View Single Post
  #1   Spotlight this post!  
Unread 16-01-2015, 14:14
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: Using the TI LaunchPad from your KoP

Quote:
Originally Posted by ayeckley View Post
We've determined that the likely cause is due to use of a polled-input approach. The default code for the Launchpad-FRC polls at 10ms, but at a realistic knob-turning rate the rising edges of the ticks from Phase A can occur at ~5ms apart. Anyone see a problem there? By switching to an interrupt-based approach and a reasonably tightly-coded ISR we expect to resolve the issue [hopefully] without screwing up the interrupts used in the serial communications process.
If you only decode in 1X mode (rising edge on A only) then you have 1/4 the interrupts to process. Seems pretty doable. Polled input had better have plenty of headroom to be reliable, but you've already discovered that.
Reply With Quote