You can either: 1. Or expose FRAM as a tmpfs through mount pointer 2. If you want to use FRAM as PSRAM, you can add FRAM to the system heap with kmm_addregion 3. If you want to use FRAM as an separated heap, you can call mm_initialize, mm_malloc and mm_free
https://github.com/apache/incubator-nuttx/blob/master/include/nuttx/mm/mm.h#L155-L156 depending on your case, you may select one or several approaches together. On Wed, Jul 27, 2022 at 4:24 PM <michael.sch...@mdc-service.de> wrote: > Dear all, > > we are in the process of porting Nuttx to our new EsPiFF-V3 board. Basic > Nuttx with nsh is working already. This is a board with a ESP32-WROVER > module, and has additional SPI-connected FRAM (2kB to 256kB possible). > How could the SPI-connected FRAM be integrated into Nuttx? > > - the FRAM is as fast as the ESP32-SPI PSRAM, and it should offer the > application to store process variables and not lost it when power down. > Best would be, when it can be addressed with malloc() or similar > function for the user. > > - SPI-based EEPROMs have traditionally a mount point in the file system, > and are exposed as a device driver to the user. I could implement it in > this way, but as such, the attractive variable assignment in RAM would > not be available. > > Could the existing HiMem driver on the ESP32 with bank switching be > extended, to also support FRAM for use with malloc? Our FRAM is > connected to a different SPI bus then the PS-RAM. > > Or is it not a good idea to expose the SPI-FRAM via malloc, and we > should use a device driver and let the user access the content via a > mount point in the file system? > > Best regards, > Michael > >
