Mega 10bits pwm - pwm mode

Projects Programming
1

Goodmorning everybody!

I'm trying to implement 10bits resolution and 10kHz pwm frequency for my auto balancing robot.
Pololu - Dual VNH3SP30 Motor Driver Carrier MD03A (max pwm frequency 10kHz)
https://www.sparkfun.com/products/9947
https://www.pololu.com/product/1443

For the mega2560 16 bits timers are 1,3,4,5:

timer 1 for pin 11 12
timer 3 for pin 2 3 5
timer 4 for pin 6 7 8
timer 5 for pin 44 45 46

I want to use timer5 and here Advanced Arduino: direct use of ATmega counter/timers at the end of the page shows pem modes: Fast Pwm at different resolutions, phase correct, phase and frequency correct. I usually read balancebot codes using phase and frequency, but don't really know why and how to set it in code.

 #include <avr/io.h>
  
  void setup(){
   pinMode(44, OUTPUT); 
   pinMode(45, OUTPUT); 
  }
  
  void loop(){
  main();
  }  
  
  void main(){  
  // In the next line of code, we:
  // 1. Set the compare output mode to clear OC2A and OC2B on compare match.
  //    To achieve this, we set bits COM2A1 and COM2B1 to high.
  // 2. Set the waveform generation mode to fast PWM (mode 3 in datasheet).
  //    To achieve this, we set bits WGM21 and WGM20 to high.
  TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM21) | _BV(WGM20);
//not able to understand HOW CAN I CHANGE THAT MODE

  // In the next line of code, we:
  // 1. Set the waveform generation mode to fast PWM mode 7 —reset counter on
  //    OCR2A value instead of the default 255. To achieve this, we set bit
  //    WGM22 to high.
  // 2. Set the prescaler divisor to 1, so that our counter will be fed with
  //    the clock's full frequency (16MHz). To achieve this, we set CS20 to
  //    high (and keep CS21 and CS22 to low by not setting them).
 // TCCR2B = _BV(WGM22) | _BV(CS20);

 TCCR5B = B10010;  // prescaling by 8 the system clock

  // OCR2A holds the top value of our counter, so it acts as a divisor to the
  // clock. When our counter reaches this, it resets. Counting starts from 0.
  // Thus 63 equals to 64 divs.
  // OCR2A = 63;

 OCR5A = 14970; // 66,8002672Hz 

  // This is the duty cycle. Think of it as the last value of the counter our
  // output will remain high for. Can't be greater than OCR2A of course. A
  // value of 0 means a duty cycle of 1/64 in this case.
  
OCR5A = 0;   
  
  while(1);
  }

Moderator edit:
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2

I'm trying to implement 10bits resolution and 10kHz pwm frequency

Well, you won't get both at the same time - that would imply a clock frequency of 10.24MHz. With the 16MHz AVR, you can clock your PWM at either 16MHz which will give you 10kHz PWM with slightly more than 10bits of resolution ("top" = 1600), or you can run 8MHz with somewhat less than 10bits resolution (top=800)

 // OCR2A holds the top value of our counter, so it acts as a divisor to the

// clock. When our counter reaches this, it resets. Counting starts from 0.
 // Thus 63 equals to 64 divs.
 // OCR2A = 63;

OCR5A = 14970; // 66,8002672Hz

Assuming your comments are correct, you'd want to set OCR5A to 1599 to get 10kHz (16M/10k = 1600), and you'd have 0..1599 as your PWM choices.

3

I do not understand how to choose the right COM WGM snd CS for timer5... >:(
What does _BV() function set? the bits high?

TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM21) | _BV(WGM20);
TCCR2B = _BV(WGM22) | _BV(CS20);

This is the original code:

  // In the next line of code, we:
  // 1. Set the compare output mode to clear OC2A and OC2B on compare match.
  //    To achieve this, we set bits COM2A1 and COM2B1 to high.
  // 2. Set the waveform generation mode to fast PWM (mode 3 in datasheet).
  //    To achieve this, we set bits WGM21 and WGM20 to high.
  TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM21) | _BV(WGM20);

  // In the next line of code, we:
  // 1. Set the waveform generation mode to fast PWM mode 7 --reset counter on
  //    OCR2A value instead of the default 255. To achieve this, we set bit
  //    WGM22 to high.
  // 2. Set the prescaler divisor to 1, so that our counter will be fed with
  //    the clock's full frequency (16MHz). To achieve this, we set CS20 to
  //    high (and keep CS21 and CS22 to low by not setting them).
  TCCR2B = _BV(WGM22) | _BV(CS20);


  // OCR2A holds the top value of our counter, so it acts as a divisor to the
  // clock. When our counter reaches this, it resets. Counting starts from 0.
  // Thus 63 equals to 64 divs.
  // OCR2A = 63;
  OCR5A = 1599; // 10kHz 

  // This is the duty cycle. Think of it as the last value of the counter our
  // output will remain high for. Can't be greater than OCR2A of course. A
  // value of 0 means a duty cycle of 1/64 in this case.
  OCR5A = 0;
4

What does _BV() function set? the bits high?

Yes, it sets a bit high in the register location used as an argument for the function.

I do not understand how to choose the right COM WGM snd CS for timer5..

It will all be explained in the data sheet for the ATmega 640-1280-1281-2560-2561