Slowing Down RGB PWM Routine

I have an RGB sequence which works fairly well, but very quickly. Is there a way of slowing down the routine. I have tried altering the PWM duty, but this just causes the LEDs to flicker. Also the Pause command produces the same flickering results.

I would like the transition of clours to be a lot slower.

This is part of a bigger routine, but i would like to get this part right.

Any ideas from anyone?

Many thanks,

Steve

Quote:

---

TRISB = 0

Red VAR PORTB.1 ' All LEDs
Green VAR PORTB.2 ' Connected between
Blue VAR PORTB.3 ' RC pins and ground

rbgArray var byte[3] ' holds the rgb values in this case the led is rbg
x var byte
y var byte
adcVar var byte
rbg var byte ' which value we are changing in the rbg array
rainbowVal var byte ' the current value to produce rainbow
Delta var byte ' find the size of each section in the 6stage rainbow
Section var byte ' which section it is in

maxValue con 255 'the maximum input value for generating rainbow

delta = maxValue/6

y = 0

main:
for rainbowval = 0 to 255
gosub rbgrainbow
next
for rainbowval= 255 to 0 step - 1
gosub rbgrainbow
next
goto main


rbgrainbow:
for rbg = 0 to 2
section = ((rainbowval + ((rbg * 2)*delta))/ delta) // 6 ' this gives what section it is in

select case section
case 0
rbgarray[rbg] = (rainbowval // delta)*6 'this is how far it has gone in its section
case 1
rbgarray[rbg] = 255
case 2
rbgarray[rbg] = 255
case 3
rbgarray[rbg] = 255 - ((rainbowval //delta)*6)
case 4
rbgarray[rbg] = 0
case 5
rbgarray[rbg] = 0
case 6 'this one is for pics bad math
rbgarray[rbg] = 0
end select
next

gosub ledpwm

return

ledPWM:
For y = 0 to 2
Select Case y
Case 0
pwm red, rbgarray[y], 1
case 1
pwm blue, rbgarray[y], 1
case 2
pwm green, rbgarray[y], 1
end select
next
return

---

Perhaps you could call your "ledPWM" routine more than once. That should keep the LEDs happy and take longer time.

OK, i think i know what you mean, but being new, how do i do that in the code i have. Would you mind giving me an example using my code?

I'm guessing it will use a loop where i call that routine, say ten times and then jump to the next sequences etc.

Many thanks.

Steve

That is not so hard let me help ya;

Code:

---



main:

for rainbowval = 0 to 255

for a = 1 to 100
gosub rbgrainbow
next a
next rainbowval
for rainbowval= 255 to 0 step - 1
for a = 1 to 100
gosub rbgrainbow
next a
next rainbowval

goto main

---

of course you have to adjust the value's and you have to create the variable "A" (if your gone use high value's create a word size variable)

Edit: you could also let a timer run in the background that keeps sending the pwm signals and change the value's in the mainloop

Hi Tissy,

Since the software PWM command only works while that statement is active. It's going to be difficult to get the LED's to work the way you're wanting.

Take a look at this link
Multiple Slow speed Software PWM

This will allow you to have all 3 PWM's running in the background at the same time. Then you can just cycle thru the PWM levels as needed without worrying about the timing.


HTH,
   Darrel

Exactly what i meant ......

FOR X = 1 to 10
GOSUB ledpwm
NEXT