Relationship and difference between nor and NAND memory

1. Understanding of Types

Divided into nor (or non) nand (and non)

2. Interface understanding

Nor (or not) ---- separate addresses and Data Bus;

Nand (non-) ---- address and Data Bus Sharing.

Iii. read/write units:

Nor (or not )----Bytes;

 Nand (and non-) ---- page.

Iv. Composition:

Nor (or not) ---- sector, byte;

Nand (and non-) ---- blocks and pages;

5. Erased unit:

Nor (or not) ---- sector;

Nand (and non-) ---- Block;

Vi. Differences in principles:

A. Differences between flash and EEPROM

Their storage units are basically the same,Flash storage unitSource poleThey are all connected together. Therefore, the erased object is erased together.,

WhileThe EEPROM can be erased independently by byte.,

Both EEPROM, EPROM, and Flash are based onFloating Gate Transister).

The floating gate of the EPROM is in the insulating silica layer, and only the electronic charge can be used.Ultraviolet energy,

The eeprom unit is composed of flotox (Floating-gate tuneling oxide Transister) and an additional Transister. Because of the characteristics of flotox and the two-tube structure, it can be read/written by the Unit.

Technically,Flash is achieved by combining EPROM and EEPROM technology., A lot of Flash useProgramming by avalanche hot Electronic Injection, Used to erase and use Fowler-nordheim tuneling like EEPROM.

But the main difference is that,Flash can erase large or whole blocks of the chip, which reduces the complexity of the design., It can not be the redundant tansister In the eeprom unit, so it can achieve high integration, large capacity, and the floating gate technology of Flash is also different, the write speed is faster.

B. Nor differences between Nand

Addressing: each time a NAND reads data, it specifies the block address, page address, and column address. The column address is the start address of the read page. Each time the data is read into the page buffer, the I/O input address is then addressed in the buffer. In fact, the column address only specifies the starting address.

1. NAND is operated on pages as the basic unit. Writing data is first buffered in the page buffer. The data is first written here, and then written to the page after the command is written. Therefore, the entire page must be overwritten every time a byte is rewritten, because it only supports page writing, and if there are unerased parts in the page, it cannot be programmed, and the page must be blank before writing.

Therefore, the function of the NAND page buffer is to ensure that the page-based read and write operations on the chip are interfaces and bridges between I/O operations and chip operations, because the data is input from I/O and one byte at a time, it needs to be buffered.

2. Nor is the basic operation of byte. It can be written or read in byte, but erased is a sector operation.

To sum up, on the chip operation,Nand is much faster than nor, because NAND is page-operated and nor is byte-operated..

VII. application:
Nand is based on this structure: blocks and pages cannot be addressable in bytes. Page read/write itself relies on complicated internal strings and parallel conversions, so there are no many address pins, therefore, the addresses and data lines are shared, so the capacity can be very large.

Nor is the same as SRAM and can be stored randomly,No driver requiredTherefore, the address is limited, so the capacity is generally small,It is actually limited by the address line.

ThenThere are many bad NAND zones,

Based on the above points, there are many nor applications in the industrial field, especiallyProgramStorage, a small amount of data storage, etc.

in the consumption field, a large amount of data is stored and there are many NAND.