Flash Memory is a type of non-power-off volatile Memory. It can save data when the power is turned off. It also has the advantages of repeatable reading and writing with fast reading and writing speed, the maximum amount of data that can be stored in a unit volume, and low power consumption. Flash memory is a variant of electronically erasable read-only memory (EEPROM), which differs from flash memory in that it can be deleted and rewritten at the byte level rather than the entire chip, making flash memory faster than EEPROM. Due to its ability to save data when power is off, flash memory is often used to save Settings such as BIOS, PDAs, and digital cameras. Flash, on the other hand, does not rewrite data in bytes like RAM, so it cannot replace RAM. In recent years, the demand and capacity of Flash Memory have grown by leaps and bounds due to the development of mobile phones, PDAs, MP3, DSC, and other application systems.
The standard physical structure of Flash Memory
It’s called a cell; MOS gates and channels are normally separated by Gate oxide insulation, while Flash Memory features a floating Gate layer between the Control Gate and channels. With the help of this floating gate, Flash Memory can quickly complete three basic operation modes, such as read, write and erase. Even when no power is supplied to the memory, the integrity of the data can be preserved through the floating gate.
The electrons in a cell of a Flash Memory chip can be restored to normal by an electron region with a higher voltage. Flash Memory uses an internal closed circuit that not only allows the electron region to act on the whole chip but also allows “blocks” to be set in advance. At the same time as the block is set, the target area in the chip is erased clean, ready to be rewritten. While traditional EEPROM chips can erase only one byte at a time, Flash Memory can erase one or the whole chip at a time. Flash Memory works much faster than traditional EEPROM chips.
A technical look at FLASH MEMOR
According to the different memory transistor design architecture can be divided into Cell Type and Operation Type two, the latter according to the function can be distinguished as Code Flash(store program Code) and Data Flash(store general Data); The Code Flash driver methods include NOR AND DINOR, while the Data Flash driver methods include NAND AND AND.
The difference between NOR and NAND flash memory
NOR flash is very different from NAND flash. For example, NOR flash is more like memory, with separate address lines and data lines, but it is more expensive and has less capacity. While the NAND type is more like a hard disk, the address line and the data line a common I/O line, similar to a hard disk all the information is transmitted through a hard disk line, and the NAND type compared with NOR type flash memory, the cost is lower, and the capacity is much larger. Therefore, NOR flash memory is more suitable for frequent random read and writes occasions, usually used to store program code and run directly in the flash memory, mobile phone use NOR flash memory, so the “memory” capacity of the mobile phone is usually not large; NAND flash memory is mainly used to store data. Our commonly used flash products, such as flash drives and digital memory cards, are all NAND flash memory.