BUG PWM

[Osta]

Incorrectly generates the PWM frequency!
If you initialize the initialization, then everything is correct!

[medelec35]

Hi Osta,
I have not got 8MHz crystal so using internal oscillator.
PWM frequency looks correct to me.
One thing I had to do first was disable PLL as you have got clock speed set to 8MHz, yet PLL enabled will make chip run at 8x4 = 32MHz.
So there is a mismatch.
What PWM frequency are you measuring and expecting?
What clock speed are you expecting hardware to run at (8 or 32MHz)?


Martin

[Osta]

Hi, Martin!
All right!
It's not about PLL ...
I need PLL.
If the PWM initialization macro is put after the PWM settings, then everything will change and the PWM frequency will be incorrect!

The same project but with the initialization

[Benj]

Hello,

If you're using the PLL then you need to change your clock speed setting to 32000000 in the project options. The properties for the PWM component should then show you what frequencies to expect.

[medelec35]

Hi Osta,

I need PLL.

In that case you must first go to Build, Project Options then General options tab.
Change Clock speed from

Code: Select all

8000000

to

Code: Select all

 32000000

You are also best having Enable as first component to be accessed.
You also don't require change period if you just have a single fixed PWM frequency.
Just set correct frequency within PWM properties as at least you will know what the frequency should be.
Much better than change period.

Martin


Edit: posts crossed so information could be repeated.

[Osta]

Thank you !!
I'm going to try now.

[Osta]

It works the same way ...
From the permutation of the macro, the PWM frequency changes

[medelec35]

I have just tried using internal osc:

PWM setup frequency.png

(42.59 KiB) Downloaded 4146 times

loaded 16F1824 with compiled hex.
PWM from pin C5:

PWM Waveform.png

(102.68 KiB) Downloaded 4146 times

As hardware agrees with PWM settings within Flowcode, I can't tell what the issue is?

If you can measure frequency, can you set

Code: Select all

Clock out enable

to enabled, within configuration settings.
Then measure frequency on pin A3.
You should measure 32/4 8MHz even though clock is running at 32 MHz.

Martin

[Osta]

Hi, Martin !
I'm not talking about setting up.
And about the compilation ....
Here is my example.

[Benj]

Hello,

The PWM Enable component macro calls the Change Period for you using the values in the component properties.

If you want to use values other than those specified in the properties then you need to call the Change Period macro again after enabling the PWM.

[Osta]

Hello Benj!
I thought that the linker has priorities,
Thank you for the clarification.
Thank you Osta.