Hi,
ATTiny85 has 3 PWM capable pins, all addressable from inside the IDE. Here's the pin declarations from a sketch I used for a halloween decoration that responded with RGB lighting effects to audio from a Wave Sheild on a Uno (ATTiny was mounted on a shield).
// note these LED pins are ATtiny locations
const int redPin = 1; // IC leg 6 (PB1), output to red channel
const int greenPin = 0; // IC leg 5 (PB0), output to green channel
const int bluePin = 4; // IC leg 3 (PB4), output to blue channel
const int audioPin = 3; // IC leg 2 (PB3), audio level from wave shield
const int activePin = 2; // IC leg 7 (PB2), activation trigger from Arduino
While strictly speaking ATTiny85 leg 2 (D3/PB3) is also capable of PWM, internally it shares the same timer used on leg 3.
Alternatively, you can create PWM effects in software. Something like this will allow you to fade 5 LEDs or other PWM activities where accuracy isn't probably so important (likely you could do something on leg 1 which is D5 also, but I typically try to avoid reusing the reset pin):
void softwarePWM(int PWMfreq, int outputPin, int PWMdelay){
//PWM on
digitalWrite(outputPin,HIGH);
delayMicroseconds(PWMdelay*PWMfreq);
//PWM off
digitalWrite(outputPin,LOW);
delayMicroseconds(PWMdelay*(255-PWMfreq));
} //softwarePWM
Call that function repeatedly on each leg you need to PWM and you have something that (at least for fading LEDs) is perfectly useful. I also used the Arduino-Tiny cores for these.
Cheers ! Geoff
