Open NAND Flash Interface Working Group
Encyclopedia
The Open NAND Flash Interface Working Group (ONFI or ONFi with a lower case "i"), is a consortium
of technology companies working to develop open standards for NAND flash memory
chips and devices that communicate with them. The formation of ONFI was announced at the Intel Developer Forum
in March 2006.
The group's goals notably do not include the development of a new consumer flash memory card
format. Rather, ONFI seeks to standardize the low-level interface to raw NAND flash chips, which are the most widely used form of non-volatile memory
circuit
s today; in 2006, nearly one trillion MiB
of flash memory was incorporated into consumer electronics, and production was expected to double in 2007.
s, and accept similar sets of low-level commands. As a result, when more capable and inexpensive models of NAND flash become available, product designers can incorporate them without major design changes. However, "similar" operation is not optimal: subtle differences in timing and command set mean that products must be thoroughly debugged and tested when a new model of flash chip is used in them. When a flash controller is expected to operate with various NAND flash chips, it must store a table of them in its firmware
so that it knows how to deal with differences in their interfaces. This increases the complexity and time-to-market of flash-based devices, and means they are likely to be incompatible with future models of NAND flash, unless and until their firmware is updated.
Thus, one of the main motivations for standardization of NAND flash is to make it easier to switch between NAND chips from different producers, thereby permitting faster development of NAND-based products and lower prices via increased competition
among manufacturers. , NAND flash is increasingly a commodity
product, like SDRAM
or 3.5 in (88.9 mm) hard disk
drives. It is incorporated into many personal computer
and consumer electronics products such as USB flash drive
s, MP3 players, and solid-state drive
s. Product designers would like 2 GiB and 4 GiB NAND flash chips, for example, to be as easily interchangeable as 60 GB and 80 GB 3.5 in hard disks from different manufacturers.
s. For example, the 7400 series
of TTL digital integrated circuits were originally produced by Texas Instruments
, but had become a de facto standard family by the late 1970s. These ICs are manufactured as commodity parts by a number of different vendors. This has allowed designers to freely mix 7400 components from different vendors—and even to mix components based on different logic families, once the 74HCT sub-family become available (consisting of CMOS
components with TTL
-compatible logic levels).
Samsung
and Toshiba
, the world's largest manufacturers of NAND flash, are notably absent from the ONFI consortium.
A number of major vendors of NAND flash-based consumer electronics and computing products are also members of ONFI (see External links for the current list of members).
Version 1.0 of this specification was released on December 28, 2006, and is available at no cost from the ONFI web site (see External links). It specifies:
Version 2.0 - February 2008
ONFI 2.0 defines a high-speed NAND Flash interface that can deliver speeds greater than 133 MB/s, whereas the legacy NAND interface was limited to 50 MB/s.
Version 2.1 - January 2009
New features that deliver speeds of 166 MB/s and 200 MB/s, plus other enhancements to increase power, performance, and ECC capabilities.
Version 2.2 - October 2009
- Individual LUN reset
- Enhanced program page register clear
- New Icc specs and measurement
LUN reset and page register clear enable more efficient operation in larger systems with many NAND devices, while the standardized Icc testing and definitions will provide simplified vendor testing and improved data consistency
Block Abstracted NAND
ONFI created the Block Abstracted NAND addendum specification to simplify host controller design by relieving the host of the complexities of ECC, bad block management, and other low-level NAND management tasks. The ONFI Block Abstracted NAND revision 1.1 specification adds the high speed source synchronous interface, which provides up to a 5X improvement in bandwidth compared with the traditional asynchronous NAND interface.
The ONFI Workgroup continues to evolve the ONFI specifications to meet the needs of a rapidly growing and changing industry.
NAND Connector
The NAND Connector Specification was ratified in April of 2008. It specifies a standardized connection for NAND modules (similar to DRAM DIMMs) for use in applications like caching and SSD
s in PC platforms.
Version 3.0 - March 2011
- promotes a high-speed NAND Flash interface supporting transfer rates up to 400 MB/s
- requires fewer chip-enable pins enabling more efficient PCB
routing
- designed for the future and supports the EZ-NAND interface
News articles:
Consortium
A consortium is an association of two or more individuals, companies, organizations or governments with the objective of participating in a common activity or pooling their resources for achieving a common goal....
of technology companies working to develop open standards for NAND flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
chips and devices that communicate with them. The formation of ONFI was announced at the Intel Developer Forum
Intel Developer Forum
Intel Developer Forum , is a gathering of technologists to discuss Intel products and products based around Intel products. The first IDF was in 1997...
in March 2006.
