R01US0068EJ0100 Datasheet, PDF (25/56 Pages) Renesas Technology Corp – EEPROM Emulation Library

RL78 Family
EEPROM Emulation Library Pack02
Chapter 4 Using EEPROM Emulation
Chapter 4 Using EEPROM Emulation
EEPROM emulation can store a maximum of 64 ^Note data items each consisting of 1 to 255 bytes in the flash
memory by using three or more blocks (recommended) of flash memory.
EEPROM emulation can be executed by incorporating the EEL into a user-created program and executing that
program.
Note: For details about the number of user data items that can be stored, see 4.2 Number of stored user data
items and total user data size.
4.1 Caution Points
EEPROM emulation is achieved by using a feature for manipulating the on-board microcontroller data flash
memory. Therefore, it is necessary to note the following
Table 4-1 Points for Caution (1/2)
No
Caution Points
1 All EEL codes and constants must be placed in the same 64-Kbyte flash block.
2 Initialization by the FDL_Init function must be performed before the FDL_Open, FDL_Close, or any EEL
function is executed.
3 The EEL must be initialized by the EEL_Init function before any EEL function is executed.
4 ^{The data flash memory cannot be read during data flash memory operation by the EEL.}
5 Do not execute STOP mode or HALT mode processing while the EEPROM emulation is being used.
If it is necessary to execute STOP mode or HALT mode processing, be sure to execute all of the
processing up to and including the EEL_Close function and FDL_Close function to finish EEPROM
emulation.
6 _{The watchdog timer does not stop during the execution of the EEL.}
7 The request structure (eel_request_t) must be placed at an even address.
8 Do not destroy the request structure (eel_request_t) during command execution.
9 Initialize the argument (RAM) that is used by the EEPROM emulation library function. When not initialized,
a RAM parity error is detected and the RL78 microcontroller might be reset. For a RAM parity error, refer
to the user’s manual of the target RL78 microcontroller.
10 All members of the request structure (eel_request_t) must be initialized once before a command is
executed. If any unused member exists in the request structure (eel_request_t), set a desired value for the
member. If any member is not initialized, the RL78 microcontroller may be reset due to a RAM parity error.
For details, see the User’s Manual: Hardware for the RL78 microcontroller in use.
11 The EEL does not support multitask execution. Do not execute the EEL functions during interrupt
processing.
R01US0068EJ0100 Rev.1.00
Mar. 28, 2014
Page 25 of 53