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 An open standard is a standard that is openly accessible and usable by anyone. It is also a prerequisite to use open license, non-discrimination and extensibility. Typically, anybody can participate in the development. There is no single definitio ...

for NAND

flash memory Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both u ...

and devices that communicate with them. The formation of ONFI was announced at the

Intel Developer Forum The Intel Developer Forum (IDF) was a biannual gathering of technologists to discuss Intel products and products based on Intel products. The first IDF was held in 1997. To emphasize the importance of China, the Spring 2007 IDF was held in Beij ...

in March 2006.

History

The group's goals did ''not'' include the development of a new consumer flash

memory card A memory card is an electronic data storage device used for storing digital information, typically using flash memory. These are commonly used in digital portable electronic devices. They allow adding memory to such devices using a card in a soc ...

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 Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data. Non-volatile memory typi ...

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...

integrated circuits (chips); in 2006, nearly one trillion

MiB The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...

of flash memory was incorporated into consumer electronics, and production was expected to double by 2007. , NAND flash memory chips from most vendors used similar packaging, had similar

pinout In electronics, a pinout (sometimes written "pin-out") is a cross-reference between the contacts, or ''pins'', of an electrical connector or electronic component, and their functions. "Pinout" now supersedes the term "basing diagram" that was the s ...

s, and accepted 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: See section "The Curse of Similarity" in this white paper by Arun Kamat of

Hynix SK hynix Inc. is a South Korean supplier of dynamic random-access memory (DRAM) chips and flash memory chips. Hynix is the world's second-largest memory chipmaker (after Samsung Electronics) and the world's third-largest semiconductor company. ...

. subtle differences in timing and command set mean that products must be thoroughly

debug In computer programming and software development, debugging is the process of finding and resolving ''bugs'' (defects or problems that prevent correct operation) within computer programs, software, or systems. Debugging tactics can involve int ...

ged and tested when a new model of flash chip is used in them. When a

flash controller A flash memory controller (or flash controller) manages data stored on flash memory (usually NAND flash) and communicates with a computer or electronic device. Flash memory controllers can be designed for operating in low duty-cycle environments ...

is expected to operate with various NAND flash chips, it must store a table of them in its

firmware In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide ...

so that it knows how to deal with differences in their interfaces. This increases the complexity and

time-to-market In commerce, time to market (TTM) is the length of time it takes from a product being conceived until its being available for sale. The reason that time to market is so important is since being late erodes the addressable market into which prod ...

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 was 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 is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, ind ...

among manufacturers. By 2006, NAND flash became increasingly a

commodity In economics, a commodity is an economic good, usually a resource, that has full or substantial fungibility: that is, the market treats instances of the good as equivalent or nearly so with no regard to who produced them. The price of a co ...

product,See thi
presentation
by Amber Huffman and Michael Abraham of

Micron The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Un ...

. like

SDRAM Synchronous dynamic random-access memory (synchronous dynamic RAM or SDRAM) is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal. DRAM integrated circuits (ICs) produced from the ...

hard disk A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with mag ...

drives. It is incorporated into many

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tech ...

and consumer electronics products such as

USB flash drive A USB flash drive (also called a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, rewritable and much smaller than an optical disc. Most weigh less than . Since fir ...

MP3 player A portable media player (PMP) (also including the related digital audio player (DAP)) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. The data is typically stored o ...

s, and

solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It i ...

s. Product designers wanted newer NAND flash chips, for example, to be as easily interchangeable as hard disks from different manufacturers.

Historical similarities

The effort to standardize NAND flash may be compared to earlier standardization of

electronic component An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are n ...

s. For example, the

7400 series The 7400 series of integrated circuits (ICs) are a popular logic family of transistor–transistor logic (TTL) logic chips. In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A low- ...

of TTL digital

integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Transistor count, Large ...

were originally produced by

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...

, 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 In computer engineering, a logic family is one of two related concepts: * A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compat ...

, once the 74HCT sub-family become available (consisting of CMOS components with TTL-compatible logic levels).

Members

The ONFI consortium included manufacturers of NAND flash memory such as

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the devel ...

Micron Technology Micron Technology, Inc. is an American producer of computer memory and computer data storage including dynamic random-access memory, flash memory, and USB flash drives. It is headquartered in Boise, Idaho. Its consumer products, including ...

Phison Phison Electronics Corporation () is a Taiwanese public electronics company that primarily designs, manufactures and sells controllers for NAND flash memory chips. These are integrated into flash-based products such as USB flash drives, memor ...

