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I am designing a Vehicle Tracking device. I need a storage memory of 2Mb to 8Mb to store data from MCU. Based on what my MCU supports, I am planning to use SPI NOR Flash as a storage Device. As I know , NOR Flash is not recommended as a data storage device but it is commonly used as a Code storage device.

Considering the requirement of only 2Mb to 8Mb, is it okay to use NOR Flash as a data storage device?

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  • \$\begingroup\$ Could be easier to just use an SD card. It would be a bit more expensive but they handle auto-adjustment of sectors based on corruption and possibly wear leveling but don't quote me on that. For me it feels safer doing it that way as most of the flash chips I looked at were very basic in what they did behind the scenes. \$\endgroup\$ – Cameron Feb 18 '16 at 23:37
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Data Storage is the most common use of these SPI flash parts. As with all types of flash, you need to assess the number of erase cycles and the expected life-span of the device with respect to your own application requirements. When the raw part does not meet your requirements for erase cycles you can look at topics such as wear leveling.

In general, these parts are usually OK to use for data storage.

Edit

The reference you quoted is a 14 year old document that specifically compares parallel NOR, parallel NAND flash and DiskOnChip memory. The purpose of the document is to show how bad NAND and NOR flash is, and how wonderful DiskOnChip is. Since it is written by the makers of DiskOnChip it has to be considered to be rather biased. The statement that it makes "...disqualifying it from being used as a data storage device" is a very biased opinion. In the context of this discussion it is irrelevant anyway because you said you planned on using SPI NOR flash.

Many engineers (me included) have used SPI NOR flash for data storage. Whether it is suitable for your application only you know. But being able to program a 256 byte page in 0.8ms is sometimes fast enough.

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  • \$\begingroup\$ As I have read in few documents, due to slower erase & write operation, Nor Flash is not considered good for data storage. Page 9 , they have written :- "NOR offers good read performance but poor write and erase times, disqualifying it from being used as a data storage device." in link :- focus.ti.com/pdfs/omap/diskonchipvsnor.pdf \$\endgroup\$ – Oshi Feb 18 '16 at 22:51
  • \$\begingroup\$ @Rishi "poor" write times would be explicitly listed in the datasheet and may or may not be acceptable for your data collection rate, only you would know. \$\endgroup\$ – crasic Feb 18 '16 at 23:26
  • \$\begingroup\$ @Steve :- Thank you for a practical explanation Steve. I totally agree with your opinion. \$\endgroup\$ – Oshi Feb 19 '16 at 0:58
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NOR flash devices are easier to handle as compared to NAND devices. One drawback of NOR devices is slow erase.

A conclusion from this document:

Use of NOR devices is widespread in the industry. They offer an easy memory interface and are suitable for code execution, making them ideal for devices that do not need data storage. Their architecture makes them a good alternative in the range of 1MB to 4MB. NOR offers good read performance but poor write and erase times, disqualifying it from being used as a data storage device. However, as today’s devices become more and more sophisticated, they are expected to offer more features, richer programs and store more information locally. This requires larger capacities, both for code and data storage, and considerably faster erase/write times. NAND offers all of this, plus better prices in capacities ranging from 8MB to128MB. However, most engineers are reluctant to use it due to its non-standard interface and complicated management.

Although NOR flash is not recommended for data storage (fast R/W), it's simplicity to interface can be a boon for small designs that do not require fast R/W performance.

Overall, to answer your question yes, NOR flash is OK for your usage scenario. If your system will be powered up all the time, you can also use SPI RAM for faster R/W.

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  • \$\begingroup\$ Thank you Chetna. I cant use SPI RAM as the device has to be cost effective. \$\endgroup\$ – Oshi Feb 19 '16 at 0:11
  • \$\begingroup\$ @Rishi what SPI flash device are you using? \$\endgroup\$ – Chetan Bhargava Feb 19 '16 at 0:13
  • \$\begingroup\$ @Chetna :- I have not decided but it will be something like W25Q80DVSNIG TR. \$\endgroup\$ – Oshi Feb 19 '16 at 0:57
  • \$\begingroup\$ @Rishika you are good to go. \$\endgroup\$ – Chetan Bhargava Feb 20 '16 at 11:32

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