Revision 9:31031bbb59c7, committed 2016-03-21

Comitter:

noutram

Date:

Mon Mar 21 13:50:11 2016 +0000

Parent:

8:c5663f5fa848

Child:

10:3a3d2a571c8f

Commit message:

Task631 - simple message queue between an interrupt and a thread

Changed in this revision

--- a/main.cpp	Mon Mar 14 19:48:24 2016 +0000
+++ b/main.cpp	Mon Mar 21 13:50:11 2016 +0000
@@ -10,15 +10,15 @@
 void thread2( const void*  );
 void switchISR();
 
+//Analogue inputs
+AnalogIn adcIn(A0);
+
 //Digital outputs
 DigitalOut onBoardLED(LED1);
 DigitalOut redLED(D7);
 DigitalOut yellowLED(D6);
 DigitalOut greenLED(D5);
 
-//Serial Interface
-Serial pc(USBTX, USBRX);
-
 //Digital inputs
 DigitalIn  onBoardSwitch(USER_BUTTON);
 DigitalIn  sw1(D4);                         //CONSIDER CHANGING THIS TO AN INTERRUPT
@@ -26,50 +26,60 @@
 
 //Threads
 Thread *t1;
-Thread *t2;
 
-//Thread ID for the Main function (CMSIS API)
-osThreadId tidMain;
-osThreadId tid1;
-osThreadId tid2;
+//Queues - "A message can be a integer or pointer value  to a certain type T that is sent to a thread or interrupt service routine."
+Queue<uint32_t, 5> *queue;
 
 
-//TBD: Call this on the falling edge of SW1
-void switchISR() {
-     //TBD
+// Call this on precise intervals
+void adcISR() {
+    
+    //Option to starve the queue
+    if (sw2 == 1) return;
+    
+    //Read sample - make a copy
+    uint32_t sample = (uint32_t)(4095*adcIn.read());
+    
+    //Write to queue
+    osStatus stat = queue->put((uint32_t*)sample);
+    
+    //Check if succesful
+    if (stat == osErrorResource) {
+        redLED = 1; 
+        printf("queue->put() Error code: %4Xh, Resource not available\r\n", stat);   
+    }
+    
 }
 
-//High priority thread
+//Normal priority thread (consumer)
 void thread1( const void* arg ) 
-{
-    redLED = 1;
+{    
     while (true) {
-         
-         // THIS IS BAD BAD BAD BAD BAD BAD
-         // BLOCK ON FALLING EDGE OF SW1 BY RAPID POLLING (SPINNING)
-         // Thread is blocked in the RUNNING state 
-         while (sw1 == 0);
-         wait_ms(200);      //Wait for debounce
-         while (sw1 == 1);
-         // TODO: FIX THIS! GET THE INTERRUPT TO SIGNAL THIS THREAD
-         
-         redLED = !redLED;
-         Thread::wait(1000);    //Thread in WAITING state
-         redLED = !redLED;
-         Thread::wait(1000);    //Thread in WAITING state
-    }
-}
-
-// This thread has normal priority 
-// It is supposed to flash the green LED every second.
-// THIS IS NOT WORKING because it is currently being starved by thread1 (while polling the switch)
-void thread2( const void* arg ) 
-{
-    greenLED = 1; 
-    while (true) {   
-        Thread::wait(500);
-        greenLED = !greenLED;
-    }
+        //Read queue - block (with timeout)
+        osEvent evt = queue->get(5000);     //With timeout
+        
+        //Check status of get()
+        switch (evt.status) { 
+            case osEventMessage:
+                //Normal status
+                printf("value = %d\n\r", evt.value.v);
+                greenLED = !greenLED;
+                break;
+            case osEventTimeout:
+                //Timeout
+                printf("queue->get() returned %02x status (timeout)\n\r", evt.status);
+                break;
+            default:
+                //All other errors (see cmsis_os.h for meaning of error code)
+                printf("queue->get() returned %02x status\n\r", evt.status);
+                break;
+        }
+                
+        //Block up consumer if switch is held down
+        //Will fill the queue if held long enough
+        while (sw1 == 1);
+        
+    } //end while
 }
 
 
@@ -79,20 +89,23 @@
     yellowLED = 0;
     greenLED  = 0;
            
+    //Start message
+    printf("Welcome\n");
+           
+    //Queue
+    queue = new Queue<uint32_t,5>();
+
+    //Hook up timer interrupt   
+    Ticker timer; 
+    timer.attach(&adcISR, 1.0);
+               
     //Threads
-    t1 = new Thread(&thread1, NULL, osPriorityRealtime);    //HIGH PRIORITY
-    t2 = new Thread(&thread2, NULL, osPriorityNormal);              
-              
-    // Thread IDs
-    tidMain = Thread::gettid();  
-    tid1    = t1->gettid();
-    tid2    = t2->gettid();
+    t1 = new Thread(&thread1); 
     
-    //TBD: Hook up interrupt    
-        
-    pc.printf("Main Thread\n");
+    printf("Main Thread\n");
     while (true) {
-        Thread::wait(osWaitForever);
+        Thread::wait(5000);
+        puts("Main Thread Alive");
     }
 }