AN2540 - Application note

Implementing the EEPROM emulation

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Figure 3.

Sector swap scheme: Sector0 erased

3.2.2

EEPROM software description

This section describes the driver implemented for EEPROM emulation using the

STR91xFxx Flash library provided by STMicroelectronics.

A demonstration program is also supplied to demonstrate and test the EEPROM Emulation

driver using the three variables A, B and C already defined.

The project contains three source files in addition to the FMI library source files:

●

eeprom.c: containing C code for the following routines:

EepromFormat()

WriteVariable()

ReadVariable()

FindValidSector()

WriteVerifyVariableFull()

EepromSectorTransfer()

●

eeprom.h: Containing the routines’ prototypes and some declarations.

●

main.c: This application program is an example using the routines described in

eeprom.c.

A(t) values

B(t) values

C(t) values

0x0000 0000

0x0000 1FFF

A(t0)

B(t0)

C(t0)

Sector0 Erased

Sector1 Header

A(t) values

B(t) values

C(t) values

0x0000 2000

0x0000 3FFF

Sector1

Update

Update

Update

Sector swap

(Erase one when using the other)

A(t0 + tA)

A(t0 + n × tA)

B(t0 + m × tB)

C(t0 + p × tC)

Sector0 Header

0

A(t

+ (n + 1) × tA)

B(t0 + m × tB)

0

C(t + p × tC)

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