from machine import Pin
import time

# Set up input pins for number A (2-bit)
a0 = Pin(6, Pin.IN, Pin.PULL_DOWN)
a1 = Pin(7, Pin.IN, Pin.PULL_DOWN)

# Set up input pins for number B (2-bit)
b0 = Pin(8, Pin.IN, Pin.PULL_DOWN)
b1 = Pin(9, Pin.IN, Pin.PULL_DOWN)

# Set up output pins for LEDs (result)
leds = [
    Pin(2, Pin.OUT),  # R0 (lowest bit)
    Pin(3, Pin.OUT),  # R1
    Pin(4, Pin.OUT),  # R2
    Pin(5, Pin.OUT)   # R3 (highest bit)
]

# Function to show result on LEDs
def show_binary(value):
    for i in range(4):
        leds[i].value((value >> i) & 1)

while True:
    # Read 2-bit numbers A and B
    a = a0.value() + (a1.value() << 1)
    b = b0.value() + (b1.value() << 1)
    
    result = a + b  # Add the numbers
    show_binary(result)  # Show result on LEDs

    time.sleep(0.1)  # Small delay to stabilize