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RL78 Family

Chapter 2

EEPROM Emulation

Type 01 EEPROM Emulation Library Pack02

R01US0068EJ0100

Rev.1.00

Page 9 of 53

Mar. 28, 2014

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.)

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