The group's goals notably do not include the development of a new consumer flash memory card
Memory card
A memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles...
format. Rather, ONFI seeks to standardize the low-level interface to raw NAND flash chips, which are the most widely used form of non-volatile memory
Computer memory
In computing, memory refers to the physical devices used to store programs or data on a temporary or permanent basis for use in a computer or other digital electronic device. The term primary memory is used for the information in physical systems which are fast In computing, memory refers to the...
circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s today; in 2006, nearly one trillion MiB
MIB
MIB may refer to any of several concepts:* Master of International Business, a postgraduate business degree* Melayu Islam Beraja, the adopted national philosophy of Brunei* Motion induced blindness, a visual illusion in peripheral vision...
of flash memory was incorporated into consumer electronics, and production was expected to double in 2007.
Motivation
, NAND flash memory chips from most vendors use similar packaging, have similar pinoutPinout
In electronics, a pinout is a cross-reference between the contacts, or pins, of an electrical connector or electronic component, and their functions.- Purpose :...
s, and accept similar sets of low-level commands. As a result, when more capable and inexpensive models of NAND flash become available, product designers can incorporate them without major design changes. However, "similar" operation is not optimal: subtle differences in timing and command set mean that products must be thoroughly debugged and tested when a new model of flash chip is used in them. When a flash controller is expected to operate with various NAND flash chips, it must store a table of them in its firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
so that it knows how to deal with differences in their interfaces. This increases the complexity and time-to-market of flash-based devices, and means they are likely to be incompatible with future models of NAND flash, unless and until their firmware is updated.
Thus, one of the main motivations for standardization of NAND flash is to make it easier to switch between NAND chips from different producers, thereby permitting faster development of NAND-based products and lower prices via increased competition
Competition (economics)
Competition in economics is a term that encompasses the notion of individuals and firms striving for a greater share of a market to sell or buy goods and services...
among manufacturers. , NAND flash is increasingly a commodity
Commodity
In economics, a commodity is the generic term for any marketable item produced to satisfy wants or needs. Economic commodities comprise goods and services....
product, like SDRAM
SDRAM
Synchronous dynamic random access memory is dynamic random access memory that is synchronized with the system bus. Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs...
or 3.5 in (88.9 mm) hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
drives. It is incorporated into many personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
and consumer electronics products such as USB flash drive
USB flash drive
A flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...
s, MP3 players, and solid-state drive
Solid-state drive
A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...
s. Product designers would like 2 GiB and 4 GiB NAND flash chips, for example, to be as easily interchangeable as 60 GB and 80 GB 3.5 in hard disks from different manufacturers.
Historical similarities
The effort to standardize NAND flash may be compared to earlier standardization of electronic componentElectronic component
An electronic component is a basic electronic element and may be available in a discrete form having two or more electrical terminals . These are intended to be connected together, usually by soldering to a printed circuit board, in order to create an electronic circuit with a particular function...
s. For example, the 7400 series
7400 series
The 7400 series of transistor-transistor logic integrated circuits are historically important as the first widespread family of TTL integrated circuit logic. It was used to build the mini and mainframe computers of the 1960s and 1970s...
of TTL digital integrated circuits were originally produced by Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
, but had become a de facto standard family by the late 1970s. These ICs are manufactured as commodity parts by a number of different vendors. This has allowed designers to freely mix 7400 components from different vendors—and even to mix components based on different logic families, once the 74HCT sub-family become available (consisting of CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
components with TTL
Transistor-transistor logic
Transistor–transistor logic is a class of digital circuits built from bipolar junction transistors and resistors. It is called transistor–transistor logic because both the logic gating function and the amplifying function are performed by transistors .TTL is notable for being a widespread...
-compatible logic levels).
Members
The ONFI consortium is led by several prominent manufacturers of NAND flash memory:- HynixHynixHynix Semiconductor Inc. chips and flash memory chips. Founded in 1983, Hynix is the world's second-largest memory chipmaker, the largest being Samsung Electronics. Formerly known as Hyundai Electronics, the company has manufacturing sites in Korea, the U.S., China and Taiwan...
- Intel
- Micron TechnologyMicron TechnologyMicron Technology, Inc. is an American multinational corporation based in Boise, Idaho, USA, best known for producing many forms of semiconductor devices. This includes DRAM, SDRAM, flash memory, SSD and CMOS image sensing chips. Consumers may be more familiar with its consumer brand Crucial...
- PhisonPhisonPhison Electronics Corporation is a public Taiwanese electronics company that primarily manufactures controllers for NAND flash memory chips. These are integrated into flash-based products such as USB flash drives, memory cards, and solid-state drives...
- SanDiskSanDiskSanDisk Corporation is an American multinational corporation that designs, develops and manufactures data storage solutions in a range of form factors using the flash memory, controller and firmware technologies. It was founded in 1988 by Dr. Eli Harari and Sanjay Mehrotra, non-volatile memory...
- SonySony, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
- NumonyxNumonyxNumonyx is a semiconductor company making flash memories, which was founded on March 31, 2008 by Intel Corporation, STMicroelectronics and Francisco Partners. It was acquired by Micron Technology on February 9, 2010....
Samsung
Samsung
The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...
and Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
, the world's largest manufacturers of NAND flash, are notably absent from the ONFI consortium.
