R01US0068EJ0100 Datasheet, PDF (9/56 Pages) Renesas Technology Corp – EEPROM Emulation Library

RL78 Family
Type 01 EEPROM Emulation Library Pack02
Chapter 2 EEPROM Emulation
Chapter 2 EEPROM Emulation
2. 1 Specifications of EEPROM Emulation
By calling the EEL function provided by the EEL from a user-created program, use is possible without the
awareness of data flash memory operations.
For the EEL, a one-bye identifier (data ID: 1 to 64) is assigned by the user for each data item, and reading and
writing using any unit from 1 to 255 bytes are possible on an assigned identifier basis.(The EEL can handle up to 64
identifiers.)
Note that three or more continuous block area of data flash memory (recommended) ^Note are used to store the
data. These blocks are called EEL blocks. Data written by EEPROM emulation is divided into reference data and
user-specified data, and the reference data is written to the target blocks from the lower block address, while the
user data is written from the higher block address.
Note: At least two blocks are necessary for EEPROM emulation. When two blocks are specified, if a write error
occurs even once, only reading of normally written data is possible but writing is no longer possible. After
that, the two target blocks must be formatted when the EEL is used to write data. Written data is erased
completely. Since a contingency (such as voltage drop) may occur in the system, we recommend that you
specify at least three blocks.
2. 2 Outline of Function
The EEL provides basic read/write functions having the following features.
• Up to 64 data items settable
• A data size of 1 to 255 bytes settable
• Supporting the back ground operation (BGO)
• Consumption of memory for management data
(10 bytes per EEL block and 2 bytes per EEL block write data)
• Reset resistance (EEL_CMD_WRITE, EEL_CMD_REFRESH)
• Block rotation (averaging data flash use frequency)
Renesas Electronics also provides RL78 EEPROM Emulation Library Pack 01 (EEL Pack01) as another EEL.
EEL consumes smaller amount of resource than EEL Pack01. Other functional differences are listed in the table
below. (For details of functions, see the RL78 Microcontroller EEPROM Emulation Library Pack 01 user’s manual
R01US0054EJ0102.)
R01US0068EJ0100 Rev.1.00
Mar. 28, 2014
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