R01US0068EJ0100 Datasheet, PDF (11/56 Pages) Renesas Technology Corp – EEPROM Emulation Library

RL78 Family
EEPROM Emulation Library Pack02
2. 3 EEL architecture
Chapter 2 EEPROM Emulation
This chapter describes the EEL architecture required for the user to rewrite data flash (the EEL pool) by using the
EEL.
2. 3. 1 System Structure
The EEL offers interface for accessing the data flash area defined by the user. The arrows shown in the figure 2-1
below indicate the flow of processing.
Figure 2-1 System Structure
ユーザ・プログラム
Code Flash
User Program
Before using the EEL, the FDL must
be initialized.
(FDL_Init and FDL_Open function)
EEL
FDL
Data Flash
(EEL Pool)
2. 3. 2 EEL Pool
The EEL pool is a user-defined data flash area that is accessible by the EEL. The user program can access the
data flash only by using this EEL pool in the data flash via the EEL. The EEL pool size must be specified with the
number of blocks in the data flash of the target device. For the procedure to specify the number of blocks, see
section 4.3, Initial Values to be set by User.
The EEL pool is divided into 1024-byte blocks. Each block has a state which indicates the current usage of the
block.
State
Active
Invalid
Excluded
Description
Only a single EEL block is active at a time to store defined data. The active block circulates in
data flash blocks allocated in the EEL pool.
No data is stored in invalid blocks. EEL blocks are marked as invalid by the EEL or become
invalid in the case of erasure blocks.
If functional operation failed and possibility of a data flash failure is clarified, the EEL excludes
the relevant block and the block is no longer used for EEPROM emulation.
R01US0068EJ0100 Rev.1.00
Mar. 28, 2014
Page 11 of 53