pfdl Data flash read function problem

Hi,

   I am using Rl78 F13 (R5F10BMG).

while writing into data flash through data flash library function

 FDL_Request.index_u16=address;                                   //Start Address of Data Flash (For R5F100LE, Data Flash range from (0xF1000 - 0xF1FFF)
FDL_Request.data_pu08=data_buffer;                               //Assign the address of Write_DataBuffer as data to be stored in Data Flash
FDL_Request.bytecount_u16=bytecnt;                               //Counter for number of bytes to be write
FDL_Request.command_enu =PFDL_CMD_WRITE_BYTES;   //Assign the command to be execute by PFDL_Execute
PFDL_Execute(&FDL_Request);  

Writing data is done properly and it shown in memory (in IDE CS+ CACX)

but while reading...

FDL_Request.index_u16=address; 
FDL_Request.data_pu08=dummy_buffer; 
FDL_Request.bytecount_u16=bytecnt; 
FDL_Request.command_enu =PFDL_CMD_READ_BYTES; 
PFDL_Execute(&FDL_Request); 

I used buffer (dummy_buffer) , it read correct data but after appox 30ms this buffer is RESET. Data is still present in data flash memory but only issue in dummy buffer reading , I make it as volatile const still it will reset.

please tell me what wrong in this process.