---
title: nuttx
categories: embedded, arm, stm32, stm32f429
toc: no
...

組員
----
* 翁振育
* 黃亮穎
* 蘇偉嘉
* 李英碩

Nuttx 參考應用
---------------
* `PX4 autopilot<http://pixhawk.org/dev/nuttx/start>`_

NuttX 架構
------------
＊ 可混用task跟thread。
＊ 支援FPU。
＊ 可混用FIFO跟RR。

與平台相關
------------

Run Nuttx on STM32F429-Disco
----------------------------------------------
| (1) 從 https://github.com/deadbeefcafe/nuttx-stm32f4disc-bb 複製Nuttx到workspace
| (2) cd workspace/nuttx-stm32f4disc-bb/nuttx/tools
| (3) ./configure.sh stm32f429i-disco/nsh
| (4) cd ..
| (5) make CROSSDEV=arm-none-eabi- 
| (6) st-flash write nuttx.bin 0x8000000
| (7) sudo screen /dev/ttyUSB0 115200 8n1

Task state
------------
include/nuttx/sched.h

.. code-block:: c

 enum tstate_e
 {
     TSTATE_TASK_INVALID    = 0, /* INVALID      - The TCB is uninitialized */
     TSTATE_TASK_PENDING,        /* READY_TO_RUN - Pending preemption unlock */
     TSTATE_TASK_READYTORUN,     /* READY-TO-RUN - But not running */
     TSTATE_TASK_RUNNING,        /* READY_TO_RUN - And running */
     TSTATE_TASK_INACTIVE,       /* BLOCKED      - Initialized but not yet activated */
     TSTATE_WAIT_SEM,            /* BLOCKED      - Waiting for a semaphore */
  #ifndef CONFIG_DISABLE_SIGNALS
     TSTATE_WAIT_SIG,            /* BLOCKED      - Waiting for a signal */
  #endif
  #ifndef CONFIG_DISABLE_MQUEUE
     TSTATE_WAIT_MQNOTEMPTY,     /* BLOCKED      - Waiting for a MQ to become not empty. */
     TSTATE_WAIT_MQNOTFULL,      /* BLOCKED      - Waiting for a MQ to become not full. */
  #endif
  #ifdef CONFIG_PAGING
     TSTATE_WAIT_PAGEFILL,       /* BLOCKED      - Waiting for page fill */
  #endif
     NUM_TASK_STATES             /* Must be last */
 };

Task list 
------------
sched/os_internal.h

.. code-block:: c

  typedef struct tasklist_s tasklist_t;
   

  extern volatile dq_queue_t g_pendingtasks;
  extern volatile dq_queue_t g_waitingforsemaphore;
  #ifndef CONFIG_DISABLE_SIGNALS
  extern volatile dq_queue_t g_waitingforsignal;
  #endif
  #ifndef CONFIG_DISABLE_MQUEUE
  extern volatile dq_queue_t g_waitingformqnotempty;
  #endif
  #ifndef CONFIG_DISABLE_MQUEUE
  extern volatile dq_queue_t g_waitingformqnotfull;
  #endif
  #ifdef CONFIG_PAGING
  extern volatile dq_queue_t g_waitingforfill;
  #endif
  extern volatile dq_queue_t g_inactivetasks;
  extern volatile sq_queue_t g_delayed_kufree;
  #if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
  extern volatile sq_queue_t g_delayed_kfree;
  #endif
  extern volatile pid_t g_lastpid;
  extern pidhash_t g_pidhash[CONFIG_MAX_TASKS];
  extern const tasklist_t g_tasklisttable[NUM_TASK_STATES];
 
TCB 
------------
include/nuttx/sched.h

.. code-block:: c

 struct tcb_s
 {
   /* Fields used to support list management *************************************/
   FAR struct tcb_s *flink;               /* Doubly linked list */
   FAR struct tcb_s *blink;
  
   /* Task Management Fields *****************************************************/
 
   pid_t    pid;                          /* This is the ID of the thread        */
 
   start_t  start;                        /* Thread start function               */
   entry_t  entry;                        /* Entry Point into the thread         */
   uint8_t  sched_priority;               /* Current priority of the thread      */
 
   uint8_t  task_state;                   /* Current state of the thread         */
   uint16_t flags;                        /* Misc. general status flags          */
   int16_t  lockcount;                    /* 0=preemptable (not-locked)          */

  #if CONFIG_RR_INTERVAL > 0
    int      timeslice;                    /* RR timeslice interval remaining     */
  #endif

   /* Stack-Related Fields *******************************************************/

  #ifndef CONFIG_CUSTOM_STACK
    size_t    adj_stack_size;              /* Stack size after adjustment         */
                                          /* for hardware, processor, etc.       */
                                          /* (for debug purposes only)           */
    FAR void *stack_alloc_ptr;             /* Pointer to allocated stack          */
                                           /* Need to deallocate stack            */
    FAR void *adj_stack_ptr;               /* Adjusted stack_alloc_ptr for HW     */
                                          /* The initial stack pointer value     */
  #endif
 
  
    /* POSIX Semaphore Control Fields *********************************************/
 
   sem_t *waitsem;                        /* Semaphore ID waiting on             */
 
   /* POSIX Signal Control Fields ************************************************/
 
 #ifndef CONFIG_DISABLE_SIGNALS
   sigset_t   sigprocmask;                /* Signals that are blocked            */
   sigset_t   sigwaitmask;                /* Waiting for pending signals         */
   sq_queue_t sigactionq;                 /* List of actions for signals         */
   sq_queue_t sigpendactionq;             /* List of pending signal actions      */
   sq_queue_t sigpostedq;                 /* List of posted signals              */
   siginfo_t  sigunbinfo;                 /* Signal info when task unblocked     */
 #endif
 
   /* POSIX Named Message Queue Fields *******************************************/
 
 #ifndef CONFIG_DISABLE_MQUEUE
   FAR msgq_t *msgwaitq;                  /* Waiting for this message queue      */
 #endif
 
 
   /* The form and content of these fields are processor-specific.               */
 
   struct xcptcontext xcp;                /* Interrupt register save area        */
 
 #if CONFIG_TASK_NAME_SIZE > 0
   char name[CONFIG_TASK_NAME_SIZE];      /* Task name                           */
 #endif
                                                   :
                                                   : 
                                                   : 
                                                   :
                                                   :
                                                   :
 };
 
Communication
---------------------
 
Scheduling
----------------
 
Interrupt handler
------------------------
 
測試環境架設
------------

硬體驅動原理
------------
* `UART<embedded/USART>`_
* FPU (Floating Point Unit)

效能表現
--------

參考資料
--------
* https://github.com/deadbeefcafe/nuttx-stm32f4disc-bb
* http://bibliodigital.itcr.ac.cr/xmlui/bitstream/handle/2238/3051/FinalReport.pdf