- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
i want to generate pwm for diffrent %of duty cycle.
I know the formula of dutycycle is
dutycycle=100 x compare value/period.
But this formula is giving wrong results in som ecases.
For example.
i want to generate a dutycycle of 50% ,
then my settings are compare value=1,set period=2ms ,input fequency is 1000HZ .According to the formula it has to give 50% duty cycle.
But in the configuration window it shows the wavesorm of 70% .
so,please help me to resolve the issue
Thanks in advance.
Solved! Go to Solution.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
You wrote
dutycycle=100 x compare value/period.
this is not quite correct
dutycycle=100 x compare value/period value
is better.
So the period value should be set to 19 (giving a period of 20 pulses) the input clock to 10kHz and the compare value to 10.
Always leave some room for adjustings, you could have choosen as well
Period value = 199, input clock 100kHz, compare value = 100.
This settings would allow for a 1% resolution setting of the duty cycle.
Bob
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
You wrote
dutycycle=100 x compare value/period.
this is not quite correct
dutycycle=100 x compare value/period value
is better.
So the period value should be set to 19 (giving a period of 20 pulses) the input clock to 10kHz and the compare value to 10.
Always leave some room for adjustings, you could have choosen as well
Period value = 199, input clock 100kHz, compare value = 100.
This settings would allow for a 1% resolution setting of the duty cycle.
Bob