FLASH MEMORY CARDS

PRESENTED BYRISHU (B-544)RITU (B-545)RIYA (B-546)

MEMORY CARDS Memory is a collection of storage

cells together with associated circuits needed to transfer information in and out of storage Embedded system programmers who use high-level languages require large amount of memory for storing the program.

But it is not so easy to design such type of large memory using capacitors or flip-flops.

So to tackle these problems designers are taking advantages of “flash memory” to offer feature-rich but low cost products

FLASH MEMORY CARDS A flash memory card is solid-state electronic flash memory .

data storage device capable of storing digital contents. 

The EEPROM is used due to the disadvantage of EPROM in which the memory must be removed from the board and placed in an EPROM programmer for programming and erasure procedure.

Flash memory is a nonvolatile memory using NOR AND NAND technology, which allows the user to electrically program and erase information.

HISTORY Flash memory

(both NOR and NAND types) was invented by Dr. Fujio Masuoka while working for Toshiba circa 1980.

According to Toshiba, the name "flash" was suggested by Dr. Masuoka's colleague, Mr. Shoji Ariizumi, because the erasure process of the memory contents reminded him of the flash of a camera.

DR MASUOKA Dr. Masuoka presented the invention at the IEEE 1984 International Electron Devices Meeting (IEDM) held in San Francisco, California.

Intel Corporation saw the massive potential of the invention and introduced the first commercial NOR type flash chip in 1988.

WHATS IS THE MEANING OF WORD FLASH??

A flash is a device used in photography producing a flash of artificial light (typically 1/1000 to 1/200 of a second)

at a color temperature of about 5500 K to help illuminate a scene.

A major purpose of a flash is to illuminate a dark scene.

A major purpose of a flash is to illuminate a dark scene.

Other uses are capturing quickly moving objects or changing the quality of light.

Flash refers either to the flash of light itself or to the electronic flash unit discharging the light.

WHY FLASH MEMORY IS A RIGHT SOLUTION??

LikeWe store and transfer all kinds o f files on our computers -- digital photographs, music files, wor d processing documents, PDFs and countless other forms of media

But sometimes your computer's hard drive isn't exactly where you want your information

Whether you want to make backup copies of files that live off of your systems or if you worry about your security, portable storage devices that use a type of electronic memory so we can say that flash memory may be the right solution.

EXAMPLES OF FLASH MEMORY Our computer's BIOS chip Compact Flash (most often found in

digital cameras) Smart Media (most often found in digital

cameras) Memory Stick (most often found in

digital cameras) PCMCIA Type I and Type II memory cards

(used as solid-state disks in laptops) Memory cards for video game consoles

A USB flash drive. The chip on the left is the flash memory. The microcontroller is on the right.

NOR AND NAND NOR, named after the specific data mapping

technology (Not OR), is a high-speed Flash technologY NOR Flash memory provides high-speed random-access capabilities.

being able to read and write data in specific locations in the memory without having to access the

memory in sequential mode. NOR Flash excels in applications where data is randomly retrieved or

written. NOR is most often found built in PDAs and is also used in computers to store the BIOS program that runs to

provide the start-up functionality.

NAND Flash was invented after NOR Flash, and is named after the specific mapping

technology used for data (Not AND). NAND Flash memory reads and writes in high-speed,

sequential mode, handling data in small, block sizes (“pages”). NAND Flash can retrieve or

write data as single pages, but cannot retrieve individual bytes like NOR Flash.

DIFFERENT KINDS OF APPLICATIONS IN NOR AND NAND

NOR FLASH NAND FLASH

HIGH SPEED ACCESS YES YES

PAGE MODE DATA ACCESS

NO YES

RANDOM BYTE LEVELTYPICAL USES

YESCELL PHONESBIOS STORAGE FOR PC’SNETWORKING DEVICE MEMORY

NOPDASDIGITAL CAMERASCELL PHONESMP3 PLAYERSSOLID STATE DISK DRIVESSET TOP BOXESINDUSTRIAL STORAGE

FLASH MEMORY V/S HARD DISK Flash memory is like a hard disk

drive which stores information Flash memory is noiseless. It allows faster access. It is smaller in size. It is lighter. It has no moving parts. It can plug into any computer with a

USB drive.

