Device Driver

Devices drivers for the most popular devices are already available for µC/FS. If you use a particular device for which no driver exist, you should read this section to understand how to build your own driver.

A device driver is registered with the file system by passing a pointer to its API structure as the first parameter of FS_DevDrvAdd(). The API structure, FS_DEV_API, includes pointers to eight functions used to control and access the device:

const  FS_DEV_API  FSDev_#### = {
    FSDev_####_NameGet,
    FSDev_####_Init,
    FSDev_####_Open,
    FSDev_####_Close,
    FSDev_####_Rd,
#if (FS_CFG_RD_ONLY_EN == DEF_DISABLED)
    FSDev_####_Wr,
#endif
    FSDev_####_Query,
    FSDev_####_IO_Ctrl
};

The functions which must be implemented are listed and described in the table below.. The first two functions, NameGet() and Init(), act upon the driver as a whole; neither should interact with any physical devices. The remaining functions act upon individual devices, and the first argument of each is a pointer to a FS_DEV structure which holds device information, including the unit number which uniquely identifies the device unit (member UnitNbr).