Using FileX with NOR Flash

Question

We are trying to use a Cypress/Infineon NOR flash SDF with FileX. We were able to get it working with LevelX but ran into performance and fragmentation issues. As a result we are trying to remove LevelX from the equation.

The following link https://wiki.st.com/stm32mcu/wiki/Introduction_to_FILEX#Example_2-_NOR_Flash_memory_interface implies FileX must be combined with LevelX to support NOR flash.

Other discussions regarding using FileX with NOR flash such as this one https://learn.microsoft.com/en-us/answers/questions/679922/about-the-upper-limit-of-the-number-of-file-genera.html also utilize LevelX in conjunction.

Is it true that LevelX must be used with FileX in order to support NOR flash?

Answer 1

Hi @tjr , it is possible to implement a FileX media driver to access the NOR flash directly, without using LevelX. But in that case, some flash blocks can become worn out sooner than other blocks. LevelX is used to solve this issue. It uses the flash blocks evenly to extend the device life.
If the application has few write operations, FileX can be used directly with NOR flash. In typical applications, it is recommended to use LevelX with FileX for NOR flash.

Answer 2

Caution about LevelX and FileX interaction. We are currently having a problem getting the interaction between the two correct. If you use FileX alone, it can use the entire flash. Using LevelX is of course, preferable, but you want to format FileX with one fewer erasable unit than LevelX controls, so it can relocate sectors appropriately. We are currently having difficulty configuring that in Synergy and Renesas. Your tools may be better.