So why don't we just use Flash memory for everything?

Its because the cost per mega byte for a hard disk is drastically cheaper, and capacity is substantially more.

FLASH MEMORY BASICS

Flash memory is a type of EEPROM chip. It has a grid of columns and rows with a cell that has two transistors at each intersection  

The two transistors are separated from each other by a thin oxide layer. One of the transistors is known as a floating gate, and the other one is the control gate. The floating gate's only link to the row, or word line, is through the control gate. As long as this link is in place, the cell has a value of 1. To change the value to a 0 requires a curious process called Fowler-Nordheim tunneling.

23

24

FLASH MEMORY: TUNNELING AND ERASING

Tunneling is used to alter the placement of electrons in the floating gate. An electrical charge, usually 10 to 13 volts, is applied to the floating gate. The charge comes from the column, or bit line, enters the floating gate and drains to a ground.

This charge causes the floating-gate transistor to act like an electron gun. The excited electrons are pushed through and trapped on other side of the thin oxide layer, giving it a negative charge. These negatively charged electrons act as a barrier between the control gate and the floating gate.

25

26

27

The electrons in the cells of a Flash-memory chip can be returned to normal ("1") by the application of an electric field, a higher-voltage charge. Flash memory uses in-circuit wiring to apply the electric field either to the entire chip or to predetermined sections known as blocks. This erases the targeted area of the chip, which can then be rewritten. Flash memory works much faster than traditional EEPROMs because instead of erasing one byte at a time, it erases a block or the entire chip, and then rewrites it.

28

REMOVABLE FLASH MEMORY CARDS

While your computer's BIOS chip is the most common form of Flash memory, removable solid-state storage devices are becoming increasingly popular. Smart Media and Compact Flash cards are both well-known, especially as "electronic film" for digital cameras. Other removable Flash memory products include Sony's Memory Stick, PCMCIA memory cards, and memory cards for video game systems such as Nintendo's N64, Sega's Dreamcast and Sony's PlayStation. We will focus on Smart Media and Compact Flash, but the essential idea is the same for all of these products. Every one of them is simply a form of Flash memory.

29

A SONY MEMORY STICK.

30

SMART MEDIA The solid-state floppy-disk

card (SSFDC), better known as Smart Media, was originally developed by Toshiba.

Smart Media cards are available in capacities ranging from 2 MB to 128 MB. The card itself is quite small, approximately 45 mm long, 37 mm wide and less than 1 mm thick. This is amazing when you consider what is packed into such a tiny package!

.

31

Smart Media cards are elegant in their simplicity. A plane electrode is connected to the Flash-memory chip by bonding wires. The Flash-memory chip, plane electrode and bonding wires are embedded in a resin using a technique called over-molded thin package (OMTP). This allows everything to be integrated into a single package without the need for soldering

32

The OMTP module is glued to a base card to create the actual card. Power and data is carried by the electrode to the Flash-memory chip when the card is inserted into a device.

A notched corner indicates the power requirements of the Smart Media card. Looking at the card with the electrode facing up, if the notch is on the left side, the card needs 5 volts. If the notch is on the right side, it requires 3.3 volts.

33

Smart Media cards erase, write and read memory in small blocks (256- or 512-byte increments). This approach means that they are capable of fast, reliable performance while allowing you to specify which data you wish to keep. They are small, lightweight and easy to use. They are less rugged than other forms of removable solid-state storage, so you should be very careful when handling and storing them.

34

COMPACT FLASHCompact Flash cards were developed by Sandisk in 1994, and they are different from Smart Media cards in two important ways:

They are thicker. They utilize a controller chip.

35

36

Compact Flash consists of a small circuit board with Flash-memory chips and a dedicated controller chip, all encased in a rugged shell that is several times thicker than a Smart Media card.

Compact Flash cards are 43 mm wide and 36 mm long, and come in two thicknesses: Type I cards are 3.3 mm thick, and Type II cards are 5.5 mm thick.

37

COMPACT FLASH CARD

38

COMPACT FLASH CARD Compact Flash cards support dual

voltage and will operate at either 3.3 volts or 5 volts.

The increased thickness of the card allows for greater storage capacity than Smart Media cards. Compact Flash sizes range from 8 MB to 6GB.

