Tag Archives: FLASH

Understanding Flash Memory And How It Works

Flash memory is one of the most widely used types of non-volatile memory. NAND Flash is designed for modern file storage which replaced old disk drives. This article provides a brief understanding of how NAND Flash technology works.

The basic storage component used in Flash memory is a modified transistor. In a standard transistor, the flow of current through a channel between two contacts is turned on by a voltage applied to the gate. The channels are separated by an insulating layer of Oxide. In a Flash storage cell, there is an extra electrically isolated gate called “floating gate”. It is added to the control gate and the channel of the modified transistor.

Different Flash Storages
Different Flash Memory Devices

High voltage is applied to the control gate of The Flash cell to program it. This pushes electrons to pass through the oxide layer to the floating gate (a process known as tunneling). The presence of these trapped electrons on the floating gate changes the required voltage to turn on the transistor. Thus, a transistor with no charge on the floating gate can easily turn on at a certain voltage, representing a 1, while a programmed cell will not turn on, representing a 0.

This kind of memory is non-volatile because the floating gate is surrounded by dielectric layers, it traps the electric charge even when the power is removed. Erasing a cell reverses this process by introducing a large negative voltage to the control gate to force the electrons to tunnel out of the floating gate.

NANAD Flash storage internal
NAND Flash Memory storage internal

A number of cells, typically 32 to 128, are connected in a string. Strings are organized in blocks. To program cells in a block, the data is put on the bit lines and a high voltage is applied. Because programming can only change a cell from a 1 to a 0, any cells where the new data is a 1, will be left in their current state. Therefore, all the cells must be erased before writing. This process ensures that any cells that will not be programmed already contain a 1.

As explained above, each cell can store a single binary value, 0 or 1. It is also possible to inject varying amounts of charge onto the floating gate so that the cell can express multiple values. A multi-level cell (MLC) can store four different levels to represent two bits. However, the performance is reduced because of the complexity of accurate voltage controls. For the same reason, MLC Flash memory is more inclined to errors.

Although flash memory has a limited number of write-erase cycles, the high voltages cause a small amount of damage to the cells which makes them harder to read-write over time. The main drawback of using a flash memory is that it has a lifetime of about 100,000 cycles or fewer for MLC Flash.

Writing to flash and EEPROM on the tinyAVR 1-series

Update your tinyAVR code to access memories when using 1-series tinyAVRs. Link here (PDF)

On tinyAVR® 1-series devices, access to Flash memory and EEPROM has been changed from that on previous tinyAVR devices. This means that existing code for writing to Flash and EEPROM on older devices must be modified in order to function properly on tinyAVR 1-series devices. This application note describes what has changed and how to adapt code to these changes.

Writing to flash and EEPROM on the tinyAVR 1-series – [Link]

512Gbyte embedded universal flash memory in production

Samsung Electronics has begun mass production of what the company claims to be the industry’s first 512-gigabyte (GB) embedded Universal Flash Storage (eUFS) solution for use in next-generation mobile devices. by Julien Happich  @ eenewseurope.com:

The 512GB eUFS packs eight of Samsung’s latest 64-layer 512-gigabit (Gb) V-NAND chips together with a controller chip, doubling the density of Samsung’s previous 48-layer V-NAND-based 256GB eUFS in the same amount of space as the 256GB package. The new high-capacity eUFS enables a flagship smartphone to store approximately 130 4K Ultra HD (3840×2160) video clips of a 10-minute duration. To maximize the performance and energy efficiency of the new 512GB eUFS, Samsung has introduced a new set of proprietary technologies. The 512GB eUFS’ controller chip speeds up the mapping process for converting logical block addresses to those of physical blocks. With its sequential read and writes reaching up to 860 megabytes per second (MB/s) and 255MB/s respectively, the 512GB embedded memory enables transferring a 5GB-equivalent full HD video clip to an SSD in about six seconds, over eight times faster than a typical microSD card.

