Download MSC-Newsletter: Newsletter 5/2005: DataFlash™..."parallel goes serial" [PDF 142KB] DataFlash™..."parallel goes serial"

DataFlash™ a trademark from Atmel®, is an expression for a non-volatile memory technology using SPI as a standard communication interface. Since this kind of communication is not really new some additional features have been implemented to improve performance and access.

- Densities up to 128MBit - SPI interface speed up to 50Mbit/s - RapidS™ interface speed up to 66Mbit/s - two SRAM page buffer - Very small packages SOIC8, CASON and MLF

DataFlash™ Architecture
		Beside traditional serial E²PROM memories, DataFlash™ offer additional functionality to conform to user's requirements. The main special features are the two internal SRAM page buffers which are used for fast data buffering between the user interfaces (SPI) and the Flash-memory. Pages may be read from the Flash-memory into the SRAM page buffer, modified and write back while the next page is read into the other page buffer (Read-While-Write). Since speed critical erase/write operation are done while read operations are executed, the overall system performance will increase dramatically.

Why using DataFlash™

The key is "system cost". The total cost of a system will be basically driven by device and manufacturing cost. Parallel memories require many pins and therefore results in a big package and higher cost. Serial memories like DataFlash™ from Atmel® only need some few pins for communication. A traditional 32Mbit Flash-memory with a parallel interface needs at least 48-pins while a serial same density flash only needs 8-pins.

Cost reduction in manufacturing is the next advantage when using serial flash-memories. While parallel memories do need many traces on the PCB to be routed with the microcontroller a serial memory does not. This might result in a reduction of PCB-layer and so also in cost.

DataFlash™ Applications
	A typical DataFlash™ application exists in conjunction with a microcontroller. Like in a conventional memory system, the DataFlash™ also stores program and data information. The optimal use of a DataFlash™ will only work together with a selected microcontroller. On the left side of the block diagram a traditional microcontroller application is shown, consisting of a Flash-memory for code and non-volatile data and a SRAM memory for temporary data. Since both components are very expensive, a microcontroller has to be selected which is capable using other, more cost effective memory solutions. Atmels® AT91RM9200 has a SDRAM interface which allows the use of very low-cost SDRAM memories. The on-chip boot loader shadows the program code of the DataFlash™ into SDRAM at start-up. One positive side effect of this solution also is that the SDRAM also may be executed faster than a flash memory.

DataFlash™ an Overview

This table shows all DataFlash™ members which may be used for current and new designs and will be also provided in "green only". Firmware Flash are primary designed for PC systems and will be used for BIOS applications. These Firmware memories are based upon Atmel® series AT25-pinout.

DataFlash™
Device	Flash@MBit	SPI	RapidS™	Package	Status
AT45D/DB011	1	50MHz	66MHz	8SOIC	D-Revision January 2006
AT45D/DB021	2	50MHz	66MHz	8SOIC	D-Revision February 2006
AT45D/DB041	4	50MHz	66MHz	8SOIC	D-Revision October 2005
AT45D/DB081	8	50MHz	66MHz	8SOIC	D-Revision September 2005
AT45D/DB161	16	50MHz	66MHz	8SOIC	D-Revision August 2005
AT45D/DB321	32	50MHz	66MHz	8SOIC	D-Revision November 2005
AT45D/DB641	64	50MHz	66MHz	8CASON	D-Revision July 2005
AT45D/DB128	128	50MHz	66MHz	8CASON	D-Revision September 2005
Firmware Flash
Device	Flash@MBit	SPI	RapidS™	Package	Status
AT26DF041	4	33MHz	-	8SOIC/MLF	April 2005
AT26DF081	8	50MHz	-	8SOIC/MLF	June 2005
AT26DF161	16	50MHz	-	8SOIC/MLF	July 2005

This status only covers Revision D. Devices in Revision B&C are already available but not as fast. For more Information don't hesitate to contact us: Atmel@msc-ge.com

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