// Sensorless brushless DC (BLDC) motor control with Arduino UNO and IR2101 (Arduino DIY ESC). // This is a free software without any warranty. #define SPEED_UP A0 // BLDC motor speed-up button #define SPEED_DOWN A1 // BLDC motor speed-down button #define PWM_MAX_DUTY 255 #define PWM_MIN_DUTY 50 #define PWM_START_DUTY 100 byte bldc_step = 0, motor_speed; unsigned int i; void setup() { DDRD |= 0x38; // Configure pins 3, 4 and 5 as outputs PORTD = 0x00; DDRB |= 0x0E; // Configure pins 9, 10 and 11 as outputs PORTB = 0x31; // Timer1 module setting: set clock source to clkI/O / 1 (no prescaling) TCCR1A = 0; TCCR1B = 0x01; // Timer2 module setting: set clock source to clkI/O / 1 (no prescaling) TCCR2A = 0; TCCR2B = 0x01; // Analog comparator setting ACSR = 0x10; // Disable and clear (flag bit) analog comparator interrupt pinMode(SPEED_UP, INPUT_PULLUP); pinMode(SPEED_DOWN, INPUT_PULLUP); } // Analog comparator ISR ISR (ANALOG_COMP_vect) { // BEMF debounce for(i = 0; i < 10; i++) { if(bldc_step & 1){ if(!(ACSR & 0x20)) i -= 1; } else { if((ACSR & 0x20)) i -= 1; } } bldc_move(); bldc_step++; bldc_step %= 6; } void bldc_move(){ // BLDC motor commutation function switch(bldc_step){ case 0: AH_BL(); BEMF_C_RISING(); break; case 1: AH_CL(); BEMF_B_FALLING(); break; case 2: BH_CL(); BEMF_A_RISING(); break; case 3: BH_AL(); BEMF_C_FALLING(); break; case 4: CH_AL(); BEMF_B_RISING(); break; case 5: CH_BL(); BEMF_A_FALLING(); break; } } void loop() { SET_PWM_DUTY(PWM_START_DUTY); // Setup starting PWM with duty cycle = PWM_START_DUTY i = 5000; // Motor start while(i > 100) { delayMicroseconds(i); bldc_move(); bldc_step++; bldc_step %= 6; i = i - 20; } motor_speed = PWM_START_DUTY; ACSR |= 0x08; // Enable analog comparator interrupt while(1) { while(!(digitalRead(SPEED_UP)) && motor_speed < PWM_MAX_DUTY){ motor_speed++; SET_PWM_DUTY(motor_speed); delay(100); } while(!(digitalRead(SPEED_DOWN)) && motor_speed > PWM_MIN_DUTY){ motor_speed--; SET_PWM_DUTY(motor_speed); delay(100); } } } void BEMF_A_RISING(){ ADCSRB = (0 << ACME); // Select AIN1 as comparator negative input ACSR |= 0x03; // Set interrupt on rising edge } void BEMF_A_FALLING(){ ADCSRB = (0 << ACME); // Select AIN1 as comparator negative input ACSR &= ~0x01; // Set interrupt on falling edge } void BEMF_B_RISING(){ ADCSRA = (0 << ADEN); // Disable the ADC module ADCSRB = (1 << ACME); ADMUX = 2; // Select analog channel 2 as comparator negative input ACSR |= 0x03; } void BEMF_B_FALLING(){ ADCSRA = (0 << ADEN); // Disable the ADC module ADCSRB = (1 << ACME); ADMUX = 2; // Select analog channel 2 as comparator negative input ACSR &= ~0x01; } void BEMF_C_RISING(){ ADCSRA = (0 << ADEN); // Disable the ADC module ADCSRB = (1 << ACME); ADMUX = 3; // Select analog channel 3 as comparator negative input ACSR |= 0x03; } void BEMF_C_FALLING(){ ADCSRA = (0 << ADEN); // Disable the ADC module ADCSRB = (1 << ACME); ADMUX = 3; // Select analog channel 3 as comparator negative input ACSR &= ~0x01; } void AH_BL(){ PORTD &= ~0x28; PORTD |= 0x10; TCCR1A = 0; // Turn pin 11 (OC2A) PWM ON (pin 9 & pin 10 OFF) TCCR2A = 0x81; // } void AH_CL(){ PORTD &= ~0x30; PORTD |= 0x08; TCCR1A = 0; // Turn pin 11 (OC2A) PWM ON (pin 9 & pin 10 OFF) TCCR2A = 0x81; // } void BH_CL(){ PORTD &= ~0x30; PORTD |= 0x08; TCCR2A = 0; // Turn pin 10 (OC1B) PWM ON (pin 9 & pin 11 OFF) TCCR1A = 0x21; // } void BH_AL(){ PORTD &= ~0x18; PORTD |= 0x20; TCCR2A = 0; // Turn pin 10 (OC1B) PWM ON (pin 9 & pin 11 OFF) TCCR1A = 0x21; // } void CH_AL(){ PORTD &= ~0x18; PORTD |= 0x20; TCCR2A = 0; // Turn pin 9 (OC1A) PWM ON (pin 10 & pin 11 OFF) TCCR1A = 0x81; // } void CH_BL(){ PORTD &= ~0x28; PORTD |= 0x10; TCCR2A = 0; // Turn pin 9 (OC1A) PWM ON (pin 10 & pin 11 OFF) TCCR1A = 0x81; // } void SET_PWM_DUTY(byte duty){ if(duty < PWM_MIN_DUTY) duty = PWM_MIN_DUTY; if(duty > PWM_MAX_DUTY) duty = PWM_MAX_DUTY; OCR1A = duty; // Set pin 9 PWM duty cycle OCR1B = duty; // Set pin 10 PWM duty cycle OCR2A = duty; // Set pin 11 PWM duty cycle }