Device Drivers

NuttX supports a variety of device drivers, which can be broadly divided in three classes:

• Character Device Drivers
• Block Device Drivers
• Specialized Device Drivers

Note

Device driver support depends on the in-memory, pseudo file system that is enabled by default.

Lower-half and upper-half

Drivers in NuttX generally work in two distinct layers:

• An upper half which registers itself to NuttX using a call such as register_driver() or register_blockdriver() and implements the corresponding high-level interface (read, write, close, etc.). implements the interface. This upper half calls into the lower half via callbacks.

• A “lower half” which is typically hardware-specific. This is usually implemented at the architecture or board level.