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@0:bd08296227ad, 2022-03-17 (annotated)

Committer:
cspista
Date:
Thu Mar 17 12:43:28 2022 +0000
Revision:
0:bd08296227ad
Final version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
cspista 0:bd08296227ad 1 #include "mbed.h"
cspista 0:bd08296227ad 2 #include "rtos.h"
cspista 0:bd08296227ad 3
cspista 0:bd08296227ad 4 DigitalOut led(LED1);
cspista 0:bd08296227ad 5
cspista 0:bd08296227ad 6 void led_thread(void const *argument) {
cspista 0:bd08296227ad 7 while (true) {
cspista 0:bd08296227ad 8 // Signal flags that are reported as event are automatically cleared.
cspista 0:bd08296227ad 9 osEvent evt = Thread::signal_wait(0); //Wait for any signal
cspista 0:bd08296227ad 10 switch(evt.status) {
cspista 0:bd08296227ad 11 case osOK:
cspista 0:bd08296227ad 12 printf("osOK\n"); //no error or event occurred
cspista 0:bd08296227ad 13 break;
cspista 0:bd08296227ad 14 case osEventSignal:
cspista 0:bd08296227ad 15 printf("osEventSignal = %#05x\n",evt.value.signals); //signal event occurred
cspista 0:bd08296227ad 16 break;
cspista 0:bd08296227ad 17 case osEventTimeout:
cspista 0:bd08296227ad 18 printf("osEventTimeout\n"); //timeout occurred
cspista 0:bd08296227ad 19 break;
cspista 0:bd08296227ad 20 case osErrorValue:
cspista 0:bd08296227ad 21 printf("osErrorValue\n"); //value of a parameter is out of range
cspista 0:bd08296227ad 22 break;
cspista 0:bd08296227ad 23 default:
cspista 0:bd08296227ad 24 printf("Unknown error flag: %#08x\n",(uint32_t)evt.status);
cspista 0:bd08296227ad 25 break;
cspista 0:bd08296227ad 26 };
cspista 0:bd08296227ad 27 led = !led;
cspista 0:bd08296227ad 28 }
cspista 0:bd08296227ad 29 }
cspista 0:bd08296227ad 30
cspista 0:bd08296227ad 31 int main (void) {
cspista 0:bd08296227ad 32 int32_t signal_mask = 0x1;
cspista 0:bd08296227ad 33 Thread thread2(led_thread);
cspista 0:bd08296227ad 34 while (true) {
cspista 0:bd08296227ad 35 Thread::wait(1000);
cspista 0:bd08296227ad 36 thread2.signal_set(signal_mask);
cspista 0:bd08296227ad 37 signal_mask <<=1;
cspista 0:bd08296227ad 38 if(signal_mask > 0x8000) signal_mask=0x1;
cspista 0:bd08296227ad 39 }
cspista 0:bd08296227ad 40 }