512Gbyte embedded universal flash memory in production – [Link]

SST26WF064C – Low-voltage 64-Megabit SuperFlash® Memory Device From Microchip

Microchip introduced a new 64Mbit Serial Quad I/O memory device—SST26WF064C with proprietary SuperFlash® technology. The SST26WF064C writes with a single power supply of 1.65-1.95V and significantly lower power consumption. This makes it ideal for wireless, mobile, and battery-powered applications.

Microchip SST26WF064C Flash Memory Chip
Microchip SST26WF064C Flash Memory Chip

This 64Mbit memory device also features DTR or Dual Transfer Rate technology. DTR lets the user access data of the chip on both rising and falling edges of the clock, reducing overall data access time and power consumption significantly. The SST26WF064C utilizes a 4-bit multiplexed I/O serial interface to boost performance while maintaining the tiny form factor of standard serial flash devices.

Microchip’s high-performance CMOS SuperFlash technology provides the fastest chip erase time, consequently, reduces overall power consumption. It also improves performance and reliability of the memory chip. The SST26WF064C’s typical chip-erase time is 35-50 milliseconds, where other chips take nearly 30 seconds to be completely erased.

This chip combines a hardware controlled RESET function which is not present in common flash chips available in the market due to their limited pin count. In SST26WF064C, the user can program the HOLD pin to use for the RESET function. This feature lets the host microcontroller to reset the chip by sending a pulse to it.

SST26WF064C supports full command-set compatibility with traditional Serial Peripheral Interface (SPI) protocol. Operating at frequencies reaching 104 MHz, the SST26WF064C enables minimum latency execute-in-place (XIP) capability without the need for code shadowing on a SRAM. To learn about code shadowing, read this article.

The key features of the SST26WF064C are:

  • Single Voltage Read and Write Operations – 1.65-1.95V
  • Serial Interface Architecture
  • High-Speed Clock Frequency (104 MHz max.)
  • Burst Modes
  • Superior Reliability
  • Low Power Consumption
  • Fast Erase Time
  • Flexible Erase Capability
  • Suspend Program or Erase operation to access another block/sector
  • Software and Hardware Reset mode
  • Software Protection
  • Security ID
  • One-Time Programmable (OTP) 2KByte Secure ID
  • 64 bit unique, factory pre-programmed identifier
  • User-programmable area

To learn more about this memory chip or to purchase some, visit http://www.microchip.com/wwwproducts/en/SST26WF064C.

96-Layer Memory Chips By Toshiba

The need for larger memory storage for smartphones will never stop, especially with the continuous development of larger and stronger applications. This need is always pushing semiconductor manufacturers to keep trying to fit as much bits as possible in  smaller volumes and with lower costs.

To achieve this, memory chips are now growing in three dimensions instead of two. Recently, Toshiba has developed a new 96-layer BiCS 3D flash memory device with a storage capacity of 32 GB. The new device meets market demands and performance specifications for applications that include enterprise and consumer SSD, smartphones, tablets and memory cards.

This memory chip was built with three bits per cell, known as triple-level cell (TLC) technology. Stacking layers and manufacturing process increase the capacity of each chip with 40% per unit size. They also reduce the cost per bit, and increase the manufacturability of memory capacity per silicon wafer.

In order to add more layers to the chip, Toshiba is working on increasing the number of bits in every cell. In the near future, it will apply its new 96-layer process technology to larger capacity products, such as 64 GB. It will also develop chips with QLC (quadruple-level cell) technology.

By stacking 64 layers of QLCs, the engineers at Toshiba have created a 96-gigabyte device. Integrating 16 of them in one package will achieve a capacity of 1.5 TB, that corresponds to 12 trillion bits.

If you are interested, you can check these out at the 2017 Flash Memory Summit in Santa Clara, California from August 7-10.

Source: elektor

SK Hynix Introduces Industry’s Highest 72-Layer 3D NAND Flash

SK Hynix Incorporated introduced the world’s first 72-Layer 256Gb (Gigabit) 3D (Three-Dimensional) NAND Flash based on its TLC (Triple-Level Cell) arrays and own technologies. This company also launched 6-Layer 128Gb 3D NAND chips in April 2016 and has been mass producing 48-Layer 256Gb 3D NAND chips since November 2016. Within 5 months the researchers in SK Hynix developed the new technology of producing 72-layer 3D NAND flash.

