Detailed explanation of nonvolatile flash

Time:2021-1-19

Flash (flash or flash memory) was first introduced by Intel in 1988. It is a nonvolatile memory that can be quickly erased and programmed by electricity. Its speed is relative to EEPROM. Flash can be divided into nor flash and NAND flash from chip technology.

 

Nor Flash

NOR flash is characterized by on-chip execution (XIP), which allows applications to run directly in theMemory flashNo need to read the code into the system RAM. NOR flash has high transmission efficiency and high cost-effectiveness in small capacity of 1 ~ 4MB.

 

Nand Flash

NAND flash structure can provide high cell density, high storage density, and fast write and erase speed; however, its management and control is more complex.

 

Non volatile memory – NOR Flash

According to the bits of data transmission, nor flash can be divided into parallel and serial. Parallel nor flash transmits multiple bits of data each time, while serial nor flash transmits one bit of data each time. Parallel nor flash has faster transmission speed than serial nor flash.

 

Serial NOR Flash

The main interfaces are SPI, dual SPL and Quad SPI.

 

Parallel nor flash

The main interface has 8-bit, 16 bit, 8-bit / 16 bit optional data transmission mode.

 

Nonvolatile memory features of NOR Flash

Features: nor flash is a non-volatile memory, which is generally used for program code storage

Main thrust capacity 256kb-512mb

Serial: MCU with SPI port, IO port is less, low cost, small size, low speed, widely used.

Parallel: MCU with external bus, high speed, no internal flash, etc

Used in amr9, ARM11, a7, A8, A9 and other high-end platforms

 

Nonvolatile memory NAND flash features

Features: large capacity, fast writing speed and other advantages, suitable for big data storage

Main push capacity 512mb-8gb

Parallel: MUC with external storage controller, large amount of data, high speed

Used in amr9, ARM11, a7, A8, A9 and other high-end MCU; running wince / Linux / Android and other operating systems

Serial: MCU with SPI port, IO port less, low cost, small size

At present, only Gd (Beijing Zhaoyi) is producing related products, but we don’t push the storage of this product line



Application of flash



 

The difference between nor flash and NAND flash

NOR

1. Fast reading speed, slow writing speed

2. Slow erasure

3. About 100000 erasures

4. Small capacity 256kb-512mb

5. High price per unit capacity, suitable for small capacity program storage

6. It is not easy to produce bad blocks

NAND

1. Slow reading and fast writing

2. Fast erase speed ((1000:1)

3. About 1 million erasures

4. Large capacity 512mb-8gb

5. Low price per unit capacity, suitable for large capacity data storage

6. It is easy to produce bad blocks. It needs ECC to verify the memory chip. It is committed to providing customers with competitive products. It is a professional provider of storage solutions.   

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