The onboard controller can increase performance, particularly on devices that have slow processors. The case and controller chip add size, weight and complexity to the Compact Flash card when compared to the Smart Media card. 39

TYPES OF STORAGE Primary storage,

presently known as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them.

Example..RAM Secondary storage, or

storage in popular usage, differs from primary storage in that it is not directly accessible by the CPU.

Example..Hard Disk, Flash Memory

40

CONTINUE… Static Memory

A form of volatile memory similar to DRAM with the exception that it does not restore on occasion.

Dynamic Memory

A form of volatile memory which also requires the stored information to be at times re-read and re-written, or refreshed, otherwise it would vanish.

Volatile Memory

Requires constant power to maintain the stored information. Since primary storage is required to be very fast.

Non- Volatile Memory

Will retain the stored information even if it is not constantly supplied with electric power. It is suitable for long-term storage of information.

41

42

MEMORY STANDARDS

Both Smart Media and Compact Flash, as well as PCMCIA Type I and Type II memory cards, adhere to standards developed by the Personal Computer Memory Card International Association (PCMCIA).

Because of these standards, it is easy to use Compact Flash and Smart Media products in a variety of devices.

43

CONTINUE… You can also buy adapters that allow

you to access these cards through a standard floppy drive, USB port or PCMCIA card slot.

Sony's Memory Stick is available in a large array of products.

In September 2006, Samsung announced the development of PRAM -- Phase-change Random Access Memory.

This new type of memory combines the fast processing speed of RAM with the non-volatile features of flash memory, leading some to nickname it "Perfect RAM”.

PRAM is supposed to be 30 times faster than conventional flash memory and have 10 times the lifespan.

Samsung plans to make the first PRAM chips commercially available in 2010, with a capacity of 512 MB .They'll probably be used in cell phones and other mobile devices, and may even replace flash memory altogether.

APPLICATIONS OF FLASH MEMORY

The Flash Memory technology has evolved into the preferred storage media for a variety of consumer and industrial devices.

46

IN CONSUMER DEVICES, FLASH MEMORY IS WIDELY USED IN

Notebook computers Digital cameras Cell phones Electronic musical instruments Solid-state music players Television set-top boxes MP3 players Pagers Personal computers Global Positioning Systems (GPS) Personal Digital Assistants (PDAs)

47

IN INDUSTRIAL DEVICES, FLASH MEMORY IS WIDELY USED IN

Security systems Military systems Embedded computers Solid-state disk drives Networking and communication

products Wireless communication devices Retail management products (e.g.,

handheld scanners) Medical products

48

ADVANTAGE OF FLASH MEMORY

The advantages of flash memory as compared with HDDs are substantial.

Smaller in size Light weight Low power consumption Longer life Greatly improved shock resistance.

DISADVANTAGE… The main disadvantage at present is that the

cost per unit of storage capacity is still much higher than that for HDDs.

In contrast to RAM and like all types of EEPROMs, it wears out after a certain number of write and erase cycles. This is due to the degradation of the insulating oxide layer around the microscopic cells that are used to store data.

Fortunately, however, the number of cycles in most applications is sufficiently low that this situation is not frequently encountered.

Bad Blocks

SANDISK OFFERS BACKUP SOLUTION USING FLASH MEMORY There is nothing more painful than losing data on a

laptop, especially when you’re traveling. All you have to do is experience one failed hard drive to know how much your files may mean to you.

SanDisk has now offered its solution to this problem. The company has introduced the SanDisk FlashBack Adapter. The adapter makes use of an SD flash memory card to backup data which uses an ExpressCard slot in a laptop.

Once the user sets up what files they want to backup, the adapter will continuously back up data.

The adapter will also give you access to individual file restores in case you accidentally delete a file.

FAKE MEMORY CARDS Why should we care? Inferior quality card - you're not getting

what you paid for No warranty - when the card fails, you're

out of luck Fake cards sometimes have invalid

partition sizes, making it likely to fail It will drive costs of genuine cards up

EXAMPLE OF FAKE 1GB SANDISK SD CARDThis particular card was also missing a notch, making it quite easy to spot:

‘

We appreciate all of you for

sparing your valuable time

and listening to us….

THANK YOU!