RGb LED Controller

[wcavanagh]

I wonder if someone can help a poor man. I want to colour cycle a RGB LED smoothly through thounds of colours, it will be used to light up a lod etched in glass, so random colours would be great. I have been told PWM is what i need, I have a PICKit1 and a PicstarPlus programmer from Microchip. I am very new to this and just dont know where to start, I have some PIC12F675 Chips. Anyone recomend anything? PLEASE.......

 

[Rescyou]

Questions

What language are you programming in and what speed are you going to run the 675 at?

Resc.

 

[wcavanagh]

Going to use ASM as that seems to be all i can do with MPLAB, going to use the internal 4Meg clock

 

[Rescyou]

Info

4mhz will work for 3-channels ok if you use the correct methods for pwm, as for ASM I can't help you on that.

Resc.

 

[Nigel Goodwin]

Re: Info

4mhz will work for 3-channels ok if you use the correct methods for pwm, as for ASM I can't help you on that.

Resc.

If he's got the PICKit1 (as he said), it comes with a Lite version of a C compiler - if that helps?.

 

[TheAnimus]

the best way would be to use a TMR0 interupt, then devide it down depending on what value you should have in a file register for each LED.

The TMR0 registrer at 4mhz u might want to use as a global biasing, at the end of the ISR add a value to the TMR0 register.

Thats a pritty rough outline, but it should work fine, you might find a lot of tweaking is needed to get nice linear values (odds are PWM won't provide a smooth change of light intensity with standard linear values)