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|
<html>
<head>
<title>NuttX Porting Guide</title>
<meta name="author" content="Gregory Nutt">
</head>
<body background="backgd.gif">
<hr><hr>
<table width ="100%">
<tr align="center" bgcolor="#e4e4e4">
<td>
<h1><big><font color="#3c34ec">
<i>NuttX RTOS Porting Guide</i>
</font></big></h1>
<p>Last Updated: May 28, 2009</p>
</td>
</tr>
</table>
<hr><hr>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1>Table of Contents</h1>
</td>
</tr>
</table>
<ul>
<a href="#Introduction">1.0 Introduction</a><br>
<a href="#DirectoryStructure">2.0 Directory Structure</a>
<ul>
<a href="#DirStructDocumentation">2.1 Documentation</a></br>
<a href="#DirStructArch">2.2 arch/</a>
<ul>
<a href="#archdirectorystructure">2.2.1 Subdirectory Structure</a><br>
<a href="#summaryofarchfiles">2.2.2 Summary of Files</a><br>
<a href="#supportedarchitectures">2.2.3 Supported Architectures</a>
</ul>
<a href="#DirStructConfigs">2.3 configs/</a>
<ul>
<a href="#configsdirectorystructure">2.3.1 Subdirectory Structure</a><br>
<a href="#summaryofconfigfiles">2.3.2 Summary of Files</a>
<ul>
<a href="#boardlogic">2.3.2.1 Board Specific Logic</a><br>
<a href="#boardconfigsubdirs">2.3.2.2 Board Specific Configuration Sub-Directories</a>
</ul>
<a href="#supportedboards">2.3.3 Supported Boards</a>
</ul>
<a href="#DirStructDrivers">2.4 drivers/</a><br>
<a href="#DirStructExamples">2.5 examples/</a><br>
<a href="#DirStructFs">2.6 fs/</a><br>
<a href="#DirStructGraphics">2.7 graphics/</a><br>
<a href="#DirStructInclude">2.8 include/</a><br>
<a href="#DirStructLib">2.9 lib/</a><br>
<a href="#DirStructMm">2.10 mm/</a><br>
<a href="#DirStructNet">2.11 net</a><br>
<a href="#DirStructNetUtils">2.12 netutils</a><br>
<a href="#DirStructSched">2.13 sched/</a><br>
<a href="#DirStructTools">2.14 tools/</a><br>
<a href="#topmakefile">2.15 Makefile</a>
</ul>
<a href="#configandbuild">3.0 Configuring and Building</a>
<ul>
<a href="#configuringnuttx">3.1 Configuring NuttX</a><br>
<a href="#buildingnuttx">3.2 Building NuttX</a>
</ul>
<a href="#ArchAPIs">4.0 Architecture APIs</a>
<ul>
<a href="#imports">4.1 APIs Exported by Architecture-Specific Logic to NuttX</a>
<ul>
<a href="#upinitialize">4.1.1 <code>up_initialize()</code></a><br>
<a href="#upidle">4.1.2 <code>up_idle()</code></a><br>
<a href="#upinitialstate">4.1.3 <code>up_initial_state()</code></a><br>
<a href="#upcreatestack">4.1.4 <code>up_create_stack()</code></a><br>
<a href="#upusestack">4.1.5 <code>up_use_stack()</code></a><br>
<a href="#upreleasestack">4.1.6 <code>up_release_stack()</code></a><br>
<a href="#upunblocktask">4.1.7 <code>up_unblock_task()</code></a><br>
<a href="#upblocktask">4.1.8 <code>up_block_task()</code></a><br>
<a href="#upreleasepending">4.1.9 <code>up_release_pending()</code></a><br>
<a href="#upreprioritizertr">4.1.10 <code>up_reprioritize_rtr()</code></a><br>
<a href="#_exit">4.1.11 <code>_exit()</code></a><br>
<a href="#upassert">4.1.12 <code>up_assert()</code></a><br>
<a href="#upschedulesigaction">4.1.13 <code>up_schedule_sigaction()</code></a><br>
<a href="#upallocateheap">4.1.14 <code>up_allocate_heap()</code></a><br>
<a href="#upinterruptcontext">4.1.15 <code>up_interrupt_context()</code></a><br>
<a href="#updisableirq">4.1.16 <code>up_disable_irq()</code></a><br>
<a href="#upenableirq">4.1.17 <code>up_enable_irq()</code></a><br>
<a href="#upprioritizeirq">4.1.18 <code>up_prioritize_irq()</code></a></br>
<a href="#upputc">4.1.19 <code>up_putc()</code></a>
</ul>
<a href="#exports">4.2 APIs Exported by NuttX to Architecture-Specific Logic</a>
<ul>
<a href="#osstart">4.2.1 <code>os_start()</code></a><br>
<a href="#listmgmt">4.2.2 OS List Management APIs</a><br>
<a href="#schedprocesstimer">4.2.3 <code>sched_process_timer()</code></a><br>
<a href="#irqdispatch">4.2.4 <code>irq_dispatch()</code></a>
</ul>
<a href="#ledsupport">4.3 LED Support</a>
<ul>
<a href="#ledheaders">4.3.1 Header Files</a><br>
<a href="#leddefinitions">4.3.2 LED Definitions</a><br>
<a href="#ledapis">4.3.3 Common LED interfaces</a>
</ul>
</ul>
<a href="#NxFileSystem">5.0 NuttX File System</a><br>
<a href="#DeviceDrivers">6.0 NuttX Device Drivers</a><br>
<ul>
<a href="#chardrivers">6.1 Character Device Drivers</a><br>
<a href="#blockdrivers">6.2 Block Device Drivers</a><br>
<a href="#blockdrivers">6.3 Specialized Device Drivers</a>
<ul>
<a href="#ethdrivers">6.3.1 Ethernet Device Drivers</a><br>
<a href="#spidrivers">6.3.2 SPI Device Drivers</a><br>
<a href="#i2cdrivers">6.3.3 I2C Device Drivers</a><br>
<a href="#serialdrivers">6.3.4 Serial Device Drivers</a>
</ul>
</ul>
<a href="#apndxconfigs">Appendix A: NuttX Configuration Settings</a><br>
<a href="#apndxtrademarks">Appendix B: Trademarks</a>
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1>1.0 <a name="Introduction">Introduction</a></h1>
</td>
</tr>
</table>
<p><b>Overview</b>
This document provides and overview of the NuttX build and configuration
logic and provides hints for the incorporation of new processor/board architectures
into the build.
</p>
<p>
See also <code>arch/README.txt</code> and <code>configs/README.txt</code>.
</p>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1>2.0 <a name="DirectoryStructure">Directory Structure</a></h1>
</td>
</tr>
</table>
<p>
<b>Directory Structure</b>.
The general directly layout for NuttX is very similar to the directory structure
of the Linux kernel -- at least at the most superficial layers.
At the top level is the main makefile and a series of sub-directories identified
below and discussed in the following paragraphs:
</p>
<ul><pre>
.
|-- <a href="#topmakefile">Makefile</a>
|-- <a href="#DirStructDocumentation">Documentation</a>
| `-- <i>(documentation files)</i>/
|-- <a href="#DirStructArch">arch</a>/
| |-- <i><arch-name></i>/
| | |-- include/
| | | |--<i><chip-name></i>/
| | | | `-- <i>(chip-specific header files)</i>
| | | |--<i><other-chips></i>/
| | | `-- <i>(architecture-specific header files)</i>
| | `-- src/
| | |--<i><chip-name></i>/
| | | `-- <i>(chip-specific source files)</i>
| | |--<i><other-chips></i>/
| | `-- <i>(architecture-specific source files)</i>
| `-- <i><other-architecture directories></i>/
|-- <a href="#DirStructConfigs">configs</a>/
| |-- <i><board-name></i>/
| | |-- include/
| | | `-- <i>(other board-specific header files)</i>
| | |-- src/
| | | `-- <i>(board-specific source files)</i>
| | |---<i><config-name></i>/
| | | `-- <i>(board configuration-specific source files)</i>
| | `---<i>(other configuration sub-directories for this board)</i>/
| `-- <i><(other board directories)></i>/
|-- <a href="#DirStructDrivers">drivers</a>/
| |-- Makefile
| |-- <i>(driver-specific sub-directories)/</i>
| | `-- <i>(driver-specific source files)</i>
| `-- <i>(common driver source files)</i>
|-- <a href="#DirStructExamples">examples</a>/
| `-- <i>(example)</i>/
| |-- Makefile
| `-- <i>(example source files)</i>
|-- <a href="#DirStructFs">fs</a>/
| |-- Makefile
| |-- <i>(file system-specific sub-directories)</i>/
| | `-- <i>(file system-specific source files)</i>
| `-- <i>(common file system source files)</i>
|-- <a href="#DirStructGraphics">graphics</a>/
| |-- Makefile
| |-- <i>(feature-specific sub-directories)</i>/
| | `-- <i>(feature-specific source files library source files)</i>
| `-- <i>(common graphics-related source files)</i>
|-- <a href="#DirStructInclude">include</a>/
| |-- <i>(standard header files)</i>
| |-- <i>(standard include sub-directories)</i>
| | `-- <i>(more standard header files)</i>
| |-- <i>(non-standard include sub-directories)</i>
| `-- <i>(non-standard header files)</i>
|-- <a href="#DirStructLib">lib</a>/
| |-- Makefile
| `-- <i>(lib source files)</i>
|-- <a href="#DirStructMm">mm</a>/
| |-- Makefile
| `-- <i>(memory management source files)</i>
|-- <a href="#DirStructNet">net</a>/
| |-- Makefile
| |-- uip/
| | `-- <i>(uip source files)</i>
| `-- <i>(BSD socket source files)</i>
|-- <a href="#DirStructNetUtils">netutils</a>/
| |-- Makefile
| |-- <i>(network feature sub-directories)</i>/
| | `-- <i>(network feature source files)</i>
| `-- <i>(netutils common files)</i>
|-- <a href="#DirStructSched">sched</a>/
| |-- Makefile
| `-- <i>(sched source files)</i>
`-- <a href="#DirStructTools">tools</a>/
`-- <i>(miscellaneous scripts and programs)</i>
</pre></ul>
<p>
<b>Configuration Files</b>.
The NuttX configuration consists of:
</p>
<ul>
<li>
<i>Processor architecture specific files</i>.
These are the files contained in the <code>arch/</code><i><arch-name></i><code>/</code> directory
and are discussed in a paragraph <a href="#archdirectorystructure">below</a>.
</li>
<li>
<i>Chip/SoC specific files</i>.
Each processor processor architecture is embedded in chip or <i>System-on-a-Chip</i> (SoC) architecture.
The full chip architecture includes the processor architecture plus chip-specific interrupt logic,
clocking logic, general purpose I/O (GIO) logic, and specialized, internal peripherals (such as UARTs, USB, etc.).
<p>
These chip-specific files are contained within chip-specific sub-directories in the
<code>arch/</code><i><arch-name></i><code>/</code> directory and are selected via
the <code>CONFIG_ARCH_name</code> selection.
</p>
</li>
<li>
<i>Board specific configurations</i>.
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.).
<p>
These board-specific configuration files can be found in the
<code>configs/</code><i><board-name></i><code>/</code> sub-directories and are discussed
in a paragraph <a href="#configsdirectorystructure">below</a>.
</p>
</li>
</ul>
<h2>2.1 <a name="DirStructDocumentation">Documentation</a></h2>
<p>
General documentation for the NuttX OS resides in this directory.
</p>
<h2>2.2 <a name="DirStructArch">arch</a></h2>
<h3><a name="archdirectorystructure">2.2.1 Subdirectory Structure</a></h3>
<p>
This directory contains several sub-directories, each containing
architecture-specific logic.
The task of porting NuttX to a new processor consists of
add a new subdirectory under <code>arch/</code> containing logic specific
to the new architecture.
