The AT45DB321D is a 2.7-volt, serial-interface sequential access Flash memory ideally suited for a wide variety of digital voice, image, program code and data-storage applications. The AT45DB321D supports RapidS serial interface for applications requiring very high speed operations. RapidS serial interface is SPI compatible for frequencies up to 66 MHz. Its 34,603,008 bits of memory are organized as 8,192 pages of 512 bytes or 528 bytes each. In addition to the main memory, the AT45DB321D also contains two SRAM buffers of 512/528 bytes each. The buffers allow the receiving of data while a page in the main Memory is being reprogrammed, as well as writing a continuous data stream. EEPROM emulation (bit or byte alterability) is easily handled with a self-contained three step read-modify-write operation. Unlike conventional Flash memories that are accessed randomly with multiple address lines and a parallel interface, the DataFlash uses a RapidS serial interface to sequentially access its data. The simple sequent ial access dramatically reduces active pin count, facilitates hardware layout, increases system reliability, minimizes switching noise, and reduces package size. The device is optimized fo r use in many commercial and industrial appli- cations where high-density, low-pin count, low-voltage and low-power are essential.
To allow for simple in-system reprogrammability, the AT45DB321D does not require high input voltages for programming. The device operates from a single power supply, 2.7V to 3.6V, for both the program and read operations. The AT45DB321D is enabled through the chip select pin (CS ) and accessed via a three-wire interface consisting of the Serial Input (SI), Serial Output (SO), and the Serial Clock (SCK).
All programming and erase cycles are self-timed.