
APPENDIX
B–63465EN/01
C. BOOT SYSTEM
127
CAUTION
Action to be taken when an SRAM parity error is detected
during backup of SRAM in the boot system
The SRAM area of each Digital Servo Adapter shipped flash
ROM the factory is cleared and is free of parity errors.
However, shock applied to the Digital Servo Adapter during
transportation may cause a parity error in the SRAM area.
A parity error may also occur in the SRAM area when the
Digital Servo Adapter was kept switched off for one year or
longer, and the battery has been exhausted. If a parity error
occurs in the SRAM area, the data held in the SRAM area
is not guaranteed. However, the Digital Servo Adapter does
not always use the entire SRAM area. A parity error is not
detected by hardware unless the part containing the error
is read. Therefore, if a parity error occurs in an area not
accessed by the Digital Servo Adapter, the Digital Servo
Adapter may operate normally. The SRAM backup function
of the boot system reads the entire SRAM area. So, a parity
error may occur in the middle of backup operation even
when the Digital Servo Adapter has operated normally. In
this case, the SRAM data of the Digital Servo Adapter is not
guaranteed, and the data cannot be backed up using the
SRAM backup function of the boot system. Nevertheless,
the Digital Servo Adapter may operate normally. So, it is
recommended that necessary data be backed up using the
Handy File, data all clear operation be performed, then the
backed up data be restored in the Digital Servo Adapter.
Once all clear operation is performed, the parity error can be
removed. Then, the SRAM backup function of the boot
system can be used.