import time        # Import time module for delay
import board       # Import board module to access GPIO pins
import digitalio   # Import digital I/O control library


bcd_tens = [board.GP2, board.GP3, board.GP4, board.GP5]   # Define BCD pins for tens digit
bcd_ones = [board.GP6, board.GP7, board.GP8, board.GP9]   # Define BCD pins for ones digit


class CD4511:   # Create class to control CD4511 IC
    
    def __init__(self, pins):   # Constructor to initialize pins
        self.bcd = []   # Create list to store pin objects
        
        for pin in pins:   # Loop through each pin
            p = digitalio.DigitalInOut(pin)   # Create DigitalInOut object
            p.direction = digitalio.Direction.OUTPUT   # Set pin as output
            self.bcd.append(p)   # Add pin to list

    def display(self, num):   # Function to display number
        
        num = max(0, min(9, num))   # Limit number between 0 and 9
        
        for i in range(4):   # Loop through 4 bits (A, B, C, D)
            self.bcd[i].value = (num >> i) & 1   # Send BCD value to CD4511


tens_disp = CD4511(bcd_tens)   # Create object for tens display
ones_disp = CD4511(bcd_ones)   # Create object for ones display


sw_up = digitalio.DigitalInOut(board.GP15)   # Define UP button pin
sw_up.direction = digitalio.Direction.INPUT   # Set as input
sw_up.pull = digitalio.Pull.UP   # Enable internal pull-up resistor

sw_down = digitalio.DigitalInOut(board.GP16)   # Define DOWN button pin
sw_down.direction = digitalio.Direction.INPUT   # Set as input
sw_down.pull = digitalio.Pull.UP   # Enable internal pull-up resistor


count = 0   # Initialize counter value


while True:   # Infinite loop to keep program running

    if not sw_up.value:   # Check if UP button is pressed (LOW)
        count = (count + 1) % 100   # Increase counter from 0 to 99
        print("UP:", count)   # Print value to serial monitor
        time.sleep(0.2)   # Small delay to avoid multiple counts

    if not sw_down.value:   # Check if DOWN button is pressed
        count = (count - 1) % 100   # Decrease counter with wrap-around
        print("DOWN:", count)   # Print value to serial monitor
        time.sleep(0.2)   # Delay for debounce

    tens = count // 10   # Get tens digit using integer division
    ones = count % 10   # Get ones digit using modulus

    tens_disp.display(tens)   # Send tens digit to first display
    ones_disp.display(ones)   # Send ones digit to second display