Felipe Neves / Mbed OS TEN_mbedos_events

TEN MBED OS Course events lab

main.cpp@0:4303da3c75bf, 2017-01-29 (annotated)

Committer:
uLipe
Date:
Sun Jan 29 20:40:45 2017 +0000
Revision:
0:4303da3c75bf
first

Who changed what in which revision?

UserRevisionLine numberNew contents of line
uLipe 0:4303da3c75bf 1 /**
uLipe 0:4303da3c75bf 2 * @brief first event control program with MBED OS
uLipe 0:4303da3c75bf 3 */
uLipe 0:4303da3c75bf 4 #include "mbed.h"
uLipe 0:4303da3c75bf 5 #include "rtos.h"
uLipe 0:4303da3c75bf 6 #include "mbed_events.h"
uLipe 0:4303da3c75bf 7
uLipe 0:4303da3c75bf 8 /* declares threads for this demo: */
uLipe 0:4303da3c75bf 9 const size_t a_stk_size = 1024;
uLipe 0:4303da3c75bf 10 uint8_t a_stk[a_stk_size];
uLipe 0:4303da3c75bf 11 Thread a_thread(osPriorityNormal, a_stk_size, &a_stk[0]);
uLipe 0:4303da3c75bf 12
uLipe 0:4303da3c75bf 13 /* thread b is used as event loop thread*/
uLipe 0:4303da3c75bf 14 Thread b_thread;
uLipe 0:4303da3c75bf 15
uLipe 0:4303da3c75bf 16 /* queue used to handle events */
uLipe 0:4303da3c75bf 17 EventQueue ev_queue(32 * EVENTS_EVENT_SIZE);
uLipe 0:4303da3c75bf 18
uLipe 0:4303da3c75bf 19 /* reserve the debbuger uart to shell interface */
uLipe 0:4303da3c75bf 20 Serial pc_serial(USBTX,USBRX);
uLipe 0:4303da3c75bf 21
uLipe 0:4303da3c75bf 22 /* allocate HW for button with interrupt */
uLipe 0:4303da3c75bf 23 InterruptIn sw(SW2);
uLipe 0:4303da3c75bf 24
uLipe 0:4303da3c75bf 25
uLipe 0:4303da3c75bf 26 /**
uLipe 0:4303da3c75bf 27 * @brief thread a function
uLipe 0:4303da3c75bf 28 */
uLipe 0:4303da3c75bf 29 static void thread_a(void)
uLipe 0:4303da3c75bf 30 {
uLipe 0:4303da3c75bf 31 int pressed = 0;
uLipe 0:4303da3c75bf 32 for(;;) {
uLipe 0:4303da3c75bf 33 /* halt thread until a signal is received */
uLipe 0:4303da3c75bf 34 a_thread.signal_wait(1, osWaitForever);
uLipe 0:4303da3c75bf 35 pressed++;
uLipe 0:4303da3c75bf 36 pc_serial.printf("## button press woke up this thread, noof presses: %d !##\n\r", pressed);
uLipe 0:4303da3c75bf 37 pc_serial.printf("## now this thread will wait for a new press !##\n\r");
uLipe 0:4303da3c75bf 38 }
uLipe 0:4303da3c75bf 39 }
uLipe 0:4303da3c75bf 40
uLipe 0:4303da3c75bf 41
uLipe 0:4303da3c75bf 42 /**
uLipe 0:4303da3c75bf 43 * @brief event callback called from thread context
uLipe 0:4303da3c75bf 44 */
uLipe 0:4303da3c75bf 45 static void button_callback(void)
uLipe 0:4303da3c75bf 46 {
uLipe 0:4303da3c75bf 47 /* button callback is used to assert a signal,
uLipe 0:4303da3c75bf 48 * this is the advantage of event loop, signals are not allowed
uLipe 0:4303da3c75bf 49 * to use in ISR, but this callback is executed from thread
uLipe 0:4303da3c75bf 50 * context
uLipe 0:4303da3c75bf 51 */
uLipe 0:4303da3c75bf 52 a_thread.signal_set(1);
uLipe 0:4303da3c75bf 53 }
uLipe 0:4303da3c75bf 54
uLipe 0:4303da3c75bf 55
uLipe 0:4303da3c75bf 56 /**
uLipe 0:4303da3c75bf 57 * @brief main application loop
uLipe 0:4303da3c75bf 58 */
uLipe 0:4303da3c75bf 59 int main(void)
uLipe 0:4303da3c75bf 60 {
uLipe 0:4303da3c75bf 61 pc_serial.baud(115200);
uLipe 0:4303da3c75bf 62 a_thread.start(thread_a);
uLipe 0:4303da3c75bf 63 b_thread.start(callback(&ev_queue, &EventQueue::dispatch_forever));
uLipe 0:4303da3c75bf 64 sw.rise(ev_queue.event(button_callback));
uLipe 0:4303da3c75bf 65 return 0;
uLipe 0:4303da3c75bf 66 }