Implementing the EEPROM emulation

AN2540 - Application note

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At the beginning, the function determines the active sector which is the sector to be

transferred from. The new sector header field is defined and written (new sector status is

RECEIVE_DATA given that it is in the process of receiving data). When the data transfer is

complete, the new sector header is marked VALID_SECTOR and the old one

TRANSFER_COMPLETE. At the end, the old sector is erased.

– User-configured emulated EEPROM size.

– The number of Flash program/erase cycles used can be minimized by permanently

allocating a large memory space to the most frequently updated non-volatile data

variables.

– ReadVariable and WriteVariable functions to access variables.

– The whole available memory space is used to store data: no need for virtual

addresses.

– Fast read access to any variable since this simply implies going to the corresponding

allocated memory space.

– Interrupt servicing during program/erase is possible.

Table 7.

EepromSectorTransfer

Function Name

EepromSectorTransfer

Function Prototype

u8 EepromSectorTransfer(u8 index, u32 *T, u16 data);

Behavior Description

It transfers the most recent data (Last variable updates) plus the new

data from a full sector to an empty one.

Input Parameter

– index: variable identifier (0, 1, 2...)

– T: variable array

– data: 16-bit data to be written

Return Parameter

Returns 1 on success or error code on failure

Called functions

FindValidSector,FMI_WriteHalfWord, WriteVerifyVariableFull,

ReadVariable, FMI_EraseSector.