The complete board port in is defined by the architecture-specific code in this
directory (plus the board-specific configurations in the <code>config/</code>
subdirectory).
Each architecture must provide a subdirectory, <i><arch-name></i>
under <code>arch/</code> with the following characteristics:
</p>
<ul><pre>
<i><arch-name></i>/
|-- include/
| |--<i><chip-name></i>/
| | `-- <i>(chip-specific header files)</i>
| |--<i><other-chips></i>/
| |-- arch.h
| |-- irq.h
| |-- types.h
| `-- limits.h
`-- src/
|--<i><chip-name></i>/
| `-- <i>(chip-specific source files)</i>
|--<i><other-chips></i>/
|-- Makefile
`-- <i>(architecture-specific source files)</i>
</pre></ul>
<h3><a name="summaryofarchfiles">2.2.2 Summary of Files</a></h3>
<ul>
<li>
<code>include/</code><i><chip-name></i><code>/</code>
This sub-directory contains chip-specific header files.
</li>
<li>
<code>include/arch.h</code>:
This is a hook for any architecture specific definitions that may
be needed by the system. It is included by <code>include/nuttx/arch.h</code>.
</li>
<li>
<code>include/types.h</code>:
This provides architecture/toolchain-specific definitions for
standard types. This file should <code>typedef</code>:
<ul><code>
sbyte, ubyte, uint8, boolean, sint16, uint16, sint32, uint32
</code></ul>
<p>and if the architecture supports 64-bit integers</p>
<ul><code>
sint64, uint64
</code></ul>
<p>
and finally
</p>
<ul><code>
irqstate_t
</code></ul>
<p>
Must be defined to the be the size required to hold the interrupt
enable/disable state.
</p>
<p>
This file will be included by include/sys/types.h and be made
available to all files.
</p>
</li>
<li>
<code>include/irq.h</code>:
This file needs to define some architecture specific functions (usually
inline if the compiler supports inlining) and structure. These include:
<ul>
<li>
<code>struct xcptcontext</code>:
This structures represents the saved context of a thread.
</li>
<li>
<code>irqstate_t irqsave(void)</code>:
Used to disable all interrupts.
</li>
<li>
<code>void irqrestore(irqstate_t flags)<code>:
Used to restore interrupt enables to the same state as before <code>irqsave()</code> was called.
</li>
</ul>
<p>
This file must also define <code>NR_IRQS</code>, the total number of IRQs supported
by the board.
</p>
</li>
<li>
<code>src/</code><i><chip-name></i><code>/</code>
This sub-directory contains chip-specific source files.
</li>
<li>
<code>src/Makefile</code>:
This makefile will be executed to build the targets <code>src/libup.a</code> and
<code>src/up_head.o</code>. The <code>up_head.o</code> file holds the entry point into the system
(power-on reset entry point, for example). It will be used in
the final link with <code>libup.a</code> and other system archives to generate the
final executable.
</li>
<li>
<i>(architecture-specific source files)</i>.
The file <code>include/nuttx/arch.h</code> identifies all of the APIs that must
be provided by the architecture specific logic. (It also includes
<code>arch/</code><i><arch-name></i><code>/arch.h</code> as described above).
</li>
</ul>
<h3><a name="supportedarchitectures">2.2.3 Supported Architectures</a></h3>
<p>
<b>Archictecture- and Chip-Specific Directories</b>.
All processor architecture-specific directories are maintained in sub-directories of
the <code>arch/</code> directory.
Different chips or SoC's may implement the same processor core.
Chip-specific logic can be found in sub-directories under the architecture
directory.
Current architecture/chip directories are summarized below:
</p>
<ul>
<li><code>arch/sim</code>:
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.
</li>
<p>NOTE: This target will not run on Cygwin probably for many reasons but
first off because it uses some of the same symbols as does cygwind.dll.
</p>
<li><code>arch/arm</code>:
This directory holds common ARM architectures. At present, this includes
the following subdirectories:
<ul>
<li><code>arch/arm/include</code> and <code>arch/arm/src/common</code>:
Common ARM logic.
</li>
<li><code>arch/arm/include/c5471</code> and <code>arch/arm/src/c5471</code>:
TI TMS320C5471 (also called TMS320DM180 or just C5471).
NuttX operates on the ARM7 of this dual core processor.
This port is complete, verified, and included in the NuttX release 0.1.1.
</li>
<li><code>arch/arm/include/dm320</code> and <code>arch/arm/src/dm320</code>:
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.
</li>
<li><code>arch/arm/include/lpc214x</code> and <code>arch/arm/src/lpc214x</code>:
These directories provide support for NXP LPC214x family of
processors.
STATUS: This port is in progress and should be available in the
nuttx-0.2.5 release.
</li>
</ul>
</li>
<li><code>configs/mcu123-lpc214x</code>:
The mcu123.com lpc214x development board.
This is a work in progress.
</li>
<li><code>arch/m68322</code>
A work in progress.
</li>
<li><code>arch/pjrc-8051</code>:
8051 Microcontroller. This port is not quite ready for prime time.
</li>
<li><code>arch/z16f</code>:
Zilog z16f Microcontroller.
This port uses the Zilog z16f2800100zcog Development Kit.
This port was released with nuttx-0.3.7.
</li>
<li><code>arch/z80</code>:
This directory holds 8-bit ZiLOG architectures. At present, this includes the
Zilog z80, ez80Acclaim! and z8Encore! Microcontrollers.
<ul>
<li><code>arch/z80/include</code> and <code>arch/z80/src/common</code>:
Common logic.
</li>
<li><code>arch/z80/include/z80</code> and <code>arch/z80/src/z80</code>:
The Z80 port was released in nuttx-0.3.6 has been verified using only a
z80 instruction simulator.
The set simulator can be found in the NuttX CVS at
http://nuttx.cvs.sourceforge.net/nuttx/misc/sims/z80sim.
This port also uses the SDCC toolchain (http://sdcc.sourceforge.net/")
(verified with version 2.6.0 and 2.7.0).
</li>
<li><code>arch/z80/include/ez80</code> and <code>arch/z80/src/ez80</code>:
The ez80Acclaim! port uses the ZiLOG ez80f0910200kitg development kit, eZ80F091 part,
with the Zilog ZDS-II Windows command line tools.
The development environment is Cygwin under WinXP.
This is a work in progress. Verified ez80 support will be announced in a future NuttX release.
</li>
<li><code>arch/z80/include/z8</code> and <code>arch/z80/src/z8</code>:
The Z8Encore! port uses either the ZiLOG z8encore000zco development kit, Z8F6403 part,
or the z8f64200100kit development kit, Z8F6423 part with the Zilog ZDS-II Windows command line
tools. The development environment is Cygwin under WinXP.
The initial release, verified only on the ZDS-II ez8 simulator, was released in nuttx-0.3.9.
</li>
</ul>
</li>
</ul>
<p>
<b>Deprecated Architecture Directories</b>.
The following architecture directories are deprecated. They have been
replaced by the logic in <code>arm/arm</code> and will deleted when
<code>arch/arm</code> is fully verified.
</p>
<ul>
<li><code>arch/c5471</code>:
Replaced with <code>arch/arm/include/c5471</code> and
<code>arch/arm/src/c5471<code>.
</li>
<li><code>arch/dm320</code>:
Replaced with <code>arch/arm/include/dm320</code> and
<code>arch/arm/src/dm320<code>.
</li>
</ul>
<p>
Other ports for the for the TI TMS320DM270 and for MIPS are in various states
of progress
</p>
<h2>2.3 <a name="DirStructConfigs">configs</a></h2>
<p>
The <code>configs/</code> subdirectory contains configuration data for each board.
These board-specific configurations plus the architecture-specific configurations in
the <code>arch/</code> subdirectory complete define a customized port of NuttX.
</p>
<h3><a name="configsdirectorystructure">2.3.1 Subdirectory Structure</a></h3>
<p>
The configs directory contains board specific configuration files. Each board must
provide a subdirectory <board-name> under <code>configs/</code> with the following characteristics:
</p>
<ul><pre>
<i><board-name></i>
|-- include/
| |-- board.h
| `-- <i>(board-specific header files)</i>
|-- src/
| |-- Makefile
| `-- <i>(board-specific source files)</i>
|-- <i><config1-dir></i>
| |-- Make.defs
| |-- defconfig
| `-- setenv.sh
|-- <i><config2-dir></i>
| |-- Make.defs
| |-- defconfig
| `-- setenv.sh
| ...
`-- <i>(other board-specific configuration sub-directories)</i>/
</pre></ul>
<h3><a name="summaryofconfigfiles">2.3.2 Summary of Files</a></h3>
<h4><a name="boardlogic">2.3.2.1 Board Specific Logic</a></h4>
<ul>
<li>
<code>include/</code>:
This directory contains board specific header files.
This directory will be linked as <code>include/arch/board</code> at configuration time
and can be included via <code>#include <arch/board/header.h></code>.
These header file can only be included by files in <code>arch/</code><i><arch-name></i><code>/include/</code>
and <code>arch/</code><i><arch-name></i><code>/src/</code>.
</li>
<li>
<code>src/</code>:
This directory contains board specific drivers.
This directory will be linked as <config>arch/</code><i><arch-name></i><code>/src/board</config> at configuration
time and will be integrated into the build system.
</li>
<li>
<code>src/Makefile</code>:
This makefile will be invoked to build the board specific drivers.
It must support the following targets: <code>libext$(LIBEXT)</code>, <code>clean</code>, and <code>distclean</code>.
</li>
</ul>
<h4><a name="boardconfigsubdirs">2.3.2.2 Board Specific Configuration Sub-Directories</a></h4>
<p>
The <code>configs/</code><i><board-name></i><code>/</code> sub-directory holds all of the
files that are necessary to configure Nuttx for the particular board.
A board may have various different configurations using the common source files.
Each board configuration is described by three files: <code>Make.defs</code>, <code>defconfig</code>, and <code>setenv.sh</code>.
Typically, each set of configuration files is retained in a separate configuration sub-directory
(<i><config1-dir></i>, <i><config2-dir></i>, .. in the above diagram).
The procedure for configuring NuttX is described <a href="#configuringnuttx">below</a>,
This paragraph will describe the contents of these configuration files.
</p>
<ul>
<li>
<code>Make.defs</code>: This makefile fragment provides architecture and
tool-specific build options. It will be included by all other
makefiles in the build (once it is installed). This make fragment
should define:
<ul>
<li>Tools: CC, LD, AR, NM, OBJCOPY, OBJDUMP</li>
<li>Tool options: CFLAGS, LDFLAGS</li>
<li>COMPILE, ASSEMBLE, ARCHIVE, CLEAN, and MKDEP macros</li>
</ul>
<p>
When this makefile fragment runs, it will be passed TOPDIR which
is the path to the root directory of the build. This makefile
fragment may include ${TOPDIR}/.config to perform configuration
specific settings. For example, the CFLAGS will most likely be
different if CONFIG_DEBUG=y.
</p>
</li>
<li>
<code>defconfig</code>: This is a configuration file similar to the Linux
configuration file. In contains variable/value pairs like:
<ul>
<li><code>CONFIG_VARIABLE</code>=value</li>
</ul>
<p>
This configuration file will be used at build time:
</p>
<ol>
<li>As a makefile fragment included in other makefiles, and</li>
<li>to generate <code>include/nuttx/config.h</code> which is included by
most C files in the system.</li>
</ol>
</li>
<li>
<code>setenv.sh</code>: This is a script that you can include that will be installed at
the toplevel of the directory structure and can be sourced to set any
necessary environment variables.
</li>
</ul>
<h3><a name="supportedboards">2.3.3 Supported Boards</a></h3>
<p>
All of the specific boards supported by NuttX are identified below.
These are the specific <i><board-name></i>'s that may be used to configure NuttX
as described <a href="#configuringnuttx">below</a>.
