NAND or NOR flash memory is often used to store configuration data in numerous digital products, a task previously made possible by EEPROM or battery-powered static RAM.
| FactSnippet No. 975,798 |
20 Facts About NOR flash
2.
NOR-based flash has long erase and write times, but provides full address and data buses, allowing random access to any memory location.
| FactSnippet No. 975,799 |
3.
NAND NOR flash has achieved significant levels of memory density as a result of several major technologies that were commercialized during the late 2000s to early 2010s.
| FactSnippet No. 975,800 |
4.
Degradation or wear of the oxides is the reason why NOR flash memory has limited endurance, and data retention goes down with increasing degradation, since the oxides lose their electrically insulating characteristics as they degrade.
| FactSnippet No. 975,801 |
5.
NOR flash continues to be the technology of choice for embedded applications requiring a discrete non-volatile memory device.
| FactSnippet No. 975,802 |
6.
NAND NOR flash uses tunnel injection for writing and tunnel release for erasing.
| FactSnippet No. 975,803 |
7.
Hierarchical structure of NAND NOR flash starts at a cell level which establishes strings, then pages, blocks, planes and ultimately a die.
| FactSnippet No. 975,804 |
8.
Architecture of NAND NOR flash means that data can be read and programmed in pages, typically between 4 KiB and 16 KiB in size, but can only be erased at the level of entire blocks consisting of multiple pages.
| FactSnippet No. 975,805 |
9.
One limitation of NOR flash memory is that, it can be erased only a block at a time.
| FactSnippet No. 975,806 |
10.
In other words, flash memory offers random-access read and programming operations but does not offer arbitrary random-access rewrite or erase operations.
| FactSnippet No. 975,807 |
11.
Some file systems designed for NOR flash devices make use of this rewrite capability, for example Yaffs1, to represent sector metadata.
| FactSnippet No. 975,808 |
12.
NOR flash memory has an external address bus for reading and programming.
| FactSnippet No. 975,809 |
13.
For NOR flash memory, reading and programming are random-access, and unlocking and erasing are block-wise.
| FactSnippet No. 975,810 |
14.
NOR and NAND flash get their names from the structure of the interconnections between memory cells.
| FactSnippet No. 975,811 |
15.
The capacity scaling of NOR flash chips used to follow Moore's law because they are manufactured with many of the same integrated circuits techniques and equipment.
| FactSnippet No. 975,812 |
16.
Serial NOR flash is a small, low-power NOR flash memory that provides only serial access to the data - rather than addressing individual bytes, the user reads or writes large contiguous groups of bytes in the address space serially.
| FactSnippet No. 975,813 |
17.
When incorporated into an embedded system, serial NOR flash requires fewer wires on the PCB than parallel NOR flash memories, since it transmits and receives data one bit at a time.
| FactSnippet No. 975,814 |
18.
Since this type of SPI NOR flash lacks an internal SRAM buffer, the complete page must be read out and modified before being written back, making it slow to manage.
| FactSnippet No. 975,815 |
20.
The cost per gigabyte of NOR flash memory remains significantly higher than that of hard disks.
| FactSnippet No. 975,817 |