controling a RGB Led

LEDboy

I need some help I've been playing around with the FullDuplexSerialPlus program and a RGB Led. What I'm trying to do is us the FullDuplexSerialPlus as an input for the duty cycle of the RGB.· I would like·to be able to ajust the brightness 0 -255 of the 3 colors in order to make diffrent colors...can someone point me in the right direction. It cant be as hard as I'm making it. hahaha·

StefanL38

Hello,

the FDS+-onject provides a method

  PUB getstr(stringptr)

with this you could receive a string containing a character "R" , "G", "B" for indicating the channel and a value
example: "B128"

and then use the StrToDec-method to change the string "128" into the integernumber 128

the string has to be ZERO-terminated when using FDS+

if you use the extended_FDSerial-object (ExFDS) there is a version where strings can be terminated with a carriage return or
a self defined delimiter

then in in the obex there is a PWM-object

Dedicated pwm generator
with a small demoprogram for that.

attention in the CON-section of the PWM-demo you have to change the

CON _clkmode = xtal1 + pll16x
    _xinfreq = 6_000_000             ' CHECK THIS!!! most parallax boards use  _xinfreq = 5_000_000

best regards

Stefan

MagIO2

On a first glance it looks like "Dedicated pwm generator" is not optimal for driving the LED. Of course for playing with it it's a fast and easy solution. But I'd never use it in a serious case as you have to start 3 COGs, one for each color.
A COG using both counters would not be enough as well. But I believe for this usecase it would be feasible to do the PWM in software. Doing a 16 bit PWM @ some kHz should be doable.