attiny85 pwm with timer1

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1

I recently started to study attiny datasheet. I need two pwm output for my projects (mainly SPMS with synchronous rectification) and I found out that analogWrite function is no longer enough. To be more precise, I need two pwm (inverted or not) with dead times inserted. After studying the datasheet, in order to get two pwm signals, non-inverted, with variable duty cycle according to the set voltage from a potentiometer, I wrote the following code, which did not work properly:

#define pwm_pin 1
#define pwm_pin_pr 4
#define pot_pin A1

int potinputval;

void setup()
{
pinMode(pwm_pin,OUTPUT);
pinMode(pwm_pin_pr,OUTPUT);
pinMode(pot_pin,INPUT);
TCCR1 = 1<<PWM1A | 1<<COM1A1 | 0<<COM1A0 | 0<<CS13 | 0<<CS12 | 1<<CS11 | 0<<CS10 | 1<<CTC1;
GTCCR = 1<<PWM1B | 1<<COM1B1 | 0<<COM1B0;
OCR1C = 127;
DTPS1 = 0<<DTPS11 | 1<<DTPS10;
DT1B = 1<<DT1BH3 | 1<<DT1BH2 | 1<<DT1BH1 | 1<<DT1BH0;
}

void loop()
{
potinputval=analogRead(pot_pin);
potinputval=map(potinputval,1023,0,127,0);
OCR1A=potinputval;
OCR1B=potinputval;
}

But what I actually get is a set of two identical pwm signals, which are quite shaky.
I added some photos of what my scope is showing.
Please add detailed answers if it is possible. I am new in Arduino and electronics.
Many thanks in advance.

IMG_20170308_141553.gif
IMG_20170308_141553.gif1200×673 342 KB

IMG_20170308_141615.gif
IMG_20170308_141615.gif1200×673 321 KB

2
  1. I would like to suggest you strongly that you play around with ArduinoUNO and practice the use of
  • analogWrite()* function to generate PWM signals at the Dpin connectors of the ArduinoUNO Board.

  1. Study TC0, TC1 and TC2 architectures of Atmega328 (these are similar to ATtiny85) in order to
    manipulate register contents for the generation of PWM signals of your need.

  2. The attached files might help you in this regard!

Experimentpwm.PDF (532 KB)

P72OC2BPWM.ino (851 Bytes)