Ye Cheng / Mbed 2 deprecated cmsis_rtos_demo_signal

cmsis rtos demo

Dependencies:   mbed-rtos mbed

main.cpp@1:8289e2db9449, 2013-01-06 (annotated)

Committer:
cnhzcy14
Date:
Sun Jan 06 15:13:50 2013 +0000
Revision:
1:8289e2db9449
Parent:
0:9a66107976a4 
comments

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cnhzcy14 1:8289e2db9449 1 /******************************************************************************
cnhzcy14 1:8289e2db9449 2 * DESCRIPTION:
cnhzcy14 1:8289e2db9449 3 * Example code for using CMSIS RTOS Signal. The main thread
cnhzcy14 1:8289e2db9449 4 * creates three threads. Two of those threads increment a "count" variable,
cnhzcy14 1:8289e2db9449 5 * while the third thread watches the value of "count". When "count"
cnhzcy14 1:8289e2db9449 6 * reaches a predefined limit, the waiting thread is signaled by one of the
cnhzcy14 1:8289e2db9449 7 * incrementing threads. The waiting thread "awakens" and then modifies
cnhzcy14 1:8289e2db9449 8 * count. The program continues until the incrementing threads reach
cnhzcy14 1:8289e2db9449 9 * TCOUNT. The main program prints the final value of count.
cnhzcy14 1:8289e2db9449 10 * SOURCE: Adapted from example code in "Pthreads Programming", B. Nichols
cnhzcy14 1:8289e2db9449 11 * et al. O'Reilly and Associates.
cnhzcy14 1:8289e2db9449 12 * MODIFICATOR: (Simon) CHENG Ye
cnhzcy14 1:8289e2db9449 13 * LAST REVISED: 06/JAN/2013
cnhzcy14 1:8289e2db9449 14 ******************************************************************************/
cnhzcy14 1:8289e2db9449 15
cnhzcy14 0:9a66107976a4 16 #include "mbed.h"
cnhzcy14 0:9a66107976a4 17 #include "cmsis_os.h"
cnhzcy14 0:9a66107976a4 18
cnhzcy14 0:9a66107976a4 19 #define NUM_THREADS 3
cnhzcy14 0:9a66107976a4 20 #define TCOUNT 10
cnhzcy14 0:9a66107976a4 21 #define COUNT_LIMIT 12
cnhzcy14 0:9a66107976a4 22
cnhzcy14 0:9a66107976a4 23 int count = 0;
cnhzcy14 0:9a66107976a4 24 osMutexId count_mutex;
cnhzcy14 0:9a66107976a4 25 osMutexDef(count_mutex);
cnhzcy14 0:9a66107976a4 26
cnhzcy14 0:9a66107976a4 27 struct thread_data
cnhzcy14 0:9a66107976a4 28 {
cnhzcy14 0:9a66107976a4 29 osThreadId id;
cnhzcy14 0:9a66107976a4 30 long my_id;
cnhzcy14 0:9a66107976a4 31 };
cnhzcy14 0:9a66107976a4 32
cnhzcy14 0:9a66107976a4 33 struct thread_data thread_data_array[NUM_THREADS-1];
cnhzcy14 0:9a66107976a4 34 Serial debug(USBTX, USBRX);
cnhzcy14 0:9a66107976a4 35
cnhzcy14 0:9a66107976a4 36 void inc_count(void const *threadarg)
cnhzcy14 0:9a66107976a4 37 {
cnhzcy14 0:9a66107976a4 38 int i;
cnhzcy14 0:9a66107976a4 39 long my_id;
cnhzcy14 0:9a66107976a4 40 osThreadId id;
cnhzcy14 0:9a66107976a4 41 struct thread_data *my_data;
cnhzcy14 0:9a66107976a4 42 my_data = (struct thread_data *) threadarg;
cnhzcy14 0:9a66107976a4 43 id = my_data->id;
cnhzcy14 0:9a66107976a4 44 my_id = my_data->my_id;
cnhzcy14 0:9a66107976a4 45
cnhzcy14 0:9a66107976a4 46 for (i=0; i < TCOUNT; i++) {
cnhzcy14 0:9a66107976a4 47 osMutexWait(count_mutex, osWaitForever);
cnhzcy14 0:9a66107976a4 48 count++;
cnhzcy14 0:9a66107976a4 49
cnhzcy14 0:9a66107976a4 50 /*
cnhzcy14 1:8289e2db9449 51 * Check the value of count and signal waiting thread when condition is
cnhzcy14 1:8289e2db9449 52 * reached. Note that this occurs while mutex is locked.
cnhzcy14 0:9a66107976a4 53 */
cnhzcy14 1:8289e2db9449 54 if (count == COUNT_LIMIT)
cnhzcy14 1:8289e2db9449 55 {
cnhzcy14 0:9a66107976a4 56 printf("inc_count(): thread %ld, count = %d Threshold reached. ",
cnhzcy14 0:9a66107976a4 57 my_id, count);
cnhzcy14 0:9a66107976a4 58 osSignalSet(id, 0x1);
cnhzcy14 0:9a66107976a4 59 printf("Just sent signal.\n");
cnhzcy14 0:9a66107976a4 60 }
cnhzcy14 0:9a66107976a4 61 printf("inc_count(): thread %ld, count = %d, unlocking mutex\n",
cnhzcy14 0:9a66107976a4 62 my_id, count);
cnhzcy14 0:9a66107976a4 63 osMutexRelease(count_mutex);
cnhzcy14 0:9a66107976a4 64
cnhzcy14 0:9a66107976a4 65 /* Do some work so threads can alternate on mutex lock */
cnhzcy14 0:9a66107976a4 66 osDelay(1000);
