R01US0068EJ0100 Datasheet, PDF (12/56 Pages) Renesas Technology Corp – EEPROM Emulation Library

RL78 Family
EEPROM Emulation Library Pack02
Chapter 2 EEPROM Emulation
Figure 2-2 shows an exemplary pool configuration for a device with 8 KB data flash.
When no writable area is remaining in the active block (block 1 in the example) and data can no longer be stored
(failure in write command), a new active block is selected in a cyclic manner and the current valid data set is copied
to this new active block. This process is referred to as refresh. After the EEL_CMD_REFRESH command is
executed, the previous active block becomes invalid and only a single active block exists. Excluded blocks (like
block 7 in the example) are ignored during this process and not considered as candidates for the selection of the
next active block.
Figure 2-2 EEL pool structure
Data Flash Memory
physical
block
0
physical
block
1
physical
block
2
physical
block
3
physical
block
4
physical
block
5
physical
block
6
physical
block
7
EEL pool
EEL
block
0
I
EEL
block
1
A
EEL
block
2
I
EEL
block
3
I
EEL
block
4
I
EEL
block
5
I
EEL
block
6
I
EEL
block
7
X
A active block
I invalid block
X excluded block
The overall life cycle of a block in the EEL pool is shown in Figure 2-3. During normal operation, the block
switches between active and invalid state. When an error occurs during an access to the EEL block, the error EEL
block is marked as excluded. This block will not enter the lifecycle again. However, the user can try to reanimate the
block by a format of the complete pool which also erases all existing data content.
Figure 2-3 Life cycle of an EEL block
invalid
block
I
R01US0068EJ0100 Rev.1.00
Mar. 28, 2014
active
block
A
format
excluded
block
X
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