Add A4988 stepper motor driver

micropython/drivers/a4988/a4988.py

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+import time
+
+# Constants
+STEPS_PER_REV = 200  # Number of steps per motor revolution
+MIN_DELAY = 0.001  # Minimum delay between steps (controls maximum speed)
+
+# Function to enable or disable the motor driver (active low)
+def enable_motor(EN_PIN, enabled=True):
+    """Enable or disable the motor driver."""
+    EN_PIN.value(0 if enabled else 1)
+
+# Function to move the motor a specific number of steps
+def step_motor(STEP_PIN, DIR_PIN, steps=STEPS_PER_REV, direction=1, delay=0.005):
+    """Move the motor a specified number of steps in the given direction."""
+    DIR_PIN.value(direction)  # Set direction (1 = forward, 0 = backward)
+    for _ in range(steps):
+        STEP_PIN.value(1)
+        time.sleep(delay)
+        STEP_PIN.value(0)
+        time.sleep(delay)
+
+# Function to calculate current speed in steps per second and RPM
+def calculate_speed(current_delay):
+    """Calculate the current speed in steps per second and RPM."""
+    if current_delay <= 0:
+        return 0, 0
+    steps_per_second = 1 / (2 * current_delay)  # Delay is for each half-step
+    rpm = (steps_per_second / STEPS_PER_REV) * 60  # Convert to RPM
+    return steps_per_second, rpm
+
+# Function to increase motor speed by reducing delay
+def inc_speed(current_delay):
+    """Decrease delay to increase speed, respecting minimum delay limit."""
+    new_delay = max(current_delay - 0.001, MIN_DELAY)
+    return new_delay
+
+# Function to decrease motor speed by increasing delay
+def dec_speed(current_delay):
+    """Increase delay to decrease speed."""
+    new_delay = current_delay + 0.001
+    return new_delay
+
+# Function to move motor forward
+def forward_motion(STEP_PIN, DIR_PIN, steps=STEPS_PER_REV, delay=0.005):
+    """Move motor forward for a given number of steps and delay."""
+    step_motor(STEP_PIN, DIR_PIN, steps, direction=1, delay=delay)
+
+# Function to move motor backward
+def backward_motion(STEP_PIN, DIR_PIN, steps=STEPS_PER_REV, delay=0.005):
+    """Move motor backward for a given number of steps and delay."""
+    step_motor(STEP_PIN, DIR_PIN, steps, direction=0, delay=delay)

micropython/drivers/a4988/a4988_test.py

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+from machine import Pin
+import time
+import a4988  # Import functions from the A4988 motor driver module
+
+# Define motor control pins
+DIR_PIN = Pin(12, Pin.OUT)    # Direction pin
+STEP_PIN = Pin(14, Pin.OUT)   # Step pin (controls motor steps)
+EN_PIN = Pin(21, Pin.OUT)     # Enable pin for motor driver
+
+# Define pins for switches
+switch_forward = Pin(26, Pin.IN)     # Forward motion switch
+switch_backward = Pin(27, Pin.IN)    # Backward motion switch
+speed_increase = Pin(33, Pin.IN)     # Speed increase switch
+speed_decrease = Pin(32, Pin.IN)     # Speed decrease switch
+
+# Initialize motor driver
+a4988.enable_motor(EN_PIN, enabled=True)
+
+# Set initial motor speed and debounce delay
+current_delay = 0.005  # Initial delay between steps for motor speed
+prev_speed_inc_state = 0
+prev_speed_dec_state = 0
+debounce_delay = 0.1  # Delay to avoid switch bouncing effects
+
+# Main control loop
+while True:
+    # Motor directional control
+    if switch_forward.value() == 1:
+        a4988.forward_motion(STEP_PIN, DIR_PIN, a4988.Steps, delay=current_delay)
+    elif switch_backward.value() == 1:
+        a4988.backward_motion(STEP_PIN, DIR_PIN, a4988.Steps, delay=current_delay)
+
+    # Speed increase control
+    current_inc_state = speed_increase.value()
+    if current_inc_state == 1 and prev_speed_inc_state == 0:
+        current_delay = a4988.inc_speed(current_delay)
+    prev_speed_inc_state = current_inc_state  # Update state for next loop
+
+    # Speed decrease control
+    current_dec_state = speed_decrease.value()
+    if current_dec_state == 1 and prev_speed_dec_state == 0:
+        current_delay = a4988.dec_speed(current_delay)
+    prev_speed_dec_state = current_dec_state  # Update state for next loop
+
+    # Small delay to debounce switch inputs and stabilize loop
+    time.sleep(debounce_delay)

micropython/drivers/a4988/manifest.py

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+metadata(description="MicroPython driver for A4988 stepper motor controller", version="1.0.0")