RTX筆記5 - 事件標志組 event flags

　　事件標志組用於線程間同步，每一個事件標志組都有31個時間標志位（除最高位）。

 　　osEventFlagsId_t osEventFlagsNew (const osEventFlagsAttr_t *attr)：

　　　　創建一個事件標志組，返回時間標志ID 或者 NULL。不可在中斷中調用。

osEventFlagsAttr_t Data Fields
const char *	name	name of the event flags Pointer to a constant string with a human readable name (displayed during debugging) of the event flag object. Default: NULL no name specified.
uint32_t	attr_bits	attribute bits Reserved for future use (must be set to '0' for future compatibility).
void *	cb_mem	memory for control block Pointer to a memory for the event flag control block object. Refer to Static Object Memory for more information. Default: NULL to use Automatic Dynamic Allocation for the event flag control block.
uint32_t	cb_size	size of provided memory for control block The size (in bytes) of memory block passed with cb_mem. For RTX, the minimum value is defined with osRtxEventFlagsCbSize (higher values are permitted). Default: 0 as the default is no memory provided with cb_mem.

　　uint32_t osEventFlagsSet (osEventFlagsId_t ef_id, uint32_t flags)

　　　　設置事件標志組相應flags位。返回設置后標志或者錯誤碼。最高位不可設置。可在中斷中調用。

　　uint32_t osEventFlagsWait (osEventFlagsId_t ef_id, uint32_t flags, uint32_t options, uint32_t timeout)

　　　　等待時間標志組相應flags位被設置，默認情況下，該函數返回時，會將相應的等待標志位清零，其他位保持不變。可在中斷中調用。

　　　　

Option
osFlagsWaitAny	Wait for any flag (default).
osFlagsWaitAll	Wait for all flags.
osFlagsNoClear	Do not clear flags which have been specified to wait for.

Note：

函數 osEventFlagsSet, osEventFlagsClear, osEventFlagsGet, and osEventFlagsWait 可以在中斷中調用。

osEventFlagsId_t evt;

void
testEventFlags(void)
{
    evt = osEventFlagsNew(NULL);
    osThreadNew(_ledThread, NULL, NULL); // Create application led thread
    osThreadNew(_thread2, NULL, NULL); // Create application segment led thread
}

static void
_ledThread(void *argument)
{
    (void)argument;
    uint32_t flags;
    
    for(;;) {
        flags = osEventFlagsWait(evt, 0x00000001, osFlagsWaitAny, osWaitForever);
        menuShow(&seg_led, flags, 0);
        
        flags = osEventFlagsWait(evt, 0x00000002, osFlagsWaitAny, osWaitForever);
        menuShow(&seg_led, flags, 0);
        
        flags = osEventFlagsWait(evt, 0x0000000C, osFlagsWaitAll | osFlagsNoClear, osWaitForever);
        flags = osEventFlagsGet(evt);
        menuShow(&seg_led, flags, 0);
        osEventFlagsClear (evt, 0x0000000C);
        
        flags = osEventFlagsWait(evt, 0x00000007, osFlagsWaitAll, osWaitForever);
        menuShow(&seg_led, flags, 0);
    }
}

static void
_thread2(void *argument)
{
    (void)argument;
    for(;;) {
        osEventFlagsSet(evt, 0x00000001);
        osDelay(1000);
        
        osEventFlagsSet(evt, 0x00000002);
        osDelay(1000);
        
        osEventFlagsSet(evt, 0x0000000C);
        osDelay(1000);
        
        osEventFlagsSet(evt, 0x00000007);
        osDelay(1000);
    }
}