Architecture-Specific Code
^^^^^^^^^^^^^^^^^^^^^^^^^^
Table of Contents
^^^^^^^^^^^^^^^^^
o Architecture-Specific Code
o Summary of Files
o Supported Architectures
o Configuring NuttX
Architecture-Specific Code
^^^^^^^^^^^^^^^^^^^^^^^^^^
The NuttX configuration consists of:
o Processor architecture specific files. These are the files contained
in the arch/<arch-name>/ directory discussed in this README.
o Chip/SoC specific files. Each processor processor architecture
is embedded in chip or System-on-a-Chip (SoC) architecture. The
full chip architecture includes the processor architecture plus
chip-specific interrupt logic, general purpose I/O (GIO) logic, and
specialized, internal peripherals (such as UARTs, USB, etc.).
These chip-specific files are contained within chip-specific
sub-directories in the arch/<arch-name>/ directory and are selected
via the CONFIG_ARCH_name selection
o Board specific files. In order to be usable, the chip must be
contained in a board environment. The board configuration defines
additional properties of the board including such things as
peripheral LEDs, external peripherals (such as network, USB, etc.).
These board-specific configuration files can be found in the
configs/<board-name>/ sub-directories.
This README will address the processor architecture specific files
that are contained in the arch/<arch-name>/ directory. The file
include/nuttx/arch.h identifies all of the APIs that must
be provided by this architecture specific logic. (It also includes
arch/<arch-name>/arch.h as described below).
Directory Structure
^^^^^^^^^^^^^^^^^^^
The arch directory contains architecture specific logic. The complete
board port in is defined by the architecture-specific code in this
directory (plus the board-specific configurations in the config/
subdirectory). Each architecture must provide a subdirectory <arch-name>
under arch/ with the following characteristics:
<arch-name>/
|-- include/
| |--<chip-name>/
| | `-- (chip-specific header files)
| |--<other-chips>/
| |-- arch.h
| |-- irq.h
| `-- types.h
`-- src/
|--<chip-name>/
| `-- (chip-specific source files)
|--<other-chips>/
|-- Makefile
`-- (architecture-specific source files)
Summary of Files
^^^^^^^^^^^^^^^^
include/<chip-name>/
This sub-directory contains chip-specific header files.
include/arch.h
This is a hook for any architecture specific definitions that may
be needed by the system. It is included by include/nuttx/arch.h
include/types.h
This provides architecture/toolchain-specific definitions for
standard types. This file should typedef:
sbyte, ubyte, uint8, boolean, sint16, uint16, sint32, uint32
and
sint64, uint64
if the architecture supports 64-bit integers.
irqstate_t
Must be defined to the be the size required to hold the interrupt
enable/disable state.
This file will be included by include/sys/types.h and be made
available to all files.
include/irq.h
This file needs to define some architecture specific functions (usually
inline if the compiler supports inlining) and structure. These include:
- struct xcptcontext. This structures represents the saved context
of a thread.
- irqstate_t irqsave(void) -- Used to disable all interrupts.
- void irqrestore(irqstate_t flags) -- Used to restore interrupt
enables to the same state as before irqsave was called.
This file must also define NR_IRQS, the total number of IRQs supported
by the board.
src/<chip-name>/
This sub-directory contains chip-specific source files.
src/Makefile
This makefile will be executed to build the targets src/libup.a and
src/up_head.o. The up_head.o file holds the entry point into the system
(power-on reset entry point, for example). It will be used in
the final link with libup.a and other system archives to generate the
final executable.
Supported Architectures
^^^^^^^^^^^^^^^^^^^^^^^
arch/sim
A user-mode port of NuttX to the x86 Linux platform is available.
The purpose of this port is primarily to support OS feature developement.
This port does not support interrupts or a real timer (and hence no
round robin scheduler) Otherwise, it is complete.
arch/c5471
TI TMS320C5471 (also called TMS320DM180 or just C5471).
NuttX operates on the ARM7 of this dual core processor. This port
complete, verified, and included in the NuttX release 0.1.1.
arch/dm320
TI TMS320DM320 (also called just DM320).
NuttX operates on the ARM9EJS of this dual core processor. This port
complete, verified, and included in the NuttX release 0.2.1.
arch/m68322
A work in progress.
arch/pjrc-8051
8051 Microcontroller. This port is not quite ready for prime time.
Other ports for the for the TI TMS320DM270 and for MIPS are in various states
of progress
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