Timer Capture Tiva TM4C123GXL

Hi, 

See this thread for a similar request or search the forum first:

http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/p/327659/1141047.aspx#1141047

Petrei

Hi Petrei,

I've looked through the thread but I don't really understand the code. I've tried putting the code in to find the number of cycles but the number I get is 0.

Hi,

There is a hidden register inside micro, cycle counter, which allows to count the number of elapsed cycles between a start command and a stop one, if the cycle counter was enabled. The cycle counter is 32 bits long, so at 80 MHz maximum time (before overflow) is around 53 seconds.

Read all the posts in that thread, since some added declarations were revealed after the post with the code in blue fonts (depends on what you do - when I posted first i had already included some of the missing declarations). Maybe you are in the same situation.

And depending on your real case, the procedure is: start command, set x=0, do another thing until x=2000 and emit stop command. Take into account what was done during x=0 and x=2000 if you want to be extremely precise.

If you "measure" long time intervals and no need for accuracy, then an alternative is to start/stop a timer. 

Petrei

Hi Petrei,

Sorry for the late response. If I were to use a timer, how should I configure the Timer and what should I put in the Interrupt Handler?

Hi,

You may configure the timer as 16-bit or 32-bit periodic timer and in this case the resolution of measurement is the system clock period. For 16-bit periodic timer, it will overflow soon enough, so if your expected time intervals are more than overflow time, then you will need to configure the interrupt to count also the number of overflows. 

You may play with the timer as you wish - even to use the built-in prescaler. 

Petrei