Vignesh:
Some have said that software loops in C are not predictable in terms of delay time.

I want to clarify that this is somewhat misleading to have this stated in this manner. The part that is unpredictable is when you compare the loop times you currently experience with those that are created when you process your c program software delay under conditions of the following types:

1. Using a different version of the compiler to make your program's run time image.


2. Using a compiler from a another vendor.


3. Changing the memory model or optimization level of the compiler tool.


4. Adding adjacent code in the source that somehow changes the optimization at compile time even though the same tool at the same settings were used.


5. Running your code on an different hardware platform.

However.....all those issues aside there there are times when a software delay loop in C is a suitable and justified means to institute a delay in the code execution time. It is of course up to you to decide what is suitable when taking all of the above types of issues into account.

A very effective means to measure the time delay of a C code loop is to use a spare port bit as a singal flag. Set the bit as the time delay routine starts and clear it again after the delay routine is finished. Then use an oscilloscope to observe this resulting pulse on the spare port pin while the program is running. You can very quickly see exactly how long the delay is.

Michael Karas