Hi, for school we need to program a Zumo32u4 robot. Currently we’re trying to get the robot to drive, but after fully initiating the timer 1 according to the datasheet, our knowledge of microcontrollers, our experience with the Atmega328p and using the zumo library as an example, it doesn’t seem to work. I’ll share the code we have made with you guys:

```
void initTimer1PWM(){
//TCCR1A = (1 << COM1A1) | (1 << WGM10);
//ICR1 = 400;
//TCCR1B = (1 << WGM12);
TCCR1A = 0b10100000;
TCCR1B = 0b00010001;
ICR1 = 400;
OCR1A = 0;
OCR1B = 0;
}
void setRightSpeed(int16_t speed){
initTimer1PWM();
int reverse = 0;
if (speed < 0)
{
speed = -speed; // Make speed a positive quantity.
reverse = 1; // Preserve the direction.
}
if (speed > 400) // Max PWM duty cycle.
{
speed = 400;
}
if(reverse==1){
PORTB = (1<<PORTB1);
}
if(reverse==0){
PORTB = ~(1<<PORTB1);
}
OCR1A = speed;
}
```

This is pretty much the Zumo library code for the motors copied and pasted, then made to work without the rest of the library. I didn’t include setLeftSpeed as it’s the same, but with OCR1B and using PORTB2 for direction. The resulting behavior is that the motor runs at a total max speed, no speed control, as well as some direction problems. If we set up the right motor only then that one will run at full speed forward or backward like it should, but the other motor will also run but in the opposite direction of the other one. Same result if we set up the left motor but then reversed, the left motor drives forward while the right motor backwards. This is not supposed to happen, the expected result is that only one motor turns on at all, and the speed control should work.

If you think the direction problem is a bitshifting problem, if we use

```
PORTB |= (1 << PORTB1)
PORTB &= ~(1 << PORTB1)
```

the whole thing just refuses to drive at all.

Our teacher has looked at it, he doesn’t know what to do. A friend whose thesis is about microcontrollers doesn’t know what’s wrong. We’re at a total loss. It would be amazing if anyone here could find the problem.

btw, we’re not allowed to directly use the Zumo library or any library for that matter except the standard AVR ones, just so you know.

Much thanks in advance!