István Cserny / Mbed 2 deprecated Lab08_rtos_signals

In this example the first thread (the main () function) sends signals to the second thread at regular intervals. The second thread waits until an event signal does not arrive. Each time the signal arrives, the program toggles the status of LED1. Note, that the return value of the Thread :: signal_wait () function is examined and is printed out as well. Just for fun thread2: accepts any signal, and thead1 provides all possible signals from 1 to 32768.

Dependencies:   mbed mbed-rtos

main.cpp

Committer:
cspista
Date:
2022-03-17
Revision:
0:bd08296227ad

File content as of revision 0:bd08296227ad:

#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");                   //value of a parameter is out of range
        break;               
      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);
    signal_mask <<=1;
    if(signal_mask > 0x8000) signal_mask=0x1;
  }
}