12.8kHz SQUARE WAVE.

[Tony Brown]

Hi All,

Is it possible to generate a 12.8Khz square wave using a 12f615?

I have tried using TMR2 and got to 7Khz (ish) but the square wave wasnt very square.

Regards

Tony

[medelec35]

Hi Tony,
There are two ways I can think of.
Assuming using internal osc set to 8MHz

1) Add PWM component (don't forget enable).
In PWM properties, Set Prescaler to 1 and Period to 155.
Add SetDutyCycle and use 78 for duty.
That should give a square wave of 12.8205 KHz

Or

2) Add Timer2 interrupt
Set Prescaler and postscaler at 1:1
Set Rollover value to 78
This will give an interrupt frequency of 25.641KHz
Add a Bool variable e.g called toggle.
within interrupt macro, add a calculation box with

Code: Select all

Toggle=!Toggle

Then just set an output using the Toggle variable
That will divide 25.641KHz by 2 with equal time periods.= 12.8205 KHz square wave.

If you get stuck then post a flowchart and I will help you further.

Martin

[Tony Brown]

Thanks Martin, I'll try it over the weekend and update you. When you say "set an output using the toggle variable" what exactly do you mean?

Many thanks

Tony

[Tony Brown]

Hi Martin,

I tried the timer2 method and it worked brilliantly.

Thanks for your help

Regards

Tony

[medelec35]

Hi Tony,
Your welcome.
Glad it works well for you.
Thanks for letting us know.

Martin