hobbielektronika / Mbed 2 deprecated 10_rtos_signals

Synchronize two tasks by the help of event signals. Watch the output in a Terminal window!

Dependencies:   mbed-rtos mbed

main.cpp@0:6c4ab9386095, 2016-02-23 (annotated)

Committer:
icserny
Date:
Tue Feb 23 13:27:53 2016 +0000
Revision:
0:6c4ab9386095
First version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
icserny 0:6c4ab9386095 1 /** 10_rtos_signals
icserny 0:6c4ab9386095 2 *
icserny 0:6c4ab9386095 3 * Synchronize two tasks by the help of event signals.
icserny 0:6c4ab9386095 4 * Thread2 changes the state of LED1 when any event flag arrives.
icserny 0:6c4ab9386095 5 * Thread1 (the main thread) sends event flags at reguar intervals.
icserny 0:6c4ab9386095 6 * You may experimenting by changeing this program:
icserny 0:6c4ab9386095 7 * - Wait for a given flag: for example Thread::signal_wait(0x8);
icserny 0:6c4ab9386095 8 * - Wait for multiple events: for example Thread::signal_wait(0x5);
icserny 0:6c4ab9386095 9 * - Wait for a nonexistent events: for example Thread::signal_wait(0x10000);
icserny 0:6c4ab9386095 10 * - Wait for a limited time: for example Thread::signal_wait(0x3,500);
icserny 0:6c4ab9386095 11 *
icserny 0:6c4ab9386095 12 * Watch the output in a Terminal window!
icserny 0:6c4ab9386095 13 */
icserny 0:6c4ab9386095 14
icserny 0:6c4ab9386095 15 #include "mbed.h"
icserny 0:6c4ab9386095 16 #include "rtos.h"
icserny 0:6c4ab9386095 17
icserny 0:6c4ab9386095 18 DigitalOut led(LED1);
icserny 0:6c4ab9386095 19
icserny 0:6c4ab9386095 20 void led_thread(void const *argument)
icserny 0:6c4ab9386095 21 {
icserny 0:6c4ab9386095 22 while (true) {
icserny 0:6c4ab9386095 23 // Signal flags that are reported as event are automatically cleared.
icserny 0:6c4ab9386095 24 osEvent evt = Thread::signal_wait(0); //Wait for any signal
icserny 0:6c4ab9386095 25 switch(evt.status) {
icserny 0:6c4ab9386095 26 case osOK:
icserny 0:6c4ab9386095 27 printf("osOK\n"); //no error or event occurred
icserny 0:6c4ab9386095 28 break;
icserny 0:6c4ab9386095 29 case osEventSignal:
icserny 0:6c4ab9386095 30 printf("osEventSignal = %#05x\n",evt.value.signals); //signal event occurred
icserny 0:6c4ab9386095 31 break;
icserny 0:6c4ab9386095 32 case osEventTimeout:
icserny 0:6c4ab9386095 33 printf("osEventTimeout\n"); //timeout occurred
icserny 0:6c4ab9386095 34 break;
icserny 0:6c4ab9386095 35 case osErrorValue:
icserny 0:6c4ab9386095 36 printf("osErrorValue\n");
icserny 0:6c4ab9386095 37 break; //value of a parameter is out of range.
icserny 0:6c4ab9386095 38 default:
icserny 0:6c4ab9386095 39 printf("Unknown error flag: %#08x\n",(uint32_t)evt.status);
icserny 0:6c4ab9386095 40 break;
icserny 0:6c4ab9386095 41 };
icserny 0:6c4ab9386095 42 led = !led;
icserny 0:6c4ab9386095 43 }
icserny 0:6c4ab9386095 44 }
icserny 0:6c4ab9386095 45
icserny 0:6c4ab9386095 46 int main (void)
icserny 0:6c4ab9386095 47 {
icserny 0:6c4ab9386095 48 int32_t signal_mask = 0x1;
icserny 0:6c4ab9386095 49 Thread thread2(led_thread);
icserny 0:6c4ab9386095 50
icserny 0:6c4ab9386095 51 while (true) {
icserny 0:6c4ab9386095 52 Thread::wait(1000);
icserny 0:6c4ab9386095 53 thread2.signal_set(signal_mask); //send signals from 0x0001 to 0x8000
icserny 0:6c4ab9386095 54 signal_mask <<=1; //switch to next signal
icserny 0:6c4ab9386095 55 if(signal_mask > 0x8000) signal_mask=0x1;
icserny 0:6c4ab9386095 56 }
icserny 0:6c4ab9386095 57 }