NuttxPortingGuide.html

    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 time slice 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>: Specifies 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 addressing
    <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 system 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 setting (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 initial 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>
    </td>
  </tr>
</table>

  <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 trade name 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.
</p>

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