Western Digital Western Digital Corporation (WDC, commonly known as Western Digital or WD) is an American computer drive manufacturer and data storage company, headquartered in San Jose, California. It designs, manufactures and sells data technology products ...

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

and

Spansion Spansion Inc. was an American-based company that designed, developed, and manufactured flash memory, microcontrollers, mixed-signal and analog products, and system-on-chip (SoC) solutions.Reuters.Spansion Inc." July 26, 2010.By Mark LaPedus, EE ...

Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...

, the world's largest manufacturer of NAND flash, was absent in 2006. Vendors of NAND flash-based consumer electronics and computing products are also members.

Specifications

ONFI produced

specification A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard. There are different types of technical or engineering specificat ...

s for standard interface to NAND flash chips. Version 1.0 of this specification was released on December 28, 2006, and made available at no cost from the ONFI web site. Samsung was still not a participant. It specified: * a standard physical interface (

) for NAND flash in TSOP-48, WSOP-48,

LGA LaGuardia Airport is a civil airport in East Elmhurst, Queens, New York City. Covering , the facility was established in 1929 and began operating as a public airport in 1939. It is named after former New York City mayor Fiorello La Guardia. ...

-52, and BGA-63 packages * a standard mechanism for NAND chips to identify themselves and describe their capabilities (comparable to the

Serial Presence Detect In computing, serial presence detect (SPD) is a standardized way to automatically access information about a memory module. Earlier 72-pin SIMMs included five pins that provided five bits of ''parallel presence detect'' (PPD) data, but the 168-pi ...

ion feature of

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

cache Cache, caching, or caché may refer to: Places United States * Cache, Idaho, an unincorporated community * Cache, Illinois, an unincorporated community * Cache, Oklahoma, a city in Comanche County * Cache, Utah, Cache County, Utah * Cache Coun ...

and increased

concurrency Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a ...

for NAND flash operations * improved data integrity by allowing optional

error-correcting code In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea i ...

(ECC) features A verification product was announced in June 2009. Version 2.3 was published in August 2010. It included a protocol called EZ-NAND that hid ECC details. Version 3.0 was published in March 2011. It required fewer chip-enable pins enabling more efficient

printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...

routing. A standard developed jointly with the

JEDEC The JEDEC Solid State Technology Association is an independent semiconductor engineering trade organization and standardization body headquartered in Arlington County, Virginia, United States. JEDEC has over 300 members, including some of the w ...

was published in October 2012. Version 3.1, published in october of 2012, includes errata to the original ONFI 3.0 specification, adds LUN SET/GET Features commands, and implements additional data setup and hold values for NV-DDR2 interface. Version 3.2, published on July 23, 2013, raised the data rate to 533 MB/s. Version 4.0, published on April 17, 2014, introduced the NV-DDR3 interface increases the maximum switching speed from 533 MB/s to 800 MB/s, providing a performance boost of up to 50% for high performance applications enabled by solid-state NAND storage components. Version 4.1, published on December 12, 2017, extends NV-DDR3 I/O speeds to 1066 MT/s and 1200MT/s. For better signaling performance, ONFI 4.1 adds Duty Cycle Correction (DCC), Read and Write Training for speeds greater than 800MT/s, support for lower pin cap devices with 37.5 Ohms default output resistance, and devices which require data burst exit and restart for long data input and output pauses. For lower power, 2.5V Vcc support is added. ONFI 4.1 also includes errata to the ONFI 4.0 specification. Version 4.2, published on February 12, 2020, extends NV-DDR3 I/O speeds to 1333MT/s, 1466MT/s and 1600MT/s. The BGA-252b four channel package is introduced which has a smaller footprint than the existing BGA-272b four channel package. To enable higher IOPS multi-plane operations, addressing restrictions related to multi-plane operations are relaxed. Version 5.0, Published in May of 2021, ONFI5.0 extends NV-DDR3 I/O speeds up to 2400MT/s. A new NV-LPDDR4 lower power interface is introduced with speeds up to 2400MT/s. With the NV-LPDDR4 interface, an optional Data Bus Inversion (DBI) feature is defined. New smaller footprint BGA-178b, BGA-154b and BGA-146b packages are added. ONFI5.0 also includes other errata related to the ONFI4.2 specification.

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.

NAND Connector

The NAND Connector Specification was ratified in April 2008. It specifies a standardized connection for NAND modules (similar to DRAM DIMMs) for use in applications like caching and

s (SSDs) in PC platforms.

References

External links

* {{authority control Computer memory Non-volatile memory Standards organizations in the United States Technology trade associations Organizations based in Oregon