cnhzcy14 0:9a66107976a4 67 }
cnhzcy14 0:9a66107976a4 68 id = osThreadGetId();
cnhzcy14 0:9a66107976a4 69 osThreadTerminate(id);
cnhzcy14 0:9a66107976a4 70 }
cnhzcy14 0:9a66107976a4 71
cnhzcy14 0:9a66107976a4 72 void watch_count(void const *t)
cnhzcy14 0:9a66107976a4 73 {
cnhzcy14 0:9a66107976a4 74 osThreadId id;
cnhzcy14 0:9a66107976a4 75 long my_id = (long)t;
cnhzcy14 0:9a66107976a4 76
cnhzcy14 0:9a66107976a4 77 printf("Starting watch_count(): thread %ld\n", my_id);
cnhzcy14 0:9a66107976a4 78
cnhzcy14 1:8289e2db9449 79 /*
cnhzcy14 1:8289e2db9449 80 * Lock mutex and wait for signal. Note that the pthread_cond_wait routine
cnhzcy14 1:8289e2db9449 81 * will automatically and atomically unlock mutex while it waits.
cnhzcy14 1:8289e2db9449 82 * Also, note that if COUNT_LIMIT is reached before this routine is run by
cnhzcy14 1:8289e2db9449 83 * the waiting thread, the loop will be skipped to prevent pthread_cond_wait
cnhzcy14 1:8289e2db9449 84 * from never returning.
cnhzcy14 1:8289e2db9449 85 */
cnhzcy14 1:8289e2db9449 86 osMutexWait(count_mutex, osWaitForever);
cnhzcy14 1:8289e2db9449 87 while (count < COUNT_LIMIT)
cnhzcy14 1:8289e2db9449 88 {
cnhzcy14 1:8289e2db9449 89 osMutexRelease(count_mutex);
cnhzcy14 0:9a66107976a4 90 printf("watch_count(): thread %ld Count= %d. Going into wait...\n", my_id,count);
cnhzcy14 0:9a66107976a4 91 osSignalWait(0x1, osWaitForever);
cnhzcy14 1:8289e2db9449 92 osMutexWait(count_mutex, osWaitForever);
cnhzcy14 0:9a66107976a4 93 printf("watch_count(): thread %ld Condition signal received. Count= %d\n", my_id,count);
cnhzcy14 0:9a66107976a4 94 printf("watch_count(): thread %ld Updating the value of count...\n", my_id);
cnhzcy14 0:9a66107976a4 95 count += 125;
cnhzcy14 0:9a66107976a4 96 printf("watch_count(): thread %ld count now = %d.\n", my_id, count);
cnhzcy14 1:8289e2db9449 97 osMutexRelease(count_mutex);
cnhzcy14 0:9a66107976a4 98 }
cnhzcy14 0:9a66107976a4 99 printf("watch_count(): thread %ld Unlocking mutex.\n", my_id);
cnhzcy14 0:9a66107976a4 100 //osMutexRelease(count_mutex);
cnhzcy14 0:9a66107976a4 101 id = osThreadGetId();
cnhzcy14 0:9a66107976a4 102 osThreadTerminate(id);
cnhzcy14 0:9a66107976a4 103 }
cnhzcy14 0:9a66107976a4 104
cnhzcy14 0:9a66107976a4 105 void th0(void const *argument) {watch_count(argument);}
cnhzcy14 0:9a66107976a4 106 osThreadDef(th0, osPriorityNormal, DEFAULT_STACK_SIZE);
cnhzcy14 0:9a66107976a4 107
cnhzcy14 0:9a66107976a4 108 void th1(void const *argument) {inc_count(argument);}
cnhzcy14 0:9a66107976a4 109 osThreadDef(th1, osPriorityNormal, DEFAULT_STACK_SIZE);
cnhzcy14 0:9a66107976a4 110
cnhzcy14 0:9a66107976a4 111 void th2(void const *argument) {inc_count(argument);}
cnhzcy14 0:9a66107976a4 112 osThreadDef(th2, osPriorityNormal, DEFAULT_STACK_SIZE);
cnhzcy14 0:9a66107976a4 113
cnhzcy14 0:9a66107976a4 114 int main(int argc, char *argv[])
cnhzcy14 0:9a66107976a4 115 {
cnhzcy14 0:9a66107976a4 116 debug.baud(57600);
cnhzcy14 0:9a66107976a4 117 long t1=1, t2=2, t3=3;
cnhzcy14 0:9a66107976a4 118 osThreadId id;
cnhzcy14 0:9a66107976a4 119
cnhzcy14 1:8289e2db9449 120 /* Initialize mutex objects */
cnhzcy14 0:9a66107976a4 121 count_mutex = osMutexCreate(osMutex(count_mutex));
cnhzcy14 0:9a66107976a4 122
cnhzcy14 0:9a66107976a4 123 id = osThreadCreate(osThread(th0), (void *)t1);
cnhzcy14 0:9a66107976a4 124 thread_data_array[0].id = id;
cnhzcy14 0:9a66107976a4 125 thread_data_array[0].my_id = t2;
cnhzcy14 1:8289e2db9449 126 thread_data_array[1].id = id;
cnhzcy14 0:9a66107976a4 127 thread_data_array[1].my_id = t3;
cnhzcy14 0:9a66107976a4 128 osThreadCreate(osThread(th1), (void *)&thread_data_array[0]);
cnhzcy14 0:9a66107976a4 129 osThreadCreate(osThread(th2), (void *)&thread_data_array[1]);
cnhzcy14 0:9a66107976a4 130
cnhzcy14 0:9a66107976a4 131 printf ("Main(): Waited and joined with %d threads. Final value of count = %d. Done.\n",
cnhzcy14 0:9a66107976a4 132 NUM_THREADS, count);
cnhzcy14 1:8289e2db9449 133 }