Help with PWM and duty and integers
Hi all,
I'm having a hard time making a program run correctly for me. I'm trying to achieve the age old RBG LED fade sequence on my own (I have used several existing programs already).
I'm having a problem with my code where the LEDs are not fading - actually they are off most of the time and simply "pop" on for a split second in sequence.
I believe the problem is that I'm send non-integer values to the "duty" variable in PWM - or am I? I'm so confused as to what 10/3 looks like.. is it 3? Is it 3.33333 is it 333? Argh.
Also, is it necessary for the "duty" variable in PWM to be a integer?
Please don't suggest HPWM, I am trying to sharpen my programming skills with this excercize.
My Pic is 16F684 with PicBasicPro
here is the code I'm using:
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DEFINE OSC 8
OSCCON=%01110000 '8 Mhz
CMCON0 = 7
TRISA = %00001000 'set all ports to output
'define ports
green VAR TRISA.0
red VAR TRISA.1
blue VAR TRISA.2
rbgArray var byte[3] ' holds the rgb values in this case the led is rbg
x var byte ' allows PWM to repeat
y var byte ' sets the rgb values
z var byte ' controls speeding up or slowing down state
rainbowVal var word ' the current value to produce rainbow
maxcolors var word ' the number of colors in the rainbow
thirdmax var word
dbthirdmax var word
maxtime var byte ' controlls the minimum speed of the color shifting
time var byte ' number of times to repeat PWM
x = 0
y = 0
z = 1
time = 1
maxtime = 2 ' set the max slow
maxcolors = 300 ' set the rainbow size !must be divisable by 3
thirdmax = maxcolors / 3 ' to simplify equations below
dbthirdmax = 2 * thirdmax ' to simplify equations below
main:
for rainbowval = 1 to maxcolors
gosub rbgrainbow
next
for rainbowval = maxcolors to 1 step - 1
gosub rbgrainbow
next
'this section changes the speed of color change
if (time < maxtime) and (z = 1) then
time = time + 1 'slowing down
else
time = time - 1 'speeding up
endif
if time = maxTime then
z = 2 'when max "slow" is reached, prog switches to speeding up
endif
if time = 1 then
z = 1 'when max "fast" is reached, prog switches to slowing down
endif
goto main
rbgrainbow:
if (rainbowval <= thirdmax) then
rbgarray[0] = ((rainbowval / thirdmax) * 255) 'red ramping up
rbgarray[1] = 0 'green off
rbgarray[2] = ((thirdmax - rainbowval) / thirdmax) * 255 'blue ramping down
endif
if (rainbowval > thirdmax) and (rainbowval <= dbthirdmax) then
rbgarray[0] = ((dbthirdmax - rainbowval) / thirdmax ) * 255 'red ramping down
rbgarray[1] = ((rainbowval - thirdmax) / thirdmax)* 255 'green ramping up
rbgarray[2] = 0 'blue off
endif
if (rainbowval > dbthirdmax) and (rainbowval <= maxcolors) then
rbgarray[0] = 0 'red off
rbgarray[1] = ((maxcolors - rainbowval) / thirdmax) * 255 'green ramping down
rbgarray[2] = ((rainbowval - dbthirdmax) / thirdmax) * 255 'blue ramping up
endif
gosub ledpwm
return
ledPWM:
for x = 1 to time
For y = 0 to 2
Select Case y
Case 0
pwm red, rbgarray[y], 1
case 1
pwm green, rbgarray[y], 1
case 2
pwm blue, rbgarray[y], 1
end select
next
next
return
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can anyone tell me how to make this work! Thanks