3D NAND flash 72 layers
72 layers 3D NAND flash

The technological achievement of this 72-Layer 3D NAND is compared to the difficulty of building approximately 4 billion 72-storied skyscrapers on a single dime. Well, now the question maybe, “Is the difficulty and complexity of this new technology giving any remarkable outcome?”. The answer is a big YES. The 72-layer NAND is said to stack 1.5 times more cells than the 48-layer, achieving 30% more efficiency in productivity and 20% higher read/write performance than a 48-layer 3D NAND chip, the predecessor of this 72-layer .D 256Gb NAND flash.

With this new chips having 30% more efficiency in productivity and 20% higher performance, SK Hynix has been currently developing NAND Flash solutions such as SSD (Solid State Drive) and storage for mobile devices such as smartphones. Having high reliability and low power consumption this 3D NAND flash should be an ideal solution for storage problems of mobile devices.

SK Hynix plans to expand the usage of the product to SSDs and mobile gadgets to further improve its business structure weighted towards DRAM. The vice president Jong Ho Kim said in the press release,

With the introduction of this industry’s highest productivity 3D NAND, SK Hynix will mass produce the 256Gb 3D NAND in the second half of this year to provide this to worldwide business clients for optimum use in storage solutions

According to a market research, 3D NAND flash demand is rapidly increasing across AI(Artificial Intelligence), big data, and cloud storage. The research by Gartner says that NAND Flash market revenue is expected to total USD 46.5 billion in this year and it will grow up to an amount of USD 56.5 billion in 2021.

64-layer flash IC enables 1-Tbyte chips

Susan Nordyk @ edn.com writes:

Toshiba has added a 512-Gbit (64-Gbyte), 64-layer flash memory device that employs 3-bit-per-cell TLC (triple-level cell) technology to its BiCS Flash product line. This technology will allow the development of 1-terabyte memory chips for use in enterprise and consumer solid-state drives.

64-layer flash IC enables 1-Tbyte chips – [Link]

Slave Flash Trigger

A Programmable Optical Slave Flash Trigger for Digital Cameras with PIC 12F675

Slave Flash Trigger – [Link]

How to Upgrade Your ESP8266 SPI Flash to 4MB

ESP8266, the well known WiFi module contains an ESP8266EX SoC IC and an external SPI flash. This external SPI flash is used together with ESP8266EX to store user programs.

The supported size of flash by ESP8266EX is up to 16MB but some of ESP8266 modules contain flash chips with low storage capacity like 512KB. In some cases you need more space. For example, if the upgrade Over The Air “OTA is enabled: the minimum flash memory that can be supported is 1 Mbyte” according to ESP8266EX datasheet.

The SPI flash used in ESP8266 modules is W25qxx from Winbond, and in order to upgrade your flash memory you need to remove the old chip soldered to your module PCB and then solder the new one W25Q32 (32M-bit / 4M-byte), which can be ordered from Aliexpress.


[Code and Solder] channel over Youtube shared with us how to do the upgrade process.

Via: embedsysweekly

Samsung and Toshiba Will Start 64-layer 3D NAND Production Soon

Toshiba will start mass production of 64-layer 3D NAND, BiCS3, with 3-bit-per-cell technology and a 64GB capacity in the first half of 2017. The applications of this new massive storage chip include enterprise and consumer SSD, smartphones, tablets and memory cards. This achievement succeeds the 48-layer BiCS FLASH one.

Western Digital, the well known industry-leading provider of storage technologies, recently announced world’s first 64 Layer 3D NAND. “BiCS3 has been developed jointly with Western Digital’s technology and manufacturing partner Toshiba. It will be initially deployed in 256 gigabit(32GB) capacity” according to Western Digital’s press release.

In the same context, Samsung seems going to start production of 64-layer 3D NAND at the end of this year 2016.


Via: electronicsweekly 1&2