</p>
<ul>
<li><code>configs/c5471evm</code>:
This is a port to the Spectrum Digital C5471 evaluation board. The
C5471 is a dual core processor from TI with an ARM7TDMI general purpose
processor and a c54 SDP. NuttX runs on the ARM core and is built with
with a GNU arm-elf toolchain* under Linux or Cygwin.
This port is complete, verified, and included in the NuttX release.
</li>
<li><code>configs/ez80f0910200kitg</code>
ez80Acclaim! Microcontroller. This port use the Zilog ez80f0910200kitg
development kit, eZ80F091 part, and the Zilog ZDS-II Windows command line
tools. The development environment is Cygwin under WinXP.
</li>
<li><code>configs/m68322evb</code>:
This is a work in progress for the venerable m68322evb board from
Motorola.
</li>
<li><code>configs/mcu123-lpc214x</code>:
This port is for the NXP LPC2148 as provided on the mcu123.com
lpc214x development board.
This OS is also built with the arm-elf toolchain* under Linux or Cygwin.
The port supports serial, timer0, spi, and usb.
</li>
<li><code>configs/ntosd-dm320</code>:
This port uses the Neuros OSD with a GNU arm-elf toolchain* under Linux or Cygwin.
See <a href="http://wiki.neurostechnology.com/index.php/Developer_Welcome">Neuros Wiki</a>
for futher information.
NuttX operates on the ARM9EJS of this dual core processor.
STATUS: This port is code complete, verified, and included in the
NuttX 0.2.1 release.
</li>
<li><code>configs/olimex-strp711</code>:
This port uses the Olimex STR-P711 board arm-elf toolchain* under Linux or Cygwin.
See the <a href="http://www.olimex.com/dev/str-p711.html">Olimex</a> web site
for futher information.
STATUS: Coding for the basic port -- serial console and system timer -- is complete
but untested to problems I am having using OpenOCD with a wiggler clone JTAG.
</li>
<li><code>configs/pjrc-8051</code>:
8051 Microcontroller. This port uses the PJRC 87C52 development system
and the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain under Linux or Cygwin.
This port is not quite ready for prime time.
</li>
<li><code>configs/sim</code>:
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.
</li>
<li><code>configs/us7032evb1</code>:
This is a port of the Hitachi SH-1 on the Hitachi SH-1/US7032EVB1 board.
STATUS: Work has just began on this port.
</li>
<li><code>configs/xtrs</code>:
TRS80 Model 3. This port uses a vintage computer based on the Z80.
An emulator for this computer is available to run TRS80 programs on a
linux platform (http://www.tim-mann.org/xtrs.html).
</li>
<li><code>configs/z16f2800100zcog</code>
z16f Microcontroller.
This port use the Zilog z16f2800100zcog development kit and the
Zilog ZDS-II Windows command line tools.
The development environment is Cygwin under WinXP.
</li>
<li><code>configs/z80sim</code>:
z80 Microcontroller. This port uses a Z80 instruction set simulator.
That simulator can be found in the NuttX CVS
<a href="http://nuttx.cvs.sourceforge.net/nuttx/misc/sims/z80sim/">here</a>.
This port also the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain
under Linux or Cygwin(verfied with version 2.6.0).
</li>
<li><code>configs/z8encore000zco</code>
z8Encore! Microcontroller. This port use the Zilog z8encore000zco
development kit, Z8F6403 part, and the Zilog ZDS-II Windows command line
tools. The development environment is Cygwin under WinXP.
</li>
<li><code>configs/z8encore000zco</code>
z8Encore! Microcontroller. This port use the Zilog z8f64200100kit
development kit, Z8F6423 part, and the Zilog ZDS-II Windows command line
tools. The development environment is Cygwin under WinXP.
</li>
</ul>
<p><small><blockquote>
* A customized version of the <a href="http://www.buildroot.org">buildroot</a>
is available to build these toolchains under Linux or Cygwin.
</blockquote></small></p>
<h2>2.4 <a name="DirStructDrivers">drivers</a></h2>
<p>
This directory holds architecture-independent device drivers.
</p>
<ul><pre>
drivers/
|-- Makefile
|-- bch/
| |-- Make.defs
| `-- <i>(bch driver source files)</i>
|-- mmcsd/
| |-- Make.defs
| `-- <i>(mmcsd driver source files)</i>
|-- net/
| |-- Make.defs
| `-- <i>(net driver source files)</i>
|-- usbdev/
| |-- Make.defs
| `-- <i>(usbdev driver source files)</i>
`-- <i>(common driver source files)</i>
</pre></ul>
<h2>2.5 <a name="DirStructExamples">examples</a></h2>
<p>
Example and test programs to build against.
</p>
<h2>2.6 <a name="DirStructFs">fs</a></h2>
<p>
This directory contains the NuttX file system.
This file system is described <a href="#NxFileSystem">below</a>.
</p>
<ul><pre>
fs/
|-- Makefile
|-- fat/
| |-- Make.defs
| `-- <i>(fat file system source files)</i>
|-- romfs/
| |-- Make.defs
| `-- <i>(romfs file system source files)</i>
`-- <i>(common file system source files)</i>
</pre></ul>
<h2>2.7 <a name="DirStructGraphics">graphics</a></h2>
<p>
This directory contains files for graphics/video support under NuttX.
</p>
<ul><pre>
graphics/
|-- Makefile
|-- nxglib/
| |-- Make.defs
| `-- <i>(NuttX graphics library source files)</i>
|-- nx/
| |-- Make.defs
| `-- <i>(Nuttx X-server source files)</i>
`-- <i>(common file system source files)</i>
</pre></ul>
<h2>2.8 <a name="DirStructInclude">include</a></h2>
<p>
This directory holds NuttX header files.
Standard header files file retained in can be included in the <i>normal</i> fashion:
</p>
<ul>
<code>include <stdio.h></code><br>
<code>include <sys/types.h></code><br>
etc.
</ul>
<p>
Directory structure:
</p>
<ul><pre>
include/
|-- <i>(standard header files)</i>
|-- arpa/
| `-- <i>(standard header files)</i>
|-- net/
| `-- uip/
| `-- <i>(uIP specific header files)</i>
|-- netinet/
| `-- <i>(standard header files)</i>
|-- nuttx/
| `-- <i>(nuttx specific header files)</i>
`- sys/
`-- <i>(more standard header files)</i>
</per></ul>
<h2>2.9 <a name="DirStructLib">lib</a></h2>
<p>
This directory holds a collection of standard libc-like functions with custom
interfaces into Nuttx.
</p>
<h2>2.10 <a name="DirStructMm">mm</a></h2>
<p>
This is the NuttX memory manager.
</p>
<h2>2.11 <a name="DirStructNet">net</a></h2>
<p>
This directory contains the implementation of the socket APIs.
The subdirectory, <code>uip</code> contians the uIP port.
</P>
<h2>2.12 <a name="DirStructNetUtils">netutils</a></h2>
<p>
This directory contains most of the network applications.
Some of these are original with NuttX (like tftpc and dhcpd) and others were leveraged from the uIP-1.0 apps directory.
As the uIP apps/README says, these applications "are not all heavily tested."
</p>
<ul><pre>
netutils/
|-- Makefile
|-- dhcp/
| |-- Make.defs
| `-- <i>(dhcp source files)</i>
|-- dhcpd/
| |-- Make.defs
| `-- <i>(dhcpd source files)</i>
|-- resolv/
| |-- Make.defs
| `-- <i>(resolv source files)</i>
|-- smtp/
| |-- Make.defs
| `-- <i>(smtp source files)</i>
|-- telnetd/
| |-- Make.defs
| `-- <i>(telnetd source files)</i>
|-- tftpc/
| |-- Make.defs
| `-- <i>(tftpc source files)</i>
|-- uiplib/
| |-- Make.defs
| `-- <i>(uiplib source files)</i>
|-- weblclient/
| |-- Make.defs
| `-- <i>(webclient source files)</i>
|-- webserver/
| |-- Make.defs
| `-- <i>(webserver source files)</i>
`-- <i>(netutils common files)</i>
</pre></ul>
<h2>2.13 <a name="DirStructSched">sched</a></h2>
<p>
The files forming core of the NuttX RTOS reside here.
</p>
<h2>2.14 <a name="DirStructTools">tools</a></h2>
<p>
This directory holds a collection of tools and scripts to simplify
configuring, building and maintaining NuttX.
</p>
<ul><pre>
tools/
|-- Makefile.mkconfig
|-- configure.sh
|-- incdir.sh
|-- indent.sh
|-- link.sh
|-- mkconfig.c
|-- mkdeps.sh
|-- mkimage.sh
|-- mknulldeps.sh
|-- unlink.sh
|-- winlink.sh
`-- zipme
</pre></ul>
<h2>2.15 <a name="topmakefile">Makefile</a></h2>
<p>
The top-level <code>Makefile</code> in the <code>${TOPDIR}</code> directory contains all of the top-level control
logic to build NuttX.
Use of this <code>Makefile</code> to build NuttX is described <a href="#buildingnuttx">below</a>.
</p>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1>3.0 <a name="configandbuild">Configuring and Building</a></h1>
</td>
</tr>
</table>
<h2><a name="configuringnuttx">3.1 Configuring NuttX</a></h2>
<p>
<b>Manual Configuration</b>.
Configuring NuttX requires only copying the
<a href="#boardconfigsubdirs">board-specific configuration files</a> into the top level directory which appears in the make files as the make variable, <code>${TOPDIR}</code>.
This could be done manually as follows:
</p>
<ul>
<li>Copy <code>configs/</code><i><board-name></i><code>/[</code><i><config-dir></i><code>/]Make.def</code> to <code>${TOPDIR}/Make.defs</code>,<li>
<li>Copy <code>configs/</code><i><board-name></i><code>/[</code><i><config-dir></i><code>/]setenv.sh</code> to <code>${TOPDIR}/setenv.sh</code>, and</li>
<li>Copy <code>configs/</code><i><board-name></i><code>/[</code><i><config-dir></i><code>/]defconfig</code> to <code>${TOPDIR}/.config</code></li>
</ul>
<p>
Where <i><board-name></i> is the name of one of the sub-directories of the
NuttX <a href="#DirStructConfigs"><code>configs/</code></a> directory.
This sub-directory name corresponds to one of the supported boards
identified <a href="#supportedboards">above</a>.
And <config-dir> is the optional, specific configuration directory for the board.
</p>
<p>
<b>Automated Configuration</b>.
There is a script that automates these steps. The following steps will
accomplish the same configuration:
</p>
<ul><pre>
cd tools
./configure.sh <i><board-name></i></i><code>[/</code><i><config-dir></i><code>]</code>
</pre></ul>
<p>
<b>Additional Configuration Steps</b>.
The remainder of configuration steps will be performed by <a href="#topmakefile"><code>${TOPDIR}/Makefile</code></a>
the first time the system is built as described below.
</p>
<h2><a name="buildingnuttx">3.2 Building NuttX</a></h2>
<p>
<b>Building NuttX</b>.
Once NuttX has been configured as described <a href="#configuringnuttx">above</a>, it may be built as follows:
</p>
<ul><pre>
cd ${TOPDIR}
source ./setenv.sh
make
</pre></ul>
<p>
The <code>${TOPDIR}</code> directory holds:
</p>
<ul>
<li>The top level <a href="#topmakefile"><code>Makefile</code></a> that controls the NuttX build.
</ul>
<p>
That directory also holds:
</p>
<ul>
<li>The makefile fragment <a href="#boardconfigsubdirs"><code>.config</code></a> that describes the current configuration.</li>
<li>The makefile fragment <a href="#boardconfigsubdirs"><code>Make.defs</code></a> that provides customized build targers, and</li>
<li>The shell script <a href="#boardconfigsubdirs"><code>setenv.sh</code></a> that sets up the configuration environment for the build.</li>
</ul>
<p>
The <a href="#boardconfigsubdirs"><code>setenv.sh</code></a> contains Linux/Cygwin environmental settings that are needed for the build.
