Time measurements for function in microcontroller

Question

I am using two microcontrollers for a project, I want to measure execution time for some code with the help of internal timer of both microcontrollers. But One microcontroller's timer count till 32 bit value and second microcontroller's timer can count till 16bit value then it restart. I know that execution time of code is more than 16 bit value. could you suggest me any solution for this problem. (Turning ON and OFF GPIO pin doesn't provide useful results)

Answer 1

You should be able to measure execution time using either type of timer, assuming that execution time is less than days or hours. The real problem is how to configure the timer to meet your needs. How you configure the timer will control the precision or granularity of the measurement, as well as the maximum interval that can be measured.

The general approach will be thus:

1. Identify required precision and estimate the longest interval to be measured
2. Given the precision, determine the timer clock prescaler or divider that will meet your precision requirements. For example, if the clock speed is 50 MHz, and you need microsecond precision, then select a prescaler such that (Prescaler) / (Clock speed) ~ 1 microsecond. A spreadsheet helps with this. For this case, a divider value of 64 gives us about 1.28 microseconds per timer increment.
3. Determine if your timer register is large enough. For a 16-bit timer, you can measure (1.28 microseconds) * (2^16 - 1) = 0.084 seconds, or about a tenth of a second. If the thing you are measuring takes longer than this, you will need to rethink your precision requirements.

You should by now have identified the key parameters to configuring the timer, keeping in mind the limitations. If you update your answer with more specifics, such as the microcontrollers you plan to use and what you're trying to measure, I can be more specific.