Machine Building Preparation

Board

Ref. Norwway bootcamp

FAB25(Moduler Things)	BootCamp Leon2024	BootCamp Norway2026
OA2, OA1, OB1, OB2	OA1, OA2, OB1, OB2	Out1, Out2, Out3, Out4 (OA1, OA2, OB1, OB2)
stepperDriver.cpp
#define AIN1_PIN 6 // on D4	#define AIN1_PIN 7 // on D5	#define AIN1_PIN 29 //(IN1) on D3
#define AIN2_PIN 7 // on D5	#define AIN2_PIN 0 // on D6	#define AIN2_PIN 6 //(IN2) on D4
#define BIN1_PIN 28 // on D2	#define BIN1_PIN 2 // on D8	#define BIN1_PIN 4 //(IN3) on D2
#define BIN2_PIN 4 // on D9	#define BIN2_PIN 4 // on D9	#define BIN2_PIN 28 //(IN4) on D9
#define APWM_PIN 27 // on D1	#define APWM_PIN 6 // on D4
#define BPWM_PIN 29 // on D3	#define BPWM_PIN 3 // on D10
simple_stepper.ino
#define PIN_LIMIT 26 // on D0	#define PIN_LIMIT 29 // on D3	#define PIN_LIMIT 26 // on D0

.
└── simple_stepper
    ├── cobs.cpp
    ├── cobs.h
    ├── COBSUSBSerial.cpp
    ├── COBSUSBSerial.h
    ├── fixedPointUtes.cpp
    ├── fixedPointUtes.h
    ├── lutgen.js
    ├── motionStateMachine.cpp
    ├── motionStateMachine.h
    ├── serializationUtes.cpp
    ├── serializationUtes.h
    ├── simple_stepper.ino
    ├── stepperDriver.cpp
    ├── stepperDriver.h
    └── stepperLUT.h

Stepper Motors

Nema 17

DRV8421A sample code

// Pin definitions for XIAO
#define AIN1_PIN 29  // DRV8421A IN1
#define AIN2_PIN 6   // DRV8421A IN2
#define BIN1_PIN 4   // DRV8421A IN3
#define BIN2_PIN 28  // DRV8421A IN4

// PWM value to limit effective voltage to 2.8V with a 5.0V supply
// Calculation: 255 * (2.8V / 5.0V) approx 143
const int limitPWM = 143; 

// Step speed in microseconds (lower is faster)
int stepDelayUs = 3000; 

// Steps required for a 360-degree rotation (360 / 1.8 = 200 steps)
const int stepsPerRev = 200;

void setup() {
  // Set all control pins as outputs
  pinMode(AIN1_PIN, OUTPUT);
  pinMode(AIN2_PIN, OUTPUT);
  pinMode(BIN1_PIN, OUTPUT);
  pinMode(BIN2_PIN, OUTPUT);
}

/**
 * Sends control signals to the 4-wire input of DRV8421A.
 * Uses analogWrite for HIGH states to limit the motor current.
 */
void setStep(bool a1, bool a2, bool b1, bool b2) {
  // Phase A control
  if (a1) analogWrite(AIN1_PIN, limitPWM); else digitalWrite(AIN1_PIN, LOW);
  if (a2) analogWrite(AIN2_PIN, limitPWM); else digitalWrite(AIN2_PIN, LOW);

  // Phase B control
  if (b1) analogWrite(BIN1_PIN, limitPWM); else digitalWrite(BIN1_PIN, LOW);
  if (b2) analogWrite(BIN2_PIN, limitPWM); else digitalWrite(BIN2_PIN, LOW);

  delayMicroseconds(stepDelayUs);
}

// Perform a 360-degree forward rotation
void moveForward() {
  for (int i = 0; i < stepsPerRev; i++) {
    int phase = i % 4;
    switch(phase) {
      // Full-Step sequence based on data sheet Figure 7-4
      case 0: setStep(true,  false, true,  false); break; // Step 1
      case 1: setStep(false, true,  true,  false); break; // Step 2
      case 2: setStep(false, true,  false, true);  break; // Step 3
      case 3: setStep(true,  false, false, true);  break; // Step 4
    }
  }
}

// Perform a 360-degree backward rotation
void moveBackward() {
  for (int i = 0; i < stepsPerRev; i++) {
    int phase = i % 4;
    switch(phase) {
      // Reverse of the Full-Step sequence
      case 0: setStep(true,  false, false, true);  break; // Step 4 rev
      case 1: setStep(false, true,  false, true);  break; // Step 3 rev
      case 2: setStep(false, true,  true,  false); break; // Step 2 rev
      case 3: setStep(true,  false, true,  false); break; // Step 1 rev
    }
  }
}

void loop() {
  // 1. Rotate 360 degrees forward
  moveForward();
  delay(1000); // Wait for 1 second

  // 2. Rotate 360 degrees backward
  moveBackward();
  delay(1000); // Wait for 1 second
}