The specific environmental definitions are unique for each board but should include, as a minimum, updates to the <code>PATH</code> variable to include the full path to the architecture-specific toolchain identified in <a href="#boardconfigsubdirs"><code>Make.defs</code></a>.
The <a href="#boardconfigsubdirs"><code>setenv.sh</code></a> only needs to be source'ed at the beginning of a session.
The system can be re-made subsequently by just typing <code>make</code>.
</p>
<p>
<b>First Time Make.</b>
Additional configuration actions will be taken the first time that system is built.
These additional steps include:
</p>
<ul>
<li>Auto-generating the file <code>include/nuttx/config.</code> using the <code>${TOPDIR}/.config</code> file.
<li>Creating a link to <code>${TOPDIR}/arch/</code><i><arch-name></i><code>/include</code> at <code>${TOPDIR}/include/arch</code>.
<li>Creating a link to <code>${TOPDIR}/configs/</code><i><board-name></i><code>/include</code> at <code>${TOPDIR}/include/arch/board</code>.
<li>Creating a link to <code>${TOPDIR}/configs/</code><i><board-name></i><code>/src</code> at <code>${TOPDIR}/arch/</code><i><arch-name></i><code>/src/board</code>
<li>Creating make dependencies.
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1>4.0 <a name="ArchAPIs">Architecture APIs</a></h1>
</td>
</tr>
</table>
<p>
The file <code>include/nuttx/arch.h</code> identifies by prototype all of the APIs that must
be provided by the architecture specific logic.
The internal OS APIs that architecture-specific logic must
interface with also also identified in <code>include/nuttx/arch.h</code> or in
other header files.
</p>
<h2><a name="imports">4.1 APIs Exported by Architecture-Specific Logic to NuttX</a></h2>
<h3><a name="upinitialize">4.1.1 <code>up_initialize()</code></a></h3>
<p><b>Prototype</b>: <code>void up_initialize(void);</code></p>
<p><b>Description</b>.
<code>up_initialize()</code> will be called once during OS
initialization after the basic OS services have been
initialized. The architecture specific details of
initializing the OS will be handled here. Such things as
setting up interrupt service routines, starting the
clock, and registering <a href="#DeviceDrivers">device drivers</a> are some of the
things that are different for each processor and hardware
platform.
</p>
<p>
<code>up_initialize()</code> is called after the OS initialized but
before the init process has been started and before the
libraries have been initialized. OS services and driver
services are available.
</p>
<h3><a name="upidle">4.1.2 <code>up_idle()</code></a></h3>
<p><b>Prototype</b>: <code>void up_idle(void);</code></p>
<p><b>Description</b>.
<code>up_idle()</code> is the logic that will be executed
when their is no other ready-to-run task. This is processor
idle time and will continue until some interrupt occurs to
cause a context switch from the idle task.
</p>
<p>
Processing in this state may be processor-specific. e.g.,
this is where power management operations might be performed.
</p>
<h3><a name="upinitialstate">4.1.3 <code>up_initial_state()</code></a></h3>
<p><b>Prototype</b>: <code>void up_initial_state(FAR _TCB *tcb);</code></p>
<p><b>Description</b>.
A new thread is being started and a new TCB
has been created. This function is called to initialize
the processor specific portions of the new TCB.
</p>
<p>
This function must setup the intial architecture registers
and/or stack so that execution will begin at tcb->start
on the next context switch.
</p>
<h3><a name="upcreatestack">4.1.4 <code>up_create_stack()</code></a></h3>
<p><b>Prototype</b>: <code>STATUS up_create_stack(FAR _TCB *tcb, size_t stack_size);</code></p>
<p><b>Description</b>.
Allocate a stack for a new thread and setup
up stack-related information in the TCB.
</p>
<p>
The following TCB fields must be initialized:
</p>
<ul>
<li><code>adj_stack_size</code>: Stack size after adjustment for hardware,
processor, etc. This value is retained only for debug
purposes.</li>
<li><code>stack_alloc_ptr</code>: Pointer to allocated stack</li>
<li><code>adj_stack_ptr</code>: Adjusted <code>stack_alloc_ptr</code> for HW. The
initial value of the stack pointer.
</ul>
<p>
This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code>
is defined.
</p>
<p><b>Inputs</b>:</p?
<ul>
<li>
<code>tcb</code>: The TCB of new task.
</li>
<li>
<code>stack_size</code>: The requested stack size. At least this much
must be allocated.
</li>
</ul>
<h3><a name="upusestack">4.1.5 <code>up_use_stack()</code></a></h3>
<p><b>Prototype</b>:
<code>STATUS up_use_stack(FAR _TCB *tcb, FAR void *stack, size_t stack_size);</code>
</p>
<p><b>Description</b>.
Setup up stack-related information in the TCB
using pre-allocated stack memory.
</p>
<p>
The following TCB fields must be initialized:
</p>
<ul>
<li><code>adj_stack_size</code>: Stack size after adjustment for hardware,
processor, etc. This value is retained only for debug
purposes.</li>
<li><code>stack_alloc_ptr</code>: Pointer to allocated stack</li>
<li><code>adj_stack_ptr</code>: Adjusted <code>stack_alloc_ptr</code> for HW. The
initial value of the stack pointer.
</ul>
<p>
This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code>
is defined.
</p>
<p><b>Inputs:</b></p>
<ul>
<li>
<code>tcb</code>: The TCB of new task.
</li>
<li>
<code>stack_size</code>: The allocated stack size.
</li>
</ul>
<h3><a name="upreleasestack">4.1.6 <code>up_release_stack()</code></a></h3>
<p><b>Prototype</b>: <code>void up_release_stack(FAR _TCB *dtcb);</code></p>
<p><b>Description</b>.
A task has been stopped. Free all stack
related resources retained int the defunct TCB.
</p>
<p>
This API is <i>NOT</i> required if <code>CONFIG_CUSTOM_STACK</code>
is defined.
</p>
<h3><a name="upunblocktask">4.1.7 <code>up_unblock_task()</code></a></h3>
<p><b>Prototype</b>: <code>void up_unblock_task(FAR _TCB *tcb);</code></p>
<p><b>Description</b>.
A task is currently in an inactive task list
but has been prepped to execute. Move the TCB to the
ready-to-run list, restore its context, and start execution.
</p>
<p>
This function is called only from the NuttX scheduling
logic. Interrupts will always be disabled when this
function is called.
</p>
<p><b>Inputs</b>:
<ul>
<li><code>tcb</code>: Refers to the tcb to be unblocked. This tcb is
in one of the waiting tasks lists. It must be moved to
the ready-to-run list and, if it is the highest priority
ready to run taks, executed.
</li>
</ul>
<h3><a name="upblocktask">4.1.8 <code>up_block_task()</code></a></h3>
<p><b>Prototype</b>: <code>void up_block_task(FAR _TCB *tcb, tstate_t task_state);</code></p>
<p><b>Description</b>.
The currently executing task at the head of
the ready to run list must be stopped. Save its context
and move it to the inactive list specified by task_state.
This function is called only from the NuttX scheduling
logic. Interrupts will always be disabled when this
function is called.
<p><b>Inputs:</b></p>
<ul>
<li><code>tcb</code>: Refers to a task in the ready-to-run list (normally
the task at the head of the list). It most be
stopped, its context saved and moved into one of the
waiting task lists. It it was the task at the head
of the ready-to-run list, then a context to the new
ready to run task must be performed.
</li>
<li><code>task_state</code>: Specifies which waiting task list should be
hold the blocked task TCB.
</li>
</ul>
<h3><a name="upreleasepending">4.1.9 <code>up_release_pending()</code></a></h3>
<p><b>Prototype</b>: <code>void up_release_pending(void);</code></p>
<p><b>Description</b>.
When tasks become ready-to-run but cannot run because pre-emption
is disabled, they are placed into a pending task list.
This function releases and makes ready-to-run all of the tasks that have
collected in the pending task list. This can cause a
context switch if a new task is placed at the head of
the ready to run list.
</p>
<p>
This function is called only from the NuttX scheduling logic when
pre-emption is re-enabled. Interrupts will always be disabled when this
function is called.
</p>
<h3><a name="upreprioritizertr">4.1.10 <code>up_reprioritize_rtr()</code></a></h3>
<p><b>Prototype</b>: <code>void up_reprioritize_rtr(FAR _TCB *tcb, ubyte priority);</code></p>
<p><b>Description</b>.
Called when the priority of a running or
ready-to-run task changes and the reprioritization will
cause a context switch. Two cases:
</p>
<ol>
<li>
The priority of the currently running task drops and the next
task in the ready to run list has priority.
</li>
<li>
An idle, ready to run task's priority has been raised above the
the priority of the current, running task and it now has the
priority.
</li>
</ol>
<p>
This function is called only from the NuttX scheduling
logic. Interrupts will always be disabled when this
function is called.
</p>
<p><b>Inputs:</b></p>
<ul>
<li>
<code>tcb</code>: The TCB of the task that has been reprioritized
</li>
<li>
<code>priority</code>: The new task priority
</li>
</ul>
<h3><a name="_exit">4.1.11 <code>_exit()</code></a></h3>
<p><b>Prototype</b>: <code>void _exit(int status) noreturn_function;</code></p>
<p><b>Description</b>.
This function causes the currently executing task to cease
to exist. This is a special case of task_delete().
</p>
<p>
Unlike other UP APIs, this function may be called
directly from user programs in various states. The
implementation of this function should diable interrupts
before performing scheduling operations.
</p>
<h3><a name="upassert">4.1.12 <code>up_assert()</code></a></h3>
<p><b>Prototype</b>:<br>
<code>void up_assert(FAR const ubyte *filename, int linenum);</code></br>
<code>void up_assert_code(FAR const ubyte *filename, int linenum, int error_code);</code></br>
</p>
<p><b>Description</b>.
Assertions may be handled in an architecture-specific
way.
</p>
<h3><a name="upschedulesigaction">4.1.13 <code>up_schedule_sigaction()</code></a></h3>
<p><b>Prototype</b>:
<code>void up_schedule_sigaction(FAR _TCB *tcb, sig_deliver_t sigdeliver);</code>
</p>
<p><b>Description</b>.
This function is called by the OS when one or more
signal handling actions have been queued for execution.
The architecture specific code must configure things so
that the 'igdeliver' callback is executed on the thread
specified by 'tcb' as soon as possible.
</p>
<p>
This function may be called from interrupt handling logic.
</p>
<p>
This operation should not cause the task to be unblocked
nor should it cause any immediate execution of sigdeliver.
Typically, a few cases need to be considered:
</p>
<ol>
<li>
This function may be called from an interrupt handler
During interrupt processing, all xcptcontext structures
should be valid for all tasks. That structure should
be modified to invoke sigdeliver() either on return
from (this) interrupt or on some subsequent context
switch to the recipient task.
</li>
<li>
If not in an interrupt handler and the tcb is NOT
the currently executing task, then again just modify
the saved xcptcontext structure for the recipient
task so it will invoke sigdeliver when that task is
later resumed.
</li>
<li>
If not in an interrupt handler and the tcb IS the
currently executing task -- just call the signal
handler now.
</li>
</ol>
<p>
This API is <i>NOT</i> required if <code>CONFIG_DISABLE_SIGNALS</code>
is defined.
</p>
<h3><a name="upallocateheap">4.1.14 <code>up_allocate_heap()</code></a></h3>
<p><b>Prototype</b>: <code>void up_allocate_heap(FAR void **heap_start, size_t *heap_size);</code></p>
<p><b>Description</b>.
The heap may be statically allocated by
defining CONFIG_HEAP_BASE and CONFIG_HEAP_SIZE. If these
are not defined, then this function will be called to
dynamically set aside the heap region.
