R01US0079ED0103 Datasheet, PDF (63/66 Pages) Renesas Technology Corp – RENESAS 32-Bit MCU

Data Flash Access Library - Type T01, European Release
Cautions
interrupt & exception disable, DMA,... .The sample application provides examples on how
to disable and restore interrupts and exceptions using the callback routines.
9. Interrupted flash operations:
In case of Flash modification operation (Erase / Write) interruption, the electrical conditions of the
affected Flash range (Flash block on erase, Flash write unit on Write) get undefined. It is
impossible to give a statement on the read value after the interruption. Furthermore, the resulting
read value is not reliable; the electrical margin for the specified data retention may not be given.
In such case, erase and re-write the affected Flash block(s) to ensure data integrity and retention.
10. Write operation:
Before executing a write operation, please make sure the given address range is erased.
11. Reading Data Flash:
Data Flash on RH850 devices is made with differential cells for storage. This means that reading
erased Data Flash areas directly (bypassing FDL) will produce undefined data with a tendency to
the previously written data and it will most probably cause ECC error exceptions. To avoid this
exceptions use R_FDL_CMD_READ command.
DMA transfers from Data Flash are permitted, but need to be synchronized with the FDL.
During command execution Data Flash is not available. Any direct read during command
execution will result in invalid data therefore it must be avoided.
12. Dual operation:
It is not possible to modify the Code Flash in parallel to a modification of the Data Flash or vice
versa due to shared hardware resources.
13. Reusing the request command:
Do not change the content of the request structure while an FDL command is operating because
the library may crash or data loss can occur. Multiple requests, each using different request
structures, do not have these adverse effects.
14. Workload and supervision:
It is recommended to supervise the FDL operations and functions execution by timeout
supervision (e.g. timer, counter, watchdog, etc.). In addition, the user of the library should
evaluate the time necessary to perform a certain operation and divide long lasting operations to
meet real-time system specifications.
15. Suspend and Stand-by nesting:
It is not always possible to nest suspend and/or stand-by. E.g.:
 Any operation ► suspend ► suspend – is not possible.
 Any operation ► stand-by ► stand-by – is not possible.
 Any operation ► stand-by ► suspend – is not possible.
 Write or Erase ► suspend ► Erase operation – is not possible
 Any operation ► suspend ► other operation ► suspend – is not possible
 Write operation ► suspend ► other Write operation – is not possible
It is recommended to avoid nesting as much as possible.
16. Stand-by:
Do not continue FDL functions execution or start execution of any other function than
R_FDL_GetVersionString, R_FDL_WakeUp or R_FDL_Init when the library is in stand-by
mode.
17. Data alignment:
Data Flash blocks are aligned to 64 bytes and Data Flash words are aligned to 4 bytes.
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User Manual