Timing Quirk

lockadoc

I made a small method to light some leds for an amount of time after a button push than they turn off.
the quirk is that when I change the variableto a larger number the on time goes down instead of up.

I can come up with the number I need for the two different delays I want.But would like to know the why of quirk

Bill S

JonnyMac

At some point you're going to roll-over the limit of a 32-bit value and your delays will get smaller. You can save yourself a lot of grief by using a standard timing unit. If you ever used a BASIC Stamp then you're accustomed to PAUSE -- here's how to duplicate that in your programs.

First, create a constant for one millisecond:

con
  MS_001 = 80_000_000 / 1_000

This assumes that you have an 80MHz system (typical). Next create a simple public method:

pub pause(ms) | t

  t := cnt
  repeat ms
    waitcnt(t += MS_001)

BAM! You're done, and no more guessing or calculating values for waitcnt. If you want to wait 0.1 seconds, you use pause(100). Want to wait 2.5 seconds, use pause(2_500). Honestly, it doesn't get much easier than that, and your programs will be much easier to follow.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Jon McPhalen
Hollywood, CA

Post Edited (JonnyMac) : 1/19/2010 1:54:33 AM GMT

Rayman

I'm tired, but doesn't that code show 1 second waits?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
My Prop Info&Apps: ·http://www.rayslogic.com/propeller/propeller.htm

JonnyMac

I'm tired, too -- you're right and I fixed the listing. Thanks for the catch, Ray.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Jon McPhalen
Hollywood, CA

AJM

Phew, I thought I was going to have to start re-learning everything.

Nice code snippet