</p>
<p>
This API is <i>NOT</i> required if <code>CONFIG_HEAP_BASE</code>
is defined.
</p>
<h3><a name="upinterruptcontext">4.1.15 <code>up_interrupt_context()</code></a></h3>
<p><b>Prototype</b>: <code>boolean up_interrupt_context(void)</code></p>
<p><b>Description</b>.
Return TRUE is we are currently executing in
the interrupt handler context.
</p>
<h3><a name="updisableirq">4.1.16 <code>up_disable_irq()</code></a></h3>
<p><b>Prototype</b>:</p>
<ul><pre>
#ifndef CONFIG_ARCH_NOINTC
void up_disable_irq(int irq);
#endf
</pre></ul>
<p><b>Description</b>.
Disable the IRQ specified by 'irq'
On many architectures, there are three levels of interrupt enabling: (1)
at the global level, (2) at the level of the interrupt controller,
and (3) at the device level. In order to receive interrupts, they
must be enabled at all three levels.
</p>
<p>
This function implements enabling of the device specified by 'irq'
at the interrupt controller level if supported by the architecture
(irqsave() supports the global level, the device level is hardware
specific).
<p>
If the architecture does not support <code>up_disable_irq</code>,
<code>CONFIG_ARCH_NOINTC</code> should be defined in the NuttX configuration file.
Since this API cannot be supported on all architectures, it should be
avoided in common implementations where possible.
</p>
<h3><a name="upenableirq">4.1.17 <code>up_enable_irq()</code></a></h3>
<p><b>Prototype</b>:</p>
<ul><pre>
#ifndef CONFIG_ARCH_NOINTC
void up_enable_irq(int irq);
#endf
</pre></ul>
<p><b>Description</b>.
This function implements disabling of the device specified by 'irq'
at the interrupt controller level if supported by the architecture
(irqrestore() supports the global level, the device level is hardware
specific).
</p>
<p>
If the architecture does not support <code>up_disable_irq</code>,
<code>CONFIG_ARCH_NOINTC</code> should be defined in the NuttX configuration file.
Since this API cannot be supported on all architectures, it should be
avoided in common implementations where possible.
</p>
<h3><a name="upprioritizeirq">4.1.18 <code>up_prioritize_irq()</code></a></h3>
<p><b>Prototype</b>:</p>
<ul><pre>
#ifdef CONFIG_ARCH_IRQPRIO
void up_enable_irq(int irq);
#endf
</pre></ul>
<p><b>Description</b>.
Set the priority of an IRQ.
</p>
<p>
If the architecture supports <code>up_enable_irq</code>,
<code>CONFIG_ARCH_IRQPRIO</code> should be defined in the NuttX configuration file.
Since this API cannot be supported on all architectures, it should be
avoided in common implementations where possible.
</p>
<h3><a name="upputc">4.1.19 <code>up_putc()</code></a></h3>
<p><b>Prototype</b>: <code>int up_putc(int ch);</code></p>
<p><b>Description</b>.
This is a debug interface exported by the architecture-specific logic.
Output one character on the console
</p>
<h2><a name="exports">4.2 APIs Exported by NuttX to Architecture-Specific Logic</a></h2>
<p>
These are standard interfaces that are exported by the OS
for use by the architecture specific logic.
</p>
<h3><a name="osstart">4.2.1 <code>os_start()</code></a></h3>
<p>
<b><i>To be provided</i></b>
</p>
<h3><a name="listmgmt">4.2.2 OS List Management APIs</a></h3></h3>
<p>
<b><i>To be provided</i></b>
</p>
<h3><a name="schedprocesstimer">4.2.3 <code>sched_process_timer()</code></a></h3>
<p><b>Prototype</b>: <code>void sched_process_timer(void);</code></p>
<p><b>Description</b>.
This function handles system timer events.
The timer interrupt logic itself is implemented in the
architecture specific code, but must call the following OS
function periodically -- the calling interval must be
<code>MSEC_PER_TICK</code>.
</p>
<h3><a name="irqdispatch">4.2.4 <code>irq_dispatch()</code></a></h3>
<p><b>Prototype</b>: <code>void irq_dispatch(int irq, FAR void *context);</code></p>
<p><b>Description</b>.
This function must be called from the achitecture-
specific logic in order to dispaly an interrupt to
the appropriate, registered handling logic.
</p>
<h2><a name="ledsupport">4.3 LED Support</a></h2>
<p>
A board architecture may or may not have LEDs.
If the board does have LEDs, then most architectures provide similar LED support that is enabled when <code>CONFIG_ARCH_LEDS</code>
is selected in the NuttX configuration file.
This LED support is part of architecture-specific logic and is not managed by the core NuttX logic.
However, the support provided by each architecture is sufficiently similar that it can be documented here.
</p>
<h3><a name="ledheaders">4.3.1 Header Files</a></h3>
<p>
LED-related definitions are provided in two header files:
<ul>
<li>
LED definitions are provided for each board in the <code>board.h</code> that resides
in the <code><i><board-name></i>/include/board.h</code> file (which is also
linked to <code>include/arch/board/board.h</code> when the RTOS is configured).
Those definitions are discussed <a href="#leddefinitions">below</a>.
</li>
<li>
The board-specific logic provides unique instances of the LED interfaces.
This is because the implementation of LED support may be very different
on different boards.
Prototypes for these board-specific implementations are, however, provided
in architecture-common header files.
That header file is usually at <code><i><arch-name></i>/src/common/up_internal.h</code>,
but could be at other locations in particular architectures.
These prototypes are discussed <a href="#ledapis">below</a>.
</li>
</ul>
</p>
<h3><a name="leddefinitions">4.3.2 LED Definitions</a></h3>
<p>
The implementation of LED support is very specific to a board architecture.
Some boards have several LEDS, others have only one or two.
Some have none.
Others LED matrices and show alphnumeric data, etc.
The NuttX logic does not refer to specific LEDS, rather, it refers to an event to be shown on the LEDS
in whatever manner is appropriate for the board;
the way that this event is presented depends upon the hardware available on the board.
</p>
<p>
The model used by NuttX is that the board can show 8 events defined as follows in <code><i><board-name></i>/include/board.h</code>:
</p>
<ul><pre>
#define LED_STARTED ??
#define LED_HEAPALLOCATE ??
#define LED_IRQSENABLED ??
#define LED_STACKCREATED ??
#define LED_INIRQ ??
#define LED_SIGNAL ??
#define LED_ASSERTION ??
#define LED_PANIC ??
</pre></ul>
<p>
The specific value assigned to each pre-processor variable can be whatever makes the implementation easiest for the board logic.
The <i>meaning</i> associated with each definition is as follows:
</p>
<ul>
<li>
<code>LED_STARTED</code> is the value that describes the setting of the LEDs when the LED logic is first initialized.
This LED value is set but never cleared.
</li>
<li>
<code>LED_HEAPALLOCATE</code> indicates that the NuttX heap has been configured.
This is an important place in the boot sequence because if the memory is configured wrong, it will probably crash leaving this LED setting.
This LED value is set but never cleared.
</li>
<li>
<code>LED_IRQSENABLED</code> indicates that interrupts have been enabled.
Again, during bring-up (or if there are hardware problems), it is very likely that the system may crash just when interrupts are enabled, leaving this setting on the LEDs.
This LED value is set but never cleared.
</li>
<li>
<code>LED_STACKCREATED</code> is set each time a new stack is created.
If set, it means that the system attempted to start at least one new thread.
This LED value is set but never cleared.
</li>
<li>
<code>LED_INIRQ</code> is set and cleared on entry and exit from each interrupt.
If interrupts are working okay, this LED will have a dull glow.
</li>
<li>
<code>LED_SIGNAL</code> is set and cleared on entry and exit from a signal handler.
Signal handlers are tricky so this is especially useful during bring-up or a new architecture.
</li>
<li>
<code>LED_ASSERTION</code> is set if an assertion occurs.
</li>
<li>
<code>LED_PANIC</code> will blink at around 1Hz if the system panics and hangs.
</li>
</ul>
<h3><a name="ledapis">4.3.3 Common LED interfaces</a></h3>
<p>
The <code><i><arch-name></i>/src/common/up_internal.h</code> probably has definitions
like:
</p>
<ul><pre>
/* Defined in board/up_leds.c */
#ifdef CONFIG_ARCH_LEDS
extern void up_ledinit(void);
extern void up_ledon(int led);
extern void up_ledoff(int led);
#else
# define up_ledinit()
# define up_ledon(led)
# define up_ledoff(led)
#endif
</pre></ul>
<p>
Where:
<p>
<ul>
<li>
<code>void up_ledinit(void)</code> is called early in power-up initialization to initialize the LED hardware.
</li>
<li>
<code>up_ledon(int led)</code> is called to instantiate the LED presentation of the event.
The <code>led</code> argument is one of the definitions provided in <code><i><board-name></i>/include/board.h</code>.
</li>
<li>
<code>up_ledoff(int led</code>is called to terminate the LED presentation of the event.
The <code>led</code> argument is one of the definitions provided in <code><i><board-name></i>/include/board.h</code>.
Note that only <code>LED_INIRQ</code>, <code>LED_SIGNAL</code>, <code>LED_ASSERTION</code>, and <code>LED_PANIC</code>
indications are terminated.
</li>
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1><a name="NxFileSystem">5.0 NuttX File System</a></h1>
</td>
</tr>
</table>
<p><b>Overview</b>.
NuttX includes an optional, scalable file system.
This file-system may be omitted altogther; NuttX does not depend on the presence
of any file system.
</p>
<p><b>Pseudo Root File System</b>.
Or, a simple <i>in-memory</i>, <i>psuedo</i> file system can be enabled.
This simple file system can be enabled setting the CONFIG_NFILE_DESCRIPTORS
option to a non-zero value (see <a href="#apndxconfigs">Appendix A</a>).
This is an <i>in-memory</i> file system because it does not require any
storage medium or block driver support.
Rather, file system contents are generated on-the-fly as referenced via
standard file system operations (open, close, read, write, etc.).
In this sense, the file system is <i>psuedo</i> file system (in the
same sense that the Linux <code>/proc</code> file system is also
referred to as a psuedo file system).
</p>
<p>
Any user supplied data or logic can be accessed via the psuedo-file system.
Built in support is provided for character and block <a href="#DeviceDrivers">drivers</a> in the
<code>/dev</code> psuedo file system directory.
</p>
<p><b>Mounted File Systems</b>
The simple in-memory file system can be extended my mounting block
devices that provide access to true file systems backed up via some
mass storage device.
NuttX supports the standard <code>mount()</code> command that allows
a block driver to be bound to a mountpoint within the psuedo file system
and to a file system.
At present, NuttX supports only the VFAT file system.
</p>
<p><b>Comparison to Linux</b>
From a programming perspective, the NuttX file system appears very similar
to a Linux file system.
However, there is a fundamental difference:
The NuttX root file system is a psuedo file system and true file systems may be
mounted in the psuedo file system.
In the typical Linux installation by comparison, the Linux root file system
is a true file system and psuedo file systems may be mounted in the true,
root file system.
The approach selected by NuttX is intended to support greater scalability
from the very tiny platform to the moderate platform.
</p>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1><a name="DeviceDrivers">6.0 NuttX Device Drivers</a></h1>
</td>
</tr>
</table>
<p>
NuttX supports a variety of device drivers including:
<ul>
<li><i>Character</i> Device Drivers,</li>
<li><i>Block</i> Device Drivers, and</li>
<li>Other <i>Specialized</i> Drivers.</li>
</ul>
These different device driver types are discussed in the following paragraphs.
Note: device driver support requires that the <i>in-memory</i>, <i>psuedo</i> file system
is enabled by setting the CONFIG_NFILE_DESCRIPTORS in the NuttX configuration file to a
non-zero value.
