easy pwm on any pin or pins with multiple freq's

[brandonb]

i made a post in v5 with a simular topic, this one is slightly different in the way it operates and is easy to manipulate... the way it works with 1% accuracy mode
- the tmr2 macro increases a count everytime its accessed, the count starts at zero and counts up to 100, when count = 100 the count is returned to zero, what i did is turned the output on at count=0 and turned output off when the pwm variable = count,
this gives you a 0-100% dutycycle, all examples are running at 1000hz with 32Mhz osc but have different tmr2 frequencies
- in 1% resolution the frequency of the pwm is determined by tmr2 frequency / 100
- by modifying the tmr2 frequency you can hit many frequencys
- this makes it possible to use pwms on pins that do not have ccp so a board that doesn't give you access to the ccps pins thats not a problem when using something like this project
- you can use as many pwms as you want, and use any i/o pins you want
- in 1% fcf martins code ((adc*100)/255) rescales adc to 0-100, this goes directly to the pwm variable and you can print to the display those numbers as pwm% as its the same
- in other variations 2%,5%,10%,25% to print the number in the lcd macro i use code pwm* XX to put corrent number on display for pwm%

*** the pwm mentioned above and as in first fcf has a resolution of 1% per pwm increase, but you dont have to run 1% you can drop the resolution to anything you want by modifying this line of code in the tmr2 isr

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if(count==100){count=0}

to other values, common are listed below, but to maintain the same frequency you will have to change the tmr2 frequency as in martins post http://www.matrixmultimedia.com/mmforum ... 26&t=10827

1% --> 100
2% --> 50
5% --> 20
10% --> 10
25% --> 4

- all simplified flowcharts below have 1000hz as output frequency notice tmr2 settings are different
- for example if you want to set pwm frequency to 620hz with 5% resolution is 620*20= 12,400
use tmr2 calculator in seperate post (revised fcf) http://www.matrixmultimedia.com/mmforum ... 580#p42633 to find the settings for 12,400 hz, the closest frequency is 12,403 which has the prescaler,postscaler,rollover values of ( 1 - 15 - 43 ) @32Mhz osc , then since 5/100 is 20counts set your tmr2 macro decision to

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if(count==20({count=0}

print to lcd will have to be modified as well

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printNumber(pwm*5)

sorry for my sudo arduino like code but hopefully get the idea



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[brandonb]

this is a picture of how it works visually with the count variable in the tmr2 isr and the pwm variable which gives you the pwm dutycycle.... output goes high at count=0 output goes low at count=pwm.... if pwm variable is 72 then when count=0 output would go high, when count=72 output would go low until count rolls over from 100 and goes back to zero then output would be back on again since count is now zero again