The AT45DB021 is a 2.7-volt only, serial interface Flash memory suitable for in-system reprogramming. Its 2,162,688 bits of memory are organized as 1024 pages of 264-bytes each. In addition to the main memory, the AT45DB021 also contains two SRAM data buffers of 264-bytes each. The buffers allow receiving of data while a page in the main memory is being reprogrammed. Unlike conventional Flash memories that are accessed randomly with multiple address lines and a parallel interface, the DataFlash uses a serial interface to sequentially access its data. The simple serial interface facilitates hardware layout, increases system reliability, minimizes switching