</p>
<h2><a name="chardrivers">6.1 Character Device Drivers</a></h2>
<p>
Character device drivers have these properties:
</p>
<ul>
<li>
<b><code>include/nuttx/fs.h</code></b>.
All structures and APIs needed to work with character drivers are provided in this header file.
</li>
<li>
<b><code>struct file_operations</code></b>.
Each character device driver must implement an instance of <code>struct file_operations</code>.
That structure defines a call table with the following methods:
<ul>
<p><code>int open(FAR struct file *filp);</code><br>
<code>int close(FAR struct file *filp);</code><br>
<code>ssize_t read(FAR struct file *filp, FAR char *buffer, size_t buflen);</code><br>
<code>ssize_t write(FAR struct file *filp, FAR const char *buffer, size_t buflen);</code><br>
<code>off_t seek(FAR struct file *filp, off_t offset, int whence);</code><br>
<code>int ioctl(FAR struct file *filp, int cmd, unsigned long arg);</code><br>
<code>int poll(FAR struct file *filp, struct pollfd *fds, boolean setup);</code></p>
</ul>
</li>
<li>
<b><code>int register_driver(const char *path, const struct file_operations *fops, mode_t mode, void *priv);</code></b>.
Each character driver registers itself by calling <code>register_driver()</code>, passing it the
<code>path</code> where it will appear in the <a href="#NxFileSystem">pseudo-file-system</a> and it's
initialized instance of <code>struct file_operations</code>.
</li>
<li>
<b>User Access</b>.
After it has been registered, the character driver can be accessed by user code using the standard
<a href="NuttxUserGuide.html#driveroperations">driver operations</a> including
<code>open()</code>, <code>close()</code>, <code>read()</code>, <code>write()</code>, etc.
</li>
<li>
<b>Examples</b>:
<code>drivers/dev_null.c</code>, <code>drivers/fifo.c</code>, <code>drivers/serial.c</code>, etc.
</li>
</ul>
<h2><a name="blockdrivers">6.2 Block Device Drivers</a></h2>
<p>
Block device drivers have these properties:
</p>
<ul>
<li>
<b><code>include/nuttx/fs.h</code></b>.
All structures and APIs needed to work with block drivers are provided in this header file.
</li>
<li>
<b><code>struct block_operations</code></b>.
Each block device driver must implement an instance of <code>struct block_operations</code>.
That structure defines a call table with the following methods:
<ul>
<p><code>int open(FAR struct inode *inode);</code><br>
<code>int close(FAR struct inode *inode);</code><br>
<code>ssize_t read(FAR struct inode *inode, FAR unsigned char *buffer, size_t start_sector, unsigned int nsectors);</code><br>
<code>ssize_t write(FAR struct inode *inode, FAR const unsigned char *buffer, size_t start_sector, unsigned int nsectors);</code><br>
<code>int geometry(FAR struct inode *inode, FAR struct geometry *geometry);</code><br>
<code>int ioctl(FAR struct inode *inode, int cmd, unsigned long arg);</code></p>
</ul>
</li>
<li>
<b><code>int register_blockdriver(const char *path, const struct block_operations *bops, mode_t mode, void *priv);</code></b>.
Each block driver registers itself by calling <code>register_blockdriver()</code>, passing it the
<code>path</code> where it will appear in the <a href="#NxFileSystem">pseudo-file-system</a> and it's
initialized instance of <code>struct block_operations</code>.
</li>
<li>
<b>User Access</b>.
Users do not normally access block drivers directly, rather, they access block drivers
indirectly through the <code>mount()</code> API.
The <code>mount()</code> API binds a block driver instance with a file system and with a mountpoint.
Then the user may use the block driver to access the file system on the underlying media.
<i>Example</i>: See the <code>cmd_mount()</code> implementation in <code>examples/nsh/nsh_fscmds.c</code>.
</li>
<li>
<b>Accessing a Character Driver as a Block Device</b>.
See the loop device at <code>drivers/loop.c</code>.
<i>Example</i>: See the <code>cmd_losetup()</code> implementation in <code>examples/nsh/nsh_fscmds.c</code>.
</li>
<li>
<b>Accessing a Block Driver as Character Device</b>.
See the Block-to-Character (BCH) conversion logic in <code>drivers/bch/</code>.
<i>Example</i>: See the <code>cmd_dd()</code> implementation in <code>examples/nsh/nsh_ddcmd.c</code>.
</li>
<li>
<b>Examples</b>.
<code>drivers/loop.c</code>, <code>drivers/mmcds/mmcsd_spi.c</code>, <code>drivers/ramdisk.c</code>, etc.
</li>
</ul>
<h2><a name="blockdrivers">6.3 Specialized Device Drivers</a></h2>
<h3><a name="ethdrivers">6.3.1 Ethernet Device Drivers</a></h3>
<ul>
<li>
<b><code>include/net/uip/uip-arch.h</code></b>.
All structures and APIs needed to work with Ethernet drivers are provided in this header file.
The structure <code>struct uip_driver_s</code> defines the interface and is passed to uIP via
<code>netdev_register()</code>.
</li>
<li>
<b><code>int netdev_register(FAR struct uip_driver_s *dev);</code></b>.
Each Eterhenet driver registers itself by calling <code>netdev_register()</code>.
</li>
<li>
<b>Examples</b>:
<code>drivers/net/dm90x0.c</code>, <code>arch/drivers/arm/src/c5471/c5471_ethernet.c</code>, <code>arch/z80/src/ez80/ez80_emac.c</code>, etc.
</li>
</ul>
<h3><a name="spidrivers">6.3.2 SPI Device Drivers</a></h3>
<ul>
<li>
<b><code>include/nuttx/spi.h</code></b>.
All structures and APIs needed to work with SPI drivers are provided in this header file.
</li>
<li>
<b><code>struct spi_ops_s</code></b>.
Each SPI device driver must implement an instance of <code>struct spi_ops_s</code>.
That structure defines a call table with the following methods:
<ul>
<p><code>void select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, boolean selected);</code><br>
<code>uint32 setfrequency(FAR struct spi_dev_s *dev, uint32 frequency);</code><br>
<code>void setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);</code><br>
<code>void setbits(FAR struct spi_dev_s *dev, int nbits);</code><br>
<code>ubyte status(FAR struct spi_dev_s *dev, enum spi_dev_e devid);</code><br>
<code>uint16 send(FAR struct spi_dev_s *dev, uint16 wd);</code><br>
<code>void exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer, FAR void *rxbuffer, size_t nwords);</code><br>
<p><codei>nt registercallback(FAR struct spi_dev_s *dev, mediachange_t callback, void *arg);</code></p>
</ul>
<li>
<b>Binding SPI Drivers</b>.
SPI drivers are not normally directly accessed by user code, but are usually bound to another,
higher level device driver.
See for example, <code>int mmcsd_spislotinitialize(int minor, int slotno, FAR struct spi_dev_s *spi)</code> in <code>drivers/mmcsd/mmcsd_spi.c</code>.
</li>
<li>
<b>Examples</b>:
<code>drivers/loop.c</code>, <code>drivers/mmcds/mmcsd_spi.c</code>, <code>drivers/ramdisk.c</code>, etc.
</li>
</ul>
<h3><a name="i2cdrivers">6.3.3 I2C Device Drivers</a></h3>
<ul>
<li>
<b><code>include/nuttx/i2c.h</code></b>.
All structures and APIs needed to work with I2C drivers are provided in this header file.
</li>
<li>
<b><code>struct i2c_ops_s</code></b>.
Each I2C device driver must implement an instance of <code>struct i2c_ops_s</code>.
That structure defines a call table with the following methods:
<ul>
<p><code>uint32 setfrequency(FAR struct i2c_dev_s *dev, uint32 frequency);</code><br>
<code>int setaddress(FAR struct i2c_dev_s *dev, int addr, int nbits);</code><br>
<code>int write(FAR struct i2c_dev_s *dev, const ubyte *buffer, int buflen);</code><br>
<code>int read(FAR struct i2c_dev_s *dev, ubyte *buffer, int buflen);</code></p>
</ul>
<li>
<b>Binding I2C Drivers</b>.
SPI drivers are not normally directly accessed by user code, but are usually bound to another,
higher level device driver.
</li>
<li>
<b>Examples</b>:
<code>arch/z80/src/ez80/ez80_i2c.c</code>, <code>arch/z80/src/z8/z8_i2c.c</code>, etc.
</li>
</ul>
<h3><a name="serialdrivers">6.3.4 Serial Device Drivers</a></h3>
<ul>
<li>
<b><code>include/nuttx/serial.h</code></b>.
All structures and APIs needed to work with serial drivers are provided in this header file.
</li>
<li>
<b><code>struct uart_ops_s</code></b>.
Each serial device driver must implement an instance of <code>struct uart_ops_s</code>.
That structure defines a call table with the following methods:
<ul>
<p><code>int setup(FAR struct uart_dev_s *dev);</code><br>
<code>void shutdown(FAR struct uart_dev_s *dev);</code><br>
<code>int attach(FAR struct uart_dev_s *dev);</code><br>
<code>void detach(FAR struct uart_dev_s *dev);</code><br>
<code>int ioctl(FAR struct file *filep, int cmd, unsigned long arg);</code><br>
<code>int receive(FAR struct uart_dev_s *dev, unsigned int *status);</code><br>
<code>void rxint(FAR struct uart_dev_s *dev, boolean enable);</code><br>
<code>boolean rxavailable(FAR struct uart_dev_s *dev);</code><br>
<code>void send(FAR struct uart_dev_s *dev, int ch);</code><br>
<code>void txint(FAR struct uart_dev_s *dev, boolean enable);</code><br>
<code>boolean txready(FAR struct uart_dev_s *dev);</code><br>
<code>boolean txempty(FAR struct uart_dev_s *dev);</code></p>
</ul>
</li>
<li>
<b><code>int uart_register(FAR const char *path, FAR uart_dev_t *dev);</code></b>.
A serial driver may register itself by calling <code>uart_register()</code>, passing it the
<code>path</code> where it will appear in the <a href="#NxFileSystem">pseudo-file-system</a> and it's
initialized instance of <code>struct uart_ops_s</code>.
By convention, serial device drivers are registered at pathes like <code>/dev/ttyS0</code>, <code>/dev/ttyS1</code>, etc.
See the <code>uart_register()</code> implementation in <code>drivers/serial.c</code>.
</li>
<li>
<b>User Access</b>.
Serial drivers are, ultimately, normal <a href="#chardrivers">character drivers</a> and are accessed as other character drivers.
</li>
<li>
<b>Examples</b>:
<code>arch/arm/src/chip/lm3s_serial.c</code>, <code>arch/arm/src/lpc214x/lpc214x_serial.c</code>, <code>arch/z16/src/z16f/z16f_serial.c</code>, etc.
</li>
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1><a name="apndxconfigs">Appendix A: NuttX Configuration Settings</a></h1>
</td>
</tr>
</table>
<p>
The following variables are recognized by the build (you may
also include architecture-specific settings).
</p>
<h2>Architecture selection</h2>
<p>
The following configuration itemes select the architecture, chip, and
board configuration for the build.
