[牛人杂谈] 使用Data Flash模拟EEPROM

/**

* [url=home.php?mod=space&uid=247401]@brief[/url] Initial Data Flash as EEPROM.

* @param[in] data_size: The amount of user's data, unit in byte. The maximun amount is

 128.

* @param[in] use_pages: The amount of page which user want to use.

* @retval Err_OverPageSize: The amount of user's data is over than the maximun amount.

* @retval Err_OverPageAmount: The amount of page which user want to use is over than

 the maximun amount.

* @retval 0: Success

*/

uint32_t Init_EEPROM(uint32_t data_amount, uint32_t use_pages)

{

uint32_t i;

/* The amount of data includes 1 byte address and 1 byte data */

Amount_of_Data = data_amount;

/* The amount of page which user want to use */

Amount_Pages = use_pages;

/* Check setting is valid or not */

/* The amount of user's data is more than the maximun amount or not */

if(Amount_of_Data > Max_Amount_of_Data)

return Err_OverAmountData;

/* For M051 Series, the max. amount of Data Flash pages is 8 */

if(Amount_Pages > 8)

return Err_OverPageAmount;

/* Init SRAM for data */

Written_Data = (uint8_t *)malloc(sizeof(uint8_t) * Amount_of_Data);

/* Fill initial data 0xFF*/

for(i = 0; i < Amount_of_Data; i++)

{

Written_Data[i] = 0xFF;

}

return 0;

}

/**

* @brief Search which page has valid data and where is current cursor for the next

data to write.

*/

void Search_Valid_Page(void)

{

uint32_t i, temp;

uint8_t addr, data;

uint16_t *Page_Status_ptr;

/* Enable FMC ISP function */

FMC_Enable();

/* Set information of each pages to Page_Status */

Page_Status_ptr = (uint16_t *)malloc(sizeof(uint16_t) * Amount_Pages);

for(i = 0; i < Amount_Pages; i++)

{

Page_Status_ptr[i] = (uint16_t)FMC_Read(DataFlash_BaseAddr +

(FMC_FLASH_PAGE_SIZE * i));

}

/* Search which page has valid data */

for(i = 0; i < Amount_Pages; i++)

{

if(Page_Status_ptr[i] != Status_Unwritten)

Current_Valid_Page = i;

}

/* If Data Flash is used for first time, set counter = 0 */

if(Page_Status_ptr[Current_Valid_Page] == Status_Unwritten)

{

/* Set counter = 0 */

FMC_Write(DataFlash_BaseAddr + (FMC_FLASH_PAGE_SIZE *

Current_Valid_Page), 0xFFFF0000);

/* Set cursor to current Data Flash address */

Current_Cursor = 2;

}

else

{

/* Search where is current cursor for the next data to write and get the

data has been written */

/* Check even value */

temp = FMC_Read(DataFlash_BaseAddr + (FMC_FLASH_PAGE_SIZE *

Current_Valid_Page));

addr = (temp & Even_Addr_Mask) >> Even_Addr_Pos;

data = (temp & Even_Data_Mask) >> Even_Data_Pos;

/* Check Address is 0xFF (un-written) of not */

if(addr == 0xFF)

{

/* If Address is 0xFF, then set cursor to current Data Flash

address */

Current_Cursor = 2;

}

else

{

/* Copy the address and data to SRAM */

Written_Data[addr] = data;

/* Check the whole Data Flash */

for(i = 4; i < FMC_FLASH_PAGE_SIZE; i += 4)

{

/* Check odd value */

temp = FMC_Read(DataFlash_BaseAddr +

(FMC_FLASH_PAGE_SIZE * Current_Valid_Page) + i);

addr = (temp & Odd_Addr_Mask) >> Odd_Addr_Pos;

data = (temp & Odd_Data_Mask) >> Odd_Data_Pos;

/* Check Address is 0xFF (un-written) of not */

if(addr == 0xFF)

{

/* If Address is 0xFF, then set cursor to

current Data Flash address */

Current_Cursor = i;

break;

}

else

{

/* Copy the address and data to SRAM */

Written_Data[addr] = data;

}

/* Check even value */

addr = (temp & Even_Addr_Mask) >> Even_Addr_Pos;

data = (temp & Even_Data_Mask) >> Even_Data_Pos;

/* Check Address is 0xFF (un-written) of not */

if(addr == 0xFF)

{

/* If Address is 0xFF, then set cursor to

current Data Flash address */

Current_Cursor = i + 2;

break;

}

else

{

/* Copy the address and data to SRAM */

Written_Data[addr] = data;

}

}

}

}

}