Hi, Is there any recomended basic translation layer for NAND flash for FreeRTOS+FAT? 1. Bad sector list 2. Wear levering 3. Error detection 4. Redundant FAT Purpose is firmware storage and logging of non-critical data. Thanks Rasty
It would give me headaches to write an efficient and fast and low-RAM FAT-driver for NAND. You have to deal with an ERASE size of more than one block. Erasing means: writing “all ones”. When you want to change one 512-block, you probably have to read/erase/write a much larger block of e.g. 2 or 4 KB. For most projects where +FAT is needed, I would use an SD-card. SD-cards are optimised for FAT tables if you store the table after an offset of 4MB from the start. That part may be re-written much more often than any other part of the card. As far as I know, a NAND flash chip has homogeneous memory, which can be re-written N times. You will have to write all logic that an SD-card will do for you. You will also have to deal with bad sectors: mark them as bad and repair a file system. Depending on the data needs, you can also decide not to use a file system on NAND. I hope that someone else has a more optimistic view on this 🙂 Hein
Hi Hein, You’re right . SD card or eMMC is simple and reliable option, but not every MCU can load/boot from eMMC. Some commercial file systems provide that layer. Flash block handling is major IP. Thank you very much for the reply. Rasty
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