Hi Thomas, According to drivers/mtd/README.txt the NAND support is only partial because there is not a FS to handle it correctly.
Normally for NAND you will need to scan the NAND to update the bad block table during the boot (could be on NuttX or in a bootloader) to guarantee the FS will be use a bad block (remember that NAND normally comes with bad blocks from factory). Note that the nand_devscan() function at mtd_nand.c just try to retrieve this information, it doesn't update the Bad Block Table. Also your MCU needs to have some support in hardware to communicate with NAND (parallel model), for SPI NAND it is not necessary. It appears that currently only SAMA5 has support to it. Of course, this should be a very useful thing to have on NuttX because as application become more complex we need more space for them. What MCU are you planing to use? BR, Alan On 9/25/20, Thomas Axelsson <thomas.axels...@actia.se> wrote: > Hi, > > I'm trying to understand what level of NAND memory support currently exists > in NuttX. The intention is to read and write files on the NAND memory. > > I have found CONFIG_MTD_NAND and there seems to be a NAND driver for the > SAMA5 built-in NAND. All other MTD drivers appear to be for NOR? The > intention is to use a Winbond W25N NAND memory, but I'm assuming the SAMA5 > driver will be closer to what I need than the W25QxxxJV NOR driver (NAND vs > NOR)? > > Regarding a file system, the NuttX About page mentions "NXFFS. The tiny > NuttX wear-leveling FLASH file system." and there is also the option to > enable littlefs. > > https://github.com/ARMmbed/littlefs/issues/11 indicates that one wants an > FTL below littlefs. Going by the existence of CONFIG_FTL_READAHEAD and > CONFIG_WRITEBUFFER, it seems that the FTL is integrated in MTD in NuttX? > > Is SMART File System (CONFIG_FS_SMARTFS) related to the "Really Tiny > (SMART) Flash" (CONFIG_MTD_SMART) option? The latter says that it is only > usable for really small memories. > > Thomas Axelsson > SW Developer > ACTIA Nordic AB (part of ACTIA Group) > > Mail: thomas.axels...@actia.se<mailto:thomas.axels...@actia.se> > Web: www.actia.se<http://www.actia.se/> > >
