This example shows how to use multiple signals from the main thread in mbed-os.
The sample sets up two Tickers to generate periodic interrupts. Each ticker sets a signal during an interrupt.
osSignalWait(signal, timeout) is used to wait for an event. Set signal to 0 to exit on any signal or set signal to a mask value to only exit if all of the signals are set.
Diff: main.cpp
- Revision:
- 0:677614c5f014
- Child:
- 1:907cf114c40c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Thu Sep 08 21:17:19 2016 +0000
@@ -0,0 +1,80 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX);
+Ticker tick1;
+Ticker tick2;
+DigitalOut led1(LED_RED,true);
+DigitalOut led2(LED_GREEN,true);
+osThreadId mainThread;
+
+void interrupt1()
+{
+ osSignalSet(mainThread, 0x1);
+}
+
+void interrupt2()
+{
+ osSignalSet(mainThread, 0x2);
+}
+
+int main()
+{
+ pc.baud(115200);
+ pc.printf("Init\n\r");
+
+ // Get the id of the main thread
+ mainThread = Thread::gettid();
+
+ tick1.attach(&interrupt1, 1.0); // setup ticker to call interrupt1 every 1.0 seconds
+ tick2.attach(&interrupt2, 2.0); // setup ticker to call interrupt2 every 1.0 seconds
+
+ while (true) {
+ // If the event mask is set to 0, then any signal will exit the wait.
+ // If nothing happens for 10 seonds, timeout
+ // Internaly the code is doing something like this:
+ // if (signal1 | signal2) then exit wait
+ osEvent v = osSignalWait(0, 10000);
+ pc.printf("Wait1 exit. Status: 0x%x\n",(int) v.status);
+
+ if (v.status == osEventSignal) {
+ pc.printf("Signals Event1 Caught: 0x%x\n",(int) v.value.signals);
+
+ // Tick1 timeout
+ if (v.value.signals & 0x1) {
+ led1 = !led1;
+ pc.printf("Event1 0x1\n");
+ }
+
+ // Tick2 timeout
+ if (v.value.signals & 0x2) {
+ led2 = !led2;
+ pc.printf("Event1 0x2\n");
+ }
+
+ }
+
+ // Use this form to wait for both events
+ // Internaly the code is doing something like this:
+ // if ((signal1 | signal2) & 0x3 == 0x3) then exit wait
+ v = osSignalWait(0x3, 10000);
+ pc.printf("Wait2 exit. Status: 0x%x\n",(int) v.status);
+
+ if (v.status == osEventSignal) {
+ pc.printf("Signals Event2 Caught: 0x%x\n",(int) v.value.signals);
+
+ // Tick1 timeout
+ if (v.value.signals & 0x1) {
+ led1 = !led1;
+ pc.printf("Event2 0x1\n");
+ }
+
+ // Tick2 timeout
+ if (v.value.signals & 0x2) {
+ led2 = !led2;
+ pc.printf("Event2 0x2\n");
+ }
+
+ }
+
+ }
+}
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