Diff: main.cpp

Revision:

0:6c4ab9386095

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Feb 23 13:27:53 2016 +0000
@@ -0,0 +1,57 @@
+/** 10_rtos_signals
+ *
+ * Synchronize two tasks by the help of event signals.
+ * Thread2 changes the state of LED1 when any event flag arrives.
+ * Thread1 (the main thread) sends event flags at reguar intervals.
+ * You may experimenting by changeing this program:
+ *  - Wait for a given flag: for example Thread::signal_wait(0x8);  
+ *  - Wait for multiple events: for example Thread::signal_wait(0x5);
+ *  - Wait for a nonexistent events: for example Thread::signal_wait(0x10000);
+ *  - Wait for a limited time: for example Thread::signal_wait(0x3,500);
+ *
+ * Watch the output in a Terminal window!
+ */
+
+#include "mbed.h"
+#include "rtos.h"
+
+DigitalOut led(LED1);
+
+void led_thread(void const *argument)
+{
+    while (true) {
+        // Signal flags that are reported as event are automatically cleared.
+        osEvent evt = Thread::signal_wait(0);                           //Wait for any signal
+        switch(evt.status) {
+            case osOK:
+                printf("osOK\n");                                       //no error or event occurred
+                break;
+            case osEventSignal:
+                printf("osEventSignal = %#05x\n",evt.value.signals);    //signal event occurred
+                break;              
+            case osEventTimeout:
+                printf("osEventTimeout\n");                             //timeout occurred
+                break;               
+            case osErrorValue:
+                printf("osErrorValue\n");
+                break;                                                  //value of a parameter is out of range.               
+            default:
+                printf("Unknown error flag: %#08x\n",(uint32_t)evt.status);
+                break;
+        };
+        led = !led;
+    }
+}
+
+int main (void)
+{
+    int32_t signal_mask = 0x1;
+    Thread thread2(led_thread);
+
+    while (true) {
+        Thread::wait(1000);
+        thread2.signal_set(signal_mask);                                //send signals from 0x0001 to 0x8000
+        signal_mask <<=1;                                               //switch to next signal
+        if(signal_mask > 0x8000) signal_mask=0x1;
+    }
+}