Call:      BlockWave(unsigned long Time,int TimerNo) 

Input:    Time in mS, TimerNo 
Output:  boolean 

When calling this function the first time and TimerNo is not known in the timer structure, a new timer structure will be added to the timer chain. When the defined time is expired, the function returns  true (the first time), when the BlockWave expires again the returned boolean is inverted.  Every time the timer expires the returned boolean will be inverted again; block wave with a cycle time of 2 times Time. The timer can be cancelled by the CancelTimer function.

if (BlockWave(2000,TimISR)) Activate (“Buzzer”);