Thread: Best way to measure period between pulses? Counters and FPGA
View Single Post
  #5   Spotlight this post!  
Unread 28-01-2013, 01:13
jhersh jhersh is offline
National Instruments
AKA: Joe Hershberger
FRC #2468 (Appreciate)
Team Role: Mentor
  
Join Date: May 2008
Rookie Year: 1997
Location: Austin, TX
Posts: 1,006
jhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond reputejhersh has a reputation beyond repute
Re: Best way to measure period between pulses? Counters and FPGA
Quote:
Originally Posted by Mr. Lim View Post
Well, to answer my own question...

It seems it is possible to directly measure time between transitions with a Counter object by using SemiPeriodMode.

Thanks to Joe Hershberger's post on the FIRST Forums here:
http://forums.usfirst.org/showpost.p...8&postcount=12
That's not quite an accurate interpretation of my post. You can measure the frequency in any of the counter / encoder modes. The point I was trying to make was that the semi-period mode is pretty much useful only for timing.

From reading your application description, you probably want to use Up/Down counter mode, and only specify the "up source". When you read the timer output, it will be reporting the speed based on "method 2" that you described above.

Cheers
-Joe