The following are the steps to integrate or enable AWE Flash File System. Make sure the flash device is fully erased for the first time before enabling AWE Flash File System.
Define the following macros corresponding to flash memory size in bytes, erasable block size and the start offset for the Flash File System. Make sure the start offset does not overlap with other applications usage. It is recommended to use the free space in the flash from the end. Following are the example macros of a 64MB flash device:
/* ---------------------------------------------------------------------- ** Specify flash memory available for flash file system ** ------------------------------------------------------------------- */ #define FLASH_MEMORY_SIZE_IN_BYTES 0x4000000 #define ERASEABLE_SECTOR_SIZE 0x10000 #define FILE_SYSTEM_START_OFFSET 0xB0000 #define SECTOR_ERASE_TIME_MS 400
Declare a global AWE Flash File System instance:
/** Flash file system instance */ AWEFlashFSInstance g_AWEFlashFSInstance;
Initialize global AWE Flash File System instance to zero:
// Setup the flash file system */ memset(&g_AWEFlashFSInstance, 0, sizeof(AWEFlashFSInstance) );
Initialize the callbacks for ‘cbInit’, ‘cbEraseSector’, ‘cbFlashWrite’ and ‘cbFlashRead’:
g_AWEFlashFSInstance.cbInit = &usrInitFlashFileSystem; g_AWEFlashFSInstance.cbEraseSector = &usrEraseFlashMemorySector; g_AWEFlashFSInstance.cbFlashWrite = &usrWriteFlashMemory; g_AWEFlashFSInstance.cbFlashRead = &usrReadFlashMemory;
Initialize flash memory size, erasable block size, start offset and block erase time:
g_AWEFlashFSInstance.flashSizeInBytes = FLASH_MEMORY_SIZE_IN_BYTES; g_AWEFlashFSInstance.flashErasableBlockSizeInBytes = ERASEABLE_SECTOR_SIZE; g_AWEFlashFSInstance.flashStartOffsetInBytes = FILE_SYSTEM_START_OFFSET; g_AWEFlashFSInstance.flashEraseTimeInMs = (INT32)((FLOAT32)((( (FLASH_MEMORY_SIZE_IN_BYTES - FILE_SYSTEM_START_OFFSET)/ ERASEABLE_SECTOR_SIZE)*SECTOR_ERASE_TIME_MS/1000) + 0.5f) + 5);
Initialize the Flash File System by calling awe_initFlashFS:
awe_initFlashFS(&g_AWEInstance, &g_AWEFlashFSInstance);
Assign pFlashFileSystem in AWE Instance to Flash File System instance:
g_AWEInstance.pFlashFileSystem = &g_AWEFlashFSInstance;
Define callback functions for ‘Init’, ‘Erase’, ‘Write’ and ‘Read’:
{ // Implement any flash specific initializations return 1; } // End usrInitFlashFileSystem ///----------------------------------------------------------------------------- /// @name BOOL usrReadFlashMemory(UINT32 nAddress, UINT32 * pBuffer, UINT32 nDWordsToRead) /// @brief Read 4-byte words from flash memory /// /// @param[in] UINT32 nAddress - address in flash to start reading /// @param[in] UINT32 *pBuffer - buffer to read into /// @param[in] UINT32 nDWordsToRead - number of 4-bytes elements to read /// /// @retval SUCCESS - read succeeded /// @retval FAILURE - read failed ///----------------------------------------------------------------------------- BOOL usrReadFlashMemory(UINT32 nAddress, UINT32 * pBuffer, UINT32 nDWordsToRead) { BOOL bSuccess = 0; // Check for the count zero and skip remaining if(nDWordsToRead == 0) return 1; // Flash specific read implementation } // End usrReadFlashMemory ///----------------------------------------------------------------------------- /// @name BOOL usrWriteFlashMemory(UINT32 nAddress, UINT32 * pBuffer, UINT32 nDWordsToWrite) /// @brief Write 4-byte words to flash memory /// /// @param[in] UINT32 nAddress - address in flash to start writing /// @param[in] UINT32 * pBuffer - buffer to write into /// @param[in] UINT32 nDWordsToWrite - number of 4-bytes elements to write /// /// @retval SUCCESS - write succeeded /// @retval FAILURE - write failed ///----------------------------------------------------------------------------- BOOL usrWriteFlashMemory(UINT32 nAddress, UINT32 * pBuffer, UINT32 nDWordsToWrite) { BOOL bSuccess = 0; // Check for the count zero and skip remaining if(nDWordsToWrite == 0) return 1; // Flash device write specific implementation } // End usrWriteFlashMemory ///----------------------------------------------------------------------------- /// @name BOOL usrEraseFlashSector(UINT32 nStartingAddress, UINT32 nNumberOfSectors) /// @brief Erase flash memory starting at address for number of sectors /// /// @param[in] UINT32 nStartingAddress - address in flash to start erasing /// @param[in] UINT32 nNumberOfSectors - number of flash memory sectors to erase /// /// @retval SUCCESS - erase succeeded /// @retval FAILURE - erase failed ///----------------------------------------------------------------------------- //AWE_OPTIMIZE_FOR_SPEED BOOL usrEraseFlashSector(UINT32 nStartingAddress, UINT32 nNumberOfSectors) { UINT32 nSectorAddress, index, nSector; ERROR_CODE ErrorCode = NO_ERR; nSectorAddress = nStartingAddress; // Loop through number of sectors and erase each sector for (index = 0; index < nNumberOfSectors; index++) { // Flash device specific sector erase implementation nSectorAddress += ERASEABLE_SECTOR_SIZE; } return 1; } // End usrEraseFlashMemorySector