Can't get correct pwm speed going on PIC12f1501

[chad]

I am trying to get a 13hz pwm out of the 1501 Cant' seem to get it going at the right freq.
I set my properties in the component and enabled it. I am using channel 4 that should be RA2. I can get a 1k out but it doesn't seem to let me go below that? The display in the component looks right?

Any Ideas?

Chad

[QMESAR]

To add what leigh said as PWM possible minimum PWM frequency is directly related to OSC frequency . another option is to use a lower OSC speed,

[LeighM]

Sorry, I deleted my previous post because I realised that it should be possible to get a PWM in that range when the Int Osc is down at 31KHz,
which I now guess you are doing based on another post.
What is your actual result on hardware?

[chad]

Hi Leigh,

Actually I am running at 16mhz. I was hoping that I could just set the pwn down low and let the hardware take care of blinking the led while the program did other stuff. I guess I could get creative with a timer and counters or just do it with delays..

Thanks,
Chad

[LeighM]

Ah, right, so might deleted post applies
And as QMESAR post, the PWM max prescaler is divide by 16, and with an 8 bit counter you cannot get below that 1K.
Yes, you could consider a timer interrupt and software based counter to generate your lower frequency

[chad]

Gotcha, I did find something else strange. Just a simple delay loop about every second I get a glitch in the output.
You can see it on the scope trace.
And this is my program.
Any Ideas?

DS1Z_QuickPrint1.png

(39.64 KiB) Downloaded 485 times

flow error glitch.jpg (23.75 KiB) Viewed 3456 times

Chad

[LeighM]

Looks like it's resetting, check watchdog timer setting

[chad]

I turned it off and it does the same thing. Power is stable and good. Totally disconnected the programmer and it still does it.
Hmmm

[chad]

I think I found it. It was the brown out detection. If I disable it it doesn't reset. Very strange.

Chad