</p>
<ul>
<li><code>CONFIG_ARCH</code>:
Identifies the arch subdirectory</li>
<li><code>CONFIG_ARCH_name</code>:
For use in C code</li>
<li><code>CONFIG_ARCH_CHIP</code>:
Identifies the arch/*/chip subdirectory</li>
<li><code>CONFIG_ARCH_CHIP_name</code>:
For use in C code</li>
<li><code>CONFIG_ARCH_BOARD</code>:
Identifies the configs subdirectory and hence, the board that supports
the particular chip or SoC.</li>
<li><code>CONFIG_ARCH_BOARD_name</code>:
For use in C code</li>
<li><code>CONFIG_ENDIAN_BIG</code>:
Define if big endian (default is little endian).</li>
<li><code>CONFIG_ARCH_NOINTC</code>:
Define if the architecture does not support an interrupt controller
or otherwise cannot support APIs like up_enable_irq() and up_disable_irq().</li>
<li><code>CONFIG_ARCH_IRQPRIO</code>:
Define if the architecture suports prioritizaton of interrupts and the
up_prioritize_irq() API.</li>
</ul>
<p>
Some architectures require a description of the RAM configuration:
</p>
<ul>
<li><code>CONFIG_DRAM_SIZE</code>:
Describes the installed DRAM.</li>
<li><code>CONFIG_DRAM_START</code>:
The start address of DRAM (physical)</li>
<li><code>CONFIG_DRAM_VSTART</code>:
The start address of DRAM (virtual)</li>
</ul>
<p>
General build options:
</p>
<ul>
<li><code>CONFIG_RRLOAD_BINARY</code>:
Make the rrload binary format used with BSPs from <a href="www.ridgerun.com">ridgerun.com</a>
using the <code>tools/mkimage.sh</code> script.
</li>
<li><code>CONFIG_INTELHEX_BINARY</code>:
Make the Intel HEX binary format used with many different loaders using the GNU objcopy program
This option hould not be selected if you are not using the GNU toolchain.
</li>
<li><code>CONFIG_MOTOROLA_SREC</code>:
Make the Motorola S-Record binary format used with many different loaders using the GNU objcopy program
Should not be selected if you are not using the GNU toolchain.
</li>
<li><code>CONFIG_RAW_BINARY</code>:
mmke a raw binary format file used with many different loaders using the GNU objcopy program.
This option should not be selected if you are not using the GNU toolchain.
</li>
<li><code>CONFIG_HAVE_LIBM</code>:
Toolchain supports libm.a
</li>
<li><code>CONFIG_HAVE_CXX</code>:
Toolchain supports C++ and <code>CXX</code>, <code>CXXFLAGS</code>, and <code>COMPILEXX</code>
have been defined in the configuratins <code>Make.defs</code> file.
</li>
</ul>
<h2>General OS setup</h2>
<ul>
<li>
<code>CONFIG_EXAMPLE</code>: identifies the subdirectory in examples
that will be used in the build.
</li>
<li>
<code>CONFIG_DEBUG</code>: enables built-in debug options
</li>
<li>
<code>CONFIG_DEBUG_VERBOSE</code>: enables verbose debug output
</li>
<li>
<code>CONFIG_DEBUG_SCHED</code>: enable OS debug output (disabled by default)
</li>
<li>
<code>CONFIG_DEBUG_MM</code>: enable memory management debug output (disabld by default)
</li>
<li>
<code>CONFIG_DEBUG_NET</code>: enable network debug output (disabled by default)
</li>
<li>
<code>CONFIG_DEBUG_FS</code>: enable file system debug output (disabled by default)
</li>
<li>
<code>CONFIG_DEBUG_LIB</code>: enable C library debug output (disabled by default)
</li>
<li>
<code>CONFIG_ARCH_LOWPUTC</code>: architecture supports low-level, boot
time console output
</li>
<li>
<code>CONFIG_MM_REGIONS</code>: If the architecture includes multiple
regions of memory to allocate from, this specifies the
number of memory regions that the memory manager must
handle and enables the API mm_addregion(start, end);
</li>
<li>
<code>CONFIG_TICKS_PER_MSEC</code>: The default system timer is 100Hz
or <code>TICKS_PER_MSEC</code>=10. This setting may be defined to inform NuttX
that the processor hardware is providing system timer interrupts at some interrupt
interval other than 10 msec.
</li>
<li>
<code>CONFIG_RR_INTERVAL</code>: The round robin timeslice will be set
this number of milliseconds; Round robin scheduling can
be disabled by setting this value to zero.
</li>
<li>
<code>CONFIG_SCHED_INSTRUMENTATION</code>: enables instrumentation in
scheduler to monitor system performance
</li>
<li>
<code>CONFIG_TASK_NAME_SIZE</code>: Spcifies that maximum size of a
task name to save in the TCB. Useful if scheduler
instrumentation is selected. Set to zero to disable.
</li>
<li>
<code>CONFIG_START_YEAR, CONFIG_START_MONTH, CONFIG_START_DAY -
Used to initialize the internal time logic.
</li>
<li>
<code>CONFIG_JULIAN_TIME</code>: Enables Julian time conversions
</li>
<li>
<code>CONFIG_DEV_CONSOLE</code>: Set if architecture-specific logic
provides /dev/console. Enables stdout, stderr, stdin.
</li>
<li>
<code>CONFIG_MUTEX_TYPES</code>: Set to enable support for recursive and
errorcheck mutexes. Enables <code>pthread_mutexattr_settype()</code>.
</li>
<li>
<code>CONFIG_PRIORITY_INHERITANCE</code>: Set to enable support for
priority inheritance on mutexes and semaphores.
Priority inheritance is a strategy of addessing
<a href="NuttxUserGuide.html#priorityinversion"><i>priority inversion</i></a>.
Details of the NuttX implementation of priority inheritance is
discussed <a href="NuttxUserGuide.html#priorityinheritance">elsewhere</a>.
</li>
<li>
<code>CONFIG_SEM_PREALLOCHOLDERS</code>: This setting is only used
if priority inheritance is enabled.
It defines the maximum number of different threads (minus one) that
can take counts on a semaphore with priority inheritance support.
This may be set to zero if priority inheritance is disabled OR if you
are only using semaphores as mutexes (only one holder) OR if no more
than two threads participate using a counting semaphore.
</li>
<li>
<code>CONFIG_SEM_NNESTPRIO</code>: If priority inheritance is enabled,
then this setting is the maximum number of higher priority threads (minus
1) than can be waiting for another thread to release a count on a semaphore.
This value may be set to zero if no more than one thread is expected to
wait for a semaphore.
</li>
</ul>
<p>
The following can be used to disable categories of APIs supported
by the OS. If the compiler supports weak functions, then it
should not be necessary to disable functions unless you want to
restrict usage of those APIs.
</p>
<p>
There are certain dependency relationships in these features.
</p>
<ul>
<li>
<code>mq_notify()</code> logic depends on signals to awaken tasks
waiting for queues to become full or empty.
</li>
<li>
<code>pthread_condtimedwait()</code> depends on signals to wake
up waiting tasks.
</li>
</ul>
<ul>
<code>CONFIG_DISABLE_CLOCK</code>, <code>CONFI_DISABLE_POSIX_TIMERS</code>,
<code>CONFIG_DISABLE_PTHREAD</code>, <code>CONFIG_DISABLE_SIGNALS</code>,
<code>CONFIG_DISABLE_MQUEUE</code>, <code>CONFIG_DISABLE_MOUNTPOUNT</code>
</ul>
<h2>Miscellaneous libc settings</h2>
<ul>
<li>
<code>CONFIG_NOPRINTF_FIELDWIDTH</code>: sprintf-related logic is a
little smaller if we do not support fieldwidthes
</li>
</ul>
<h2>Allow for architecture optimized implementations</h2>
<p>
The architecture can provide optimized versions of the
following to improve sysem performance.
</p>
<ul>
<p>
<code>CONFIG_ARCH_MEMCPY</code>, <code>CONFIG_ARCH_MEMCMP</code>, <code>CONFIG_ARCH_MEMMOVE</code>,
<code>CONFIG_ARCH_MEMSET</code>, <code>CONFIG_ARCH_STRCMP</code>, <code>CONFIG_ARCH_STRCPY</code>,
<code>CONFIG_ARCH_STRNCPY</code>, <code>CONFIG_ARCH_STRLEN</code>, <code>CONFIG_ARCH_BZERO</code>,
<code>CONFIG_ARCH_KMALLOC</code>, <code>CONFIG_ARCH_KZMALLOC</code>, <code>ONFIG_ARCH_KFREE</code>,
</p>
</ul>
<h2>Sizes of configurable things (0 disables)</h2>
<ul>
<li>
<code>CONFIG_MAX_TASKS</code>: The maximum number of simultaneously
active tasks. This value must be a power of two.
</li>
<li>
<code>CONFIG_NPTHREAD_KEYS</code>: The number of items of thread-
specific data that can be retained
</li>
<li>
<code>CONFIG_NFILE_DESCRIPTORS</code>: The maximum number of file
descriptors (one for each open)
</li>
<li>
<code>CONFIG_NFILE_STREAMS</code>: The maximum number of streams that
can be fopen'ed
</li>
<li>
<code>CONFIG_NAME_MAX</code>: The maximum size of a file name.
</li>
<li>
<code>CONFIG_STDIO_BUFFER_SIZE</code>: Size of the buffer to allocate
on fopen. (Only if CONFIG_NFILE_STREAMS > 0)
</li>
<li>
<code>CONFIG_NUNGET_CHARS</code>: Number of characters that can be
buffered by ungetc() (Only if CONFIG_NFILE_STREAMS > 0)
</li>
<li>
<code>CONFIG_PREALLOC_MQ_MSGS</code>: The number of pre-allocated message
structures. The system manages a pool of preallocated
message structures to minimize dynamic allocations
</li>
<li>
<code>CONFIG_MQ_MAXMSGSIZE</code>: Message structures are allocated with
a fixed payload size given by this settin (does not include
other message structure overhead.
</li>
<li>
<code>CONFIG_PREALLOC_WDOGS</code>: The number of pre-allocated watchdog
structures. The system manages a pool of preallocated
watchdog structures to minimize dynamic allocations
</li>
<li>
<code>CONFIG_DEV_PIPE_SIZE</code>: Size, in bytes, of the buffer to allocated
for pipe and FIFO support (default is 1024).
</li>
</ul>
<h2>File Systems</h2>
<ul>
<li>
<code>CONFIG_FS_FAT</code>: Enable FAT filesystem support.
</li>
<li>
<code>CONFIG_FAT_SECTORSIZE</code>: Max supported sector size.
</li>
<li>
<code>CONFIG_FS_ROMFS</code>: Enable ROMFS filesystem support
</li>
</ul>
<h2>SPI-based MMC/SD driver</h2>
<ul>
<li>
<code>CONFIG_MMCSD_NSLOTS</code>: Number of MMC/SD slots supported by the driver. Default is one.
</li>
<li>
<code>CONFIG_MMCSD_READONLY</code>: Provide read-only access. Default is Read/Write
</li>
<li>
<code>CONFIG_MMCSD_SPICLOCK</code>: Maximum SPI clock to drive MMC/SD card. Default is 20MHz.
</li>
</ul>
<h2>Network Support</h2>
<h3>TCP/IP and UDP support via uIP</h2>
<ul>
<li>
<code>CONFIG_NET</code>: Enable or disable all network features
</li>
<li>
<code>CONFIG_NET_IPv6</code>: Build in support for IPv6
</li>
<li>
<code>CONFIG_NSOCKET_DESCRIPTORS</code>: Maximum number of socket descriptors per task/thread.
</li>
<li>
<code>CONFIG_NET_NACTIVESOCKETS</code>: Maximum number of concurrent socket operations (recv, send, etc.).
Default: <code>CONFIG_NET_TCP_CONNS</code>+<code>CONFIG_NET_UDP_CONNS</code>.
</li>
<li>
<code>CONFIG_NET_SOCKOPTS</code>: Enable or disable support for socket options.
</li>
<li>
<code>CONFIG_NET_BUFSIZE</code>: uIP buffer size
</li>
<li>
<code>CONFIG_NET_TCP</code>: TCP support on or off
</li>
<li>
<code>CONFIG_NET_TCP_CONNS</code>: Maximum number of TCP connections (all tasks).
</li>
<li>
<code>CONFIG_NET_TCPBACKLOG</code>:
Incoming connections pend in a backlog until <code>accept()</code> is called.
The size of the backlog is selected when <code>listen()</code> is called.
