AMD_EraseChip
Default mainpageat91libmemoriesnorflashAMD_EraseChip
Description Source Call Graph
Start Line: 319
unsigned char AMD_EraseChip(struct NorFlashInfo *pNorFlashInfo)
{
    unsigned int pollingData;
    unsigned char busWidth;
    unsigned int address;
    unsigned char done = 0;
        
    busWidth = NorFlash_GetDataBusWidth(pNorFlashInfo);
    
    //Programming is a six-bus-cycle operation. 
    // The erase command sequence is initiated by writing two unlock write cycles.
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_1),
                 AMD_CMD_UNLOCK_1);
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_2), 
                 AMD_CMD_UNLOCK_2);
    // Followed by the program set-up command.               
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_1),
                 AMD_CMD_ERASE_SETUP);
                 
    // Two additional unlock cycles are written.                 
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_1), 
                 AMD_CMD_UNLOCK_1);
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_2), 
                 AMD_CMD_UNLOCK_2);
                 
    // Then followed by the chip erase command.
    WriteCommand(busWidth , 
                 NorFlash_GetByteAddressInChip(pNorFlashInfo, AMD_OFFSET_UNLOCK_1), 
                 AMD_CMD_ERASE_CHIP);
                 
    address = NorFlash_GetByteAddressInChip(pNorFlashInfo, 0);              
    // Data polling 
    do {
        ReadRawData(busWidth , address, (unsigned char*)&pollingData);
        // Check if the chip erase algorithm is completed.
        if ((pollingData & AMD_POLLING_DQ7) == AMD_POLLING_DQ7 ) {
            // Erase operation successful. Device in read mode.
            done = 1;
        }
        else {
            
            // When the time-out period is complete, DQ3 switches from a ¡°0¡± to a ¡°1.¡±
            if (pollingData & AMD_POLLING_DQ3 ) {
                return NorCommon_ERROR_CANNOTERASE;
            }
            // check if chip earse algrithm exceeded timing limits
            if (pollingData & AMD_POLLING_DQ5 ) {
                
                // I/O should be rechecked.
                ReadRawData(busWidth , address, (unsigned char*)&pollingData);
                if ((pollingData & AMD_POLLING_DQ7) == AMD_POLLING_DQ7 ){
                    // Erase operation successful. Device in read mode.
                    done = 1;
                }
                else {
                    // Erase operation not successful, write reset command.
                    amd_Reset(pNorFlashInfo, 0);
                    return NorCommon_ERROR_CANNOTERASE;
                }
            }
        }
    } while (!done);
    return 0;
}