R01US0079ED0103 Datasheet, PDF (62/66 Pages) Renesas Technology Corp – RENESAS 32-Bit MCU

Data Flash Access Library - Type T01, European Release
Cautions
Chapter 6 Cautions
Before starting the development of an application using the FDL, please carefully read and understand
the following cautions:
1. CPU operating frequency configuration:
Correct frequency configuration is essential for Flash programming quality and stability. Wrong
configuration could lead to loss of data retention or Flash operation fail.
The limits for CPU frequency are device dependent. Please consult Device Manual for correct
range.
If the CPU frequency is a fractional value, round up the value to the nearest integer.
Do not change power mode (voltage or CPU clock) while FDL is performing a Data Flash
operation. If power mode must change the user can:
 put current operation into stand-by mode and wait until hardware conditions are restored
 wait until operations are no longer busy or
 reinitialize the library with proper CPU frequency value
2. CPU mode:
The initialization function R_FDL_Init must be executed in CPU supervisor mode (register bit
PSW.UM = 0).
3. Function re-entrancy:
All functions are not re-entrant. So, re-entrant calls of any FDL function must be avoided.
4. Task switch, context change, synchronization between functions:
Each function depends on global available information and is able to modify this information. In
order to avoid synchronization problems, it is necessary that at any time only one FDL function is
executed. So, it is not allowed to start an FDL function, then switch to another task context and
execute another FDL function while the last one has not finished.
5. Entering power save (stand-by) mode:
Entering power save mode is not allowed at all during on-going Data Flash operations. Use
R_FDL_StandBy or wait until operations are no longer busy.
6. Different power save (stand-by) modes:
Other power save modes than HALT will result in Flash hardware internal data loss. So, don’t
enter power save modes except HALT when further FDL operations are intended after wake-up.
If entering other modes, the FDL need to be re-initialized by R_FDL_Init.
7. Initialization:
The FDL library initialization by means of calling R_FDL_Init must be performed before calling
most of the library functions. Exception is R_FDL_GetVersionString function that can be
called anytime.
8. Critical Section handling:
The R_FDL_Init function temporarily disables Code Flash. During this time, since the Code
Flash is not available, the library is executing code from internal RAM (allocated space on stack).
Please ensure that:
 Code execution is done from other locations (e.g. internal RAM).
 No access to Code Flash is allowed, e.g. by jump to interrupt/exception functions, direct
Code Flash Read/Execution from the CPU, DMA accesses to Code Flash. The user can
configure the provided callback macro functions in fdl_cfg.h. , in order to handle e.g.
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User Manual