</li>
<li>
<code>CONFIG_NET_TCP_READAHEAD_BUFSIZE</code>: Size of TCP read-ahead buffers
</li>
<li>
<code>CONFIG_NET_NTCP_READAHEAD_BUFFERS</code>: Number of TCP read-ahead buffers (may be zero)
</li>
<li>
<code>CONFIG_NET_MAX_LISTENPORTS</code>: Maximum number of listening TCP ports (all tasks).
</li>
<li>
<code>CONFIG_NET_TCPURGDATA</code>: Determines if support for TCP urgent data
notification should be compiled in. Urgent data (out-of-band data)
is a rarely used TCP feature that is very seldom would be required.
</li>
<li>
<code>CONFIG_NET_UDP</code>: UDP support on or off
</li>
<li>
<code>CONFIG_NET_UDP_CHECKSUMS</code>: UDP checksums on or off
</li>
<li>
<code>CONFIG_NET_UDP_CONNS</code>: The maximum amount of concurrent UDP connections
</li>
<li>
<code>CONFIG_NET_ICMP</code>: Enable minimal ICMP support. Includes built-in support
for sending replies to received ECHO (ping) requests.
</li>
<li>
<code>CONFIG_NET_ICMP_PING</code>: Provide interfaces to support application level
support for sending ECHO (ping) requests and associating ECHO replies.
</li>
<li>
<code>CONFIG_NET_PINGADDRCONF</code>: Use "ping" packet for setting IP address
</li>
<li>
<code>CONFIG_NET_STATISTICS</code>: uIP statistics on or off
</li>
<li>
<code>CONFIG_NET_RECEIVE_WINDOW</code>: The size of the advertised receiver's window
</li>
<li>
<code>CONFIG_NET_ARPTAB_SIZE</code>: The size of the ARP table
</li>
<li>
<code>CONFIG_NET_BROADCAST</code>: Incoming UDP broadcast support
</li>
<li>
<code>CONFIG_NET_MULTICAST</code>: Outgoing multi-cast address support
</li>
<li>
<code>CONFIG_NET_LLH_LEN</code>: The link level header length
</li>
<li>
<code>CONFIG_NET_FWCACHE_SIZE</code>: number of packets to remember when looking for duplicates
</li>
</ul>
<h3>UIP Network Utilities</h3>
<ul>
<li>
<code>CONFIG_NET_DHCP_LIGHT</code>: Reduces size of DHCP
</li>
<li>
<code>CONFIG_NET_RESOLV_ENTRIES</code>: Number of resolver entries
</li>
</ul>
<h2>USB Device-Side Support</h2>
<h3>USB Device Controller Driver</h3>
<ul>
<li>
<code>CONFIG_USBDEV</code>: Enables USB device support
</li>
<li>
<code>CONFIG_USBDEV_ISOCHRONOUS</code>: Build in extra support for isochronous endpoints
</li>
<li>
<code>CONFIG_USBDEV_DUALSPEED</code>: Hardware handles high and full speed operation (USB 2.0)
</li>
<li>
<code>CONFIG_USBDEV_SELFPOWERED</code>: Will cause USB features to indicate that the device is self-powered
</li>
<li>
<code>CONFIG_USBDEV_MAXPOWER</code>: Maximum power consumption in mA
</li>
<li>
<code>CONFIG_USBDEV_TRACE</code>: Enables USB tracing for debug
</li>
<li>
<code>CONFIG_USBDEV_TRACE_NRECORDS</code>: Number of trace entries to remember
</li>
</ul>
<h3>USB Serial Device Class Driver</h3>
<ul>
<li>
<code>CONFIG_USBSER</code>: Enable compilation of the USB serial driver
</li>
<li>
<code>CONFIG_USBSER_EPINTIN</code>: The logical 7-bit address of a hardware endpoint that supports interrupt IN operation
</li>
<li>
<code>CONFIG_USBSER_EPBULKOUT</code>: The logical 7-bit address of a hardware endpoint that supports bulk OUT operation
</li>
<li>
<code>CONFIG_USBSER_EPBULKIN</code>: The logical 7-bit address of a hardware endpoint that supports bulk IN operation
</li>
<li>
<code>CONFIG_USBSER_NWRREQS</code> and <code>CONFIG_USBSER_NRDREQS</code>: The number of write/read requests that can be in flight
</li>
<li>
<code>CONFIG_USBSER_VENDORID</code> and <code>CONFIG_USBSER_VENDORSTR</code>: The vendor ID code/string
</li>
<li>
<code>CONFIG_USBSER_PRODUCTID</code> and <code>CONFIG_USBSER_PRODUCTSTR</code>: The product ID code/string
</li>
<li>
<code>CONFIG_USBSER_RXBUFSIZE</code> and <code>CONFIG_USBSER_TXBUFSIZE</code>: Size of the serial receive/transmit buffers
</li>
</ul>
<h3>USB Storage Device Configuration</h3>
<ul>
<li>
<code>CONFIG_USBSTRG</code>:
Enable compilation of the USB storage driver
</li>
<li>
<code>CONFIG_USBSTRG_EP0MAXPACKET</code>:
Max packet size for endpoint 0
</li>
<li>
<code>CONFIG_USBSTRGEPBULKOUT</code> and <code>CONFIG_USBSTRG_EPBULKIN</code>:
The logical 7-bit address of a hardware endpoints that support bulk OUT and IN operations
</li>
<li>
<code>CONFIG_USBSTRG_NWRREQS</code> and <code>CONFIG_USBSTRG_NRDREQS</code>:
The number of write/read requests that can be in flight
</li>
<li>
<code>CONFIG_USBSTRG_BULKINREQLEN</code> and <code>CONFIG_USBSTRG_BULKOUTREQLEN</code>:
The size of the buffer in each write/read request.
This value needs to be at least as large as the endpoint maxpacket and
ideally as large as a block device sector.
</li>
<li>
<code>CONFIG_USBSTRG_VENDORID</code> and <code>CONFIG_USBSTRG_VENDORSTR</code>:
The vendor ID code/string
</li>
<li>
<code>CONFIG_USBSTRG_PRODUCTID</code> and <code>CONFIG_USBSTRG_PRODUCTSTR</code>:
The product ID code/string
</li>
<li>
<code>CONFIG_USBSTRG_REMOVABLE</code>:
Select if the media is removable
</li>
</ul>
<h2>Graphics related configuration settings</h3>
<ul>
<li>
<code>CONFIG_NX</code>
Enables overall support for graphics library and NX
</li>
</ul>
<h3>NX configuration setting</h3>
<ul>
<li>
<code>CONFIG_NX_MULTIUSER</code>:
Configures NX in multi-user mode.
</li>
<li>
<code>CONFIG_NX_NPLANES</code>:
Some YUV color formats requires support for multiple planes,
one for each color component. Unless you have such special
hardware, this value should be undefined or set to 1.
</li>
<li>
<code>CONFIG_NX_DISABLE_1BPP</code>, <code>CONFIG_NX_DISABLE_2BPP</code>,
<code>CONFIG_NX_DISABLE_4BPP</code>, <code>CONFIG_NX_DISABLE_8BPP</code>
<code>CONFIG_NX_DISABLE_16BPP</code>, <code>CONFIG_NX_DISABLE_24BPP</code>, and
<code>CONFIG_NX_DISABLE_32BPP</code>:
NX supports a variety of pixel depths. You can save some
memory by disabling support for unused color depths.
</li>
<li>
<code>CONFIG_NX_PACKEDMSFIRST</code>:
If a pixel depth of less than 8-bits is used, then NX needs
to know if the pixels pack from the MS to LS or from LS to MS
</li>
<li>
<code>CONFIG_NX_MOUSE</code>:
Build in support for mouse input.
</li>
<li>
<code>CONFIG_NX_KBD</code>:
Build in support of keypad/keyboard input.
</li>
<li>
<code>CONFIG_NXTK_BORDERWIDTH</code>:
Specifies with with of the border (in pixels) used with
framed windows. The default is 4.
</li>
<li>
<code>CONFIG_NXTK_BORDERCOLOR1</code> and <code>CONFIG_NXTK_BORDERCOLOR2</code>:
Specify the colors of the border used with framed windows.
<code>CONFIG_NXTK_BORDERCOLOR2</code> is the shadow side color and so
is normally darker. The default is medium and dark grey,
respectively
</li>
<li>
<code>CONFIG_NXTK_AUTORAISE</code>:
If set, a window will be raised to the top if the mouse position
is over a visible portion of the window. Default: A mouse
button must be clicked over a visible portion of the window.
</li>
<li>
<code>CONFIG_NXFONTS_CHARBITS</code>:
The number of bits in the character set. Current options are
only 7 and 8. The default is 7.
</li>
<li>
<code>CONFIG_NXFONT_SANS</code>:
At present, there is only one font. But if there were were more,
then this option would select the sans serif font.
</li>
</ul>
<h3>NX Multi-user only options</h3>
<ul>
<li>
<code>CONFIG_NX_BLOCKING</code>
Open the client message queues in blocking mode. In this case,
<code>nx_eventhandler()</code> will not return until a message is received and processed.
</li>
<li>
<code>CONFIG_NX_MXSERVERMSGS</code> and <code>CONFIG_NX_MXCLIENTMSGS</code>
Specifies the maximum number of messages that can fit in
the message queues. No additional resources are allocated, but
this can be set to prevent flooding of the client or server with
too many messages (<code>CONFIG_PREALLOC_MQ_MSGS</code> controls how many
messages are pre-allocated).
</li>
</ul>
<h2>Stack and heap information</h2>
<ul>
<li>
<code>CONFIG_BOOT_RUNFROMFLASH</code>: Some configurations support XIP
operation from FLASH but must copy initialized .data sections to RAM.
</li>
<li>
<code>CONFIG_BOOT_COPYTORAM</code>: Some configurations boot in FLASH
but copy themselves entirely into RAM for better performance.
</li>
<li>
<code>CONFIG_STACK_POINTER</code>: The initial stack pointer
</li>
<li>
<code>CONFIG_IDLETHREAD_STACKSIZE</code>: The size of the initial stack.
This is the thread that (1) performs the inital boot of the system up
to the point where user_start() is spawned, and (2) there after is the
IDLE thread that executes only when there is no other thread ready to
run.
</li>
<li>
<code>CONFIG_USERMAIN_STACKSIZE</code>: The size of the stack to allocate
for the main user thread that begins at the user_start() entry point.
</li>
<li>
<code>CONFIG_PTHREAD_STACK_MIN</code>: Minimum pthread stack size
</li>
<li>
<code>CONFIG_PTHREAD_STACK_DEFAULT</code>: Default pthread stack size
</li>
<li>
<code>CONFIG_HEAP_BASE</code>: The beginning of the heap
</li>
<li>
<code>CONFIG_HEAP_SIZE</code>: The size of the heap
</li>
</ul>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<h1><a name="apndxtrademarks">Appendix B: Trademarks</a></h1>
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<li>ARM, ARM7 ARM7TDMI, ARM9, ARM920T, ARM926EJS, Cortex-M3 are trademarks of Advanced RISC Machines, Limited.</li>
<li>Cygwin is a trademark of Red Hat, Incorporated.</li>
<li>Linux is a registered trademark of Linus Torvalds.</li>
<li>Eagle-100 is a trademark of <a href=" http://www.micromint.com/">Micromint USA, LLC</a>.
<li>LPC2148 is a trademark of NXP Semiconductors.</li>
<li>TI is a tradename of Texas Instruments Incorporated.</li>
<li>UNIX is a registered trademark of The Open Group.</li>
<li>VxWorks is a registered trademark of Wind River Systems, Incorporated.</li>
<li>ZDS, ZNEO, Z16F, Z80, and Zilog are a registered trademark of Zilog, Inc.</li>
<p>
NOTE: NuttX is <i>not</i> licensed to use the POSIX trademark. NuttX uses the POSIX
standard as a development guideline only.
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