Embedded System Tutorial FreeRTOS - Revision history

Sree at 20:11, 25 January 2019

2019-01-25T20:11:27Z

Preet: /* Assignment */

2016-03-14T05:56:27Z

‎Assignment

Preet: /* Assignment */

2015-03-08T00:47:45Z

‎Assignment

Preet: /* C++ Task */

2014-03-18T22:50:56Z

‎C++ Task

Preet: /* C++ Task */

2014-03-18T22:48:18Z

‎C++ Task

Preet: /* C++ Task */

2014-03-18T22:47:42Z

‎C++ Task

Preet at 16:32, 5 March 2014

2014-03-05T16:32:10Z

Preet: /* Assignment */

2014-02-19T00:11:09Z

‎Assignment

Preet: /* Assignment */

2014-02-19T00:10:10Z

‎Assignment

Preet: /* Assignment */

2014-02-19T00:00:33Z

‎Assignment

@@ Line 1: / Line 1: @@
 The objective of this assignment is to show you how to create a FreeRTOS task a few different ways.  The [[FreeRTOS Tutorial]] is definitely a must read before going through this lesson.
@@ Line 148: / Line 156: @@
+}
 </syntaxhighlight>

@@ Line 108: / Line 108: @@
 This assignment is based on SJ-One board, but you can alter the requirement to fit your own hardware.
 #  Create a task (task1) that computes the orientation of the board.
 #:   Send the orientation enumeration, such as "up", "down", "left", "right" to a queue every 1 second
 #  Create another task (task2) that waits on the queued item

@@ Line 116: / Line 116: @@
 #:   Use the same priority for both tasks, and note down the order of the print-outs
 #:   Use higher priority for the receiving task, and note down the order of the print-outs.
-#  Create a terminal task with a command "orientation on" and "orientation off"
+#  Create a terminal command: "orientation on" and "orientation off"
 #:   If orientation is commanded on, resume the task1, otherwise suspend it
 #:   See code below on hints of how this command can get control of another task.

@@ Line 50: / Line 50: @@
          orient_compute(uint8_t priority) : scheduler_task("compute", 2048, priority)
+         {
              QueueHandle_t my_queue = xQueueCreate(1, sizeof(orientation_t));
              addSharedObject(shared_SensorQueueId, my_queue);
@@ Line 75: / Line 76: @@
          bool run(void *p)
+         {
              orientation_t orientation = invalid;
              QueueHandle_t qid = getSharedObject(shared_SensorQueueId);

@@ Line 33: / Line 33: @@
 <syntaxhighlight lang="cpp">
 typedef enum {
     shared_SensorQueueId,
 } sharedHandleId_t;
 typedef enum {
      invalid,

@@ Line 32: / Line 32: @@
 === C++ Task ===
 <syntaxhighlight lang="cpp">
 class orient_compute : public scheduler_task
+{
      public:
-         orient_compute(uint8_t priority) : scheduler_task("compute", 512, priority)
+         orient_compute(uint8_t priority) : scheduler_task("compute", 2048, priority)
+         {
-             QueueHandle_t my_queue = xQueueCreate(1, sizeof(int));
+             QueueHandle_t my_queue = xQueueCreate(1, sizeof(orientation_t));
-             addSharedObject("queue_id", my_queue);
+             addSharedObject(shared_SensorQueueId, my_queue);
+         }
@@ Line 44: / Line 55: @@
+         {
              /* Compute orientation here, and send it to the queue once a second */
-             int orientation = 0;
+             orientation_t orientation = invalid;
-             xQueueSend(getSharedObject("queue_id"), &orientation, 999999);
+             xQueueSend(getSharedObject(shared_SensorQueueId), &orientation, portMAX_DELAY);
              vTaskDelay(1000);
              return true;
@@ Line 54: / Line 66: @@
+{
      public:
-         orient_process (uint8_t priority) : scheduler_task("process", 512, priority)
+         orient_process (uint8_t priority) : scheduler_task("process", 2048, priority)
+         {
              /* Nothing to init */
@@ Line 61: / Line 73: @@
          bool run(void *p)
+         {
              /* Sleep the task forever until an item is available in the queue */
-            int orientation = 0;
+             if (xQueueReceive(qid, &orientation, portMAX_DELAY))
+             {
+             }
              return true;
+         }

@@ Line 37: / Line 37: @@
          orient_compute(uint8_t priority) : scheduler_task("compute", 512, priority)
+         {
-             xQueueHandle my_queue = xQueueCreate(1, sizeof(int));
+             QueueHandle_t my_queue = xQueueCreate(1, sizeof(int));
              addSharedObject("queue_id", my_queue);
+         }
@@ Line 108: / Line 108: @@
 bool terminalTask::taskEntry()
+{
-    // When command handler is called, give the orientation tasks' pointer to it:
+     cp.addHandler(orientationCmd,  "orientation", "Two options: 'orientation on' or 'orientation off'");
+}
@@ Line 117: / Line 115: @@
+{
      // Our parameter was the orientation tasks' pointer, but you may want to check for NULL pointer first.
-     scheduler_task *orientTask = (scheduler_task*) pDataParam;
+     scheduler_task *compute = scheduler_task::getTaskPtrByName("compute");
      // You can use FreeRTOS API or the wrapper resume() or suspend() methods
      if (cmdParams == "on") {
-         vTaskResume(orientTask->getTaskHandle());  // Can also use: orintTask->resume();
+         vTaskResume(compute->getTaskHandle());  // Can also use: compute->resume();
+     }
      else {
-         vTaskSuspend(orientTask->getTaskHandle()); // Can also use: orintTask->suspend();
+         vTaskSuspend(compute->getTaskHandle()); // Can also use: compute->suspend();
+     }

@@ Line 102: / Line 102: @@
 #  Answer the following questions:
 #:   What if you use ZERO block time while sending an item to the queue, will that make any difference?
 #:   What is the purpose of the block time during xQueueReceive() ?