link Setting
Setting Meaning
In
SBC347A boots from Recovery device
Out
SBC347A boots from Main device
(default)
Table 3-2 P4 Link Setting
Setting Meaning
In
Configuration EEPROM hardware write protection is disabled
Out
Configuration EEPROM hardware write protection is enabled
(default)