I don't understand how waitcnt works

sheonbanks

I'm reading the ConstantBlinkRate.spin code. It states"
"For a 1 Hz on/off signal, replace both instances of clkfrq/2 with 2_500_000"

which would result in:
waitcnt(2_500_00 + CNT)

If the system clock is 80mHz where does the 1 Hz come from. I don't understand the correlation. Mathematically, given then various terms, I don't understand how you have a number(such as 2_500_000) in mHz producing a 1 Hz blink count?

BTX

I have not near me that code, but......

What about the:·· _clkmode·····and the··· _xinfreq·······values ?, in the CON block of the code.....

Why do you afirm that the system clock is 80 Mhz ?? maybe it is only 5Mhz.

Look close at the _clkmode·and the _xinfreq please.

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Regards.

Alberto.

sheonbanks

the code is using pll16x

deSilva

Tutorial said...

Timing with clkfreq vs. Timing with Constants
Let’s say that a constant value is used in place of clkfreq to make the program work a certain way at
one particular system clock frequency. What happens when the Propeller system clock frequency
changes?
* Save a copy of the ConstantBlinkRate object as BlinkRatesWithConstants.spin.
* Make sure the PLL multiplier is set to pll1x so that the system clock runs at 5 MHz.
* For a 1 Hz on/off signal, replace both instances of clkfrq/2 with 2_500_000.
* Load the object into the Propeller chip’s RAM and verify that the LED blinks at 1 Hz.
* Next, change the PLL multiplier to pll2x. Load the modified object into

rjo_

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Rich