20 PPC11A 6U VME Single Board Computer
Publication No. PPC11A-HRM/1
2.3.2 NVRAM Write Enable Link (P15 Pins 5 and 6)
This link controls the write protection for the NVRAM device on the PPC11A. This
device holds firmware boot parameters as well as user data.
Table 2-2 P15 Pins 5 and 6 Jumper Function
Setting Meaning
Out
The NVRAM is write protected
In
The NVRAM is write enabled
NOTES
The EEPROM DIP switch also plays a part in configuring the NVRAM write protection.
The backplane NVM_WE~ signal has the same effect, when asserted low, as fitting a jumper on this link.
The signals are ORed in the FPGA, so either may be used.
2.3.3 Flash Protection Unlock Link (P15 Pins 7 and 8)
Fitting a jumper on this link allows software to access the password to enable the
Flash persistent sector protection (which remains unchanged following a reset or a
power-cycle) to be altered. See the
Not fitting a jumper on this link prevents software from altering any previously
configured sector protection.
Table 2-3 P15 Pins 7 and 8 Jumper Function
Setting Meaning
Out
Persistent sector protection cannot be altered
In
Persistent sector protection can be altered
NOTE
When selected, using
EEPROM DIP Switch 1 Register 1
, GPIO5 has the same effect, when asserted high, as
fitting a jumper on this link. The backplane FLASH_PW_UL~ signal has the same effect, when asserted low.
The signals are ORed in the FPGA, so any may be used.
2.3.4 Configuration Write Enable Link (P15 Pins 9 and 10)
This link controls the write protection of the on-board non-volatile configuration
EEPROM devices. These are used to configure the initial state of the processor and
PCIe switches or board configuration options controlled by software.
Table 2-4 P15 Pins 9 and 10 Jumper Function
Setting Meaning
Out
Configuration memory write-disabled
In
Configuration memory write-enabled