A number of major vendors of NAND flash-based consumer electronics and computing products are also members of ONFI (see External links for the current list of members).
ONFI standard
ONFI has produced a specification for a standard interface to NAND flash chips.Version 1.0 of this specification was released on December 28, 2006, and is available at no cost from the ONFI web site (see External links). It specifies:
- a standard physical interface (pinoutPinoutIn electronics, a pinout is a cross-reference between the contacts, or pins, of an electrical connector or electronic component, and their functions.- Purpose :...
) for NAND flash in TSOPThin small-outline packageThin small-outline packages, or TSOPs are a type of surface mount IC package. They are notably very low-profile and have tight lead spacing ....
-48, WSOP-48, LGALand grid arrayThe land grid array is a type of surface-mount packaging for integrated circuits that is notable for having the pins on the socket rather than the integrated circuit...
-52, and BGABall grid arrayA ball grid array is a type of surface-mount packaging used for integrated circuits.- Description :The BGA is descended from the pin grid array , which is a package with one face covered with pins in a grid pattern. These pins conduct electrical signals from the integrated circuit to the printed...
-63 packages - a standard mechanism for NAND chips to identify themselves and describe their capabilities (comparable to the Serial Presence DetectSerial Presence DetectSerial presence detect refers to a standardized way to automatically access information about a computer memory module. Earlier 72-pin SIMMs included 5 pins which provided 5 bits of parallel presence detect data, but the 168-pin DIMM standard changed to a serial presence detect to encode much...
ion feature of SDRAMSDRAMSynchronous dynamic random access memory is dynamic random access memory that is synchronized with the system bus. Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs...
modules) - a standard command set for reading, writing, and erasing NAND flash
- standard timing requirements for NAND flash
- improved performance via a standard implementation of read cacheCacheIn computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...
and increased concurrencyConcurrency (computer science)In computer science, concurrency is a property of systems in which several computations are executing simultaneously, and potentially interacting with each other...
for NAND flash operations - improved data integrity by allowing optional ECC memory features
Version 2.0 - February 2008
ONFI 2.0 defines a high-speed NAND Flash interface that can deliver speeds greater than 133 MB/s, whereas the legacy NAND interface was limited to 50 MB/s.
Version 2.1 - January 2009
New features that deliver speeds of 166 MB/s and 200 MB/s, plus other enhancements to increase power, performance, and ECC capabilities.
Version 2.2 - October 2009
- Individual LUN reset
- Enhanced program page register clear
- New Icc specs and measurement
LUN reset and page register clear enable more efficient operation in larger systems with many NAND devices, while the standardized Icc testing and definitions will provide simplified vendor testing and improved data consistency
Block Abstracted NAND
ONFI created the Block Abstracted NAND addendum specification to simplify host controller design by relieving the host of the complexities of ECC, bad block management, and other low-level NAND management tasks. The ONFI Block Abstracted NAND revision 1.1 specification adds the high speed source synchronous interface, which provides up to a 5X improvement in bandwidth compared with the traditional asynchronous NAND interface.
The ONFI Workgroup continues to evolve the ONFI specifications to meet the needs of a rapidly growing and changing industry.
NAND Connector
The NAND Connector Specification was ratified in April of 2008. It specifies a standardized connection for NAND modules (similar to DRAM DIMMs) for use in applications like caching and SSD
Solid-state drive
A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...
s in PC platforms.
Version 3.0 - March 2011
- promotes a high-speed NAND Flash interface supporting transfer rates up to 400 MB/s
- requires fewer chip-enable pins enabling more efficient PCB
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
routing
- designed for the future and supports the EZ-NAND interface
External links
- Official website
- List of ONFI member companies
- Version 3.0 of the official ONFI specification
- Version 1.1 of the official ONFI Block Abstracted NAND specification
- ONFI Specification Downloads and Revision History
News articles:
- Article from Dr. Dobb's JournalDr. Dobb's JournalDr. Dobb's Journal was a monthly journal published in the United States by CMP Technology. It covered topics aimed at computer programmers. DDJ was the first regular periodical focused on microcomputer software, rather than hardware. It later became a monthly section within the periodical...
: "Simplify Your Flash-Memory Interface" (September 25, 2006) - Article from The RegisterThe RegisterThe Register is a British technology news and opinion website. It was founded by John Lettice, Mike Magee and Ross Alderson in 1994 as a newsletter called "Chip Connection", initially as an email service...
's hardware division: "Vendors pledge to make Flash as easy to upgrade as RAM" (January 22, 2007) - Article from The RegisterThe RegisterThe Register is a British technology news and opinion website. It was founded by John Lettice, Mike Magee and Ross Alderson in 1994 as a newsletter called "Chip Connection", initially as an email service...
's hardware division: "Intel primes Flash standardisation push" - Article on ONFi Verification IP "First Verification IP on ONFi 2.1"