GE PACSystems RXi User Manual

Chapter 5. CPU OperationGFK-2816F August 2015 835.6 Flash Memory OperationThe CPU stores the current configuration and application in user memory. You can also storethis data into non-volatile flash memory. The PACSystems CPU provides enough flashmemory to hold all of user space, all reference tables that aren't counted against user space,and any overhead required. For details on which items count against user memory space,refer to Appendix C.By default, the CPU reads program logic and configuration, and reference table data fromuser memory at power-up. However, logic/configuration and reference tables can each beconfigured to always read from flash or conditionally read from flash. To configure theseparameters in the programming software, select the CPU’s Settings tab in HardwareConfiguration.If logic/configuration and/or reference tables are configured for conditional power-up fromflash, these items are restored from flash to user memory when user memory is corrupted ornot preserved. When user memory is preserved, no flash operation occurs.If logic/configuration and/or reference tables are configured to always power up from flash,these items are restored from flash to user memory regardless of the state of the usermemory.Note: If any component (logic/configuration or reference tables) is read from flash,OEM-mode and passwords are also read from flash.In addition to configuring where the CPU obtains logic, configuration, and data duringpower-up, the programming software provides the following flash operations:■ Write a copy of the current configuration, application program, and reference tables(excluding overrides) to flash memory. Note that a write-to-flash operation causes allcomponents to be stored to flash.■ Read a previously stored configuration and application program, and/or reference tablevalues from flash into user memory.■ Verify that flash and user memory contain identical data.■ Clear flash contents.Flash read and write operations copy the contents of flash memory or user memory asindividual files. The programming software displays the progress of the copy operation andallows you to cancel a flash read or write operation during the copy process instead of waitingfor the entire transfer process to complete. The entire user memory image must besuccessfully transferred for the flash copy to be considered successful. If an entirewrite-to-flash transfer is not completed due to canceling, power cycle, or some otherintervention, the CPU will clear flash memory. Similarly, if a read-from-flash transfer isinterrupted, user memory will be cleared.