twos_compliment_MicroBit.py

# Mr. Coxall
from microbit import *

def convert_dec_to_bin(int_number, binary_digits):
	# convert a decimal number to binary stored in an array
	
	if int_number < 0:
		# it is a negative number
		positive_equivalent = pow(2, binary_digits)-abs(int_number)-1
		answer = bin(~positive_equivalent)
		
		answer_array = list(answer)
		answer_array.pop(0)
		answer_array.pop(0)
		answer_array.pop(0)
	else:
		answer = bin(int_number)
		answer_array = list(answer)
		answer_array.pop(0)
		answer_array.pop(0)
		# now pad the front with 0s
		while len(answer_array) < binary_digits:
			answer_array.insert(0, 0)
		
	answer_array = list(map(int, answer_array))
	return answer_array

# starting values
start_number = -8
end_number = 7
number_of_binary_digits = 4

pin0.write_digital(0)
pin1.write_digital(0)
pin2.write_digital(0)
pin8.write_digital(0)
pin12.write_digital(0)
pin13.write_digital(0)
pin14.write_digital(0)
pin15.write_digital(0)

display.show(Image.YES)
sleep(500)

# variable holding the decimal value of a button
a_input = 0
a_input_as_binary = []
b_input = 0
b_input_as_binary = []

while True:
    display.clear()
    
    for b_input in range(start_number, end_number+1):
        for a_input in range(start_number, end_number+1):
            # convert decimal to binary
            a_input_as_binary = convert_dec_to_bin(a_input, number_of_binary_digits)
            b_input_as_binary = convert_dec_to_bin(b_input, number_of_binary_digits)
            
            # turn on the digital pins
            #display.scroll(str(a_input_as_binary))
            pin0.write_digital(int(a_input_as_binary[3]))
            pin1.write_digital(int(a_input_as_binary[2]))
            pin2.write_digital(int(a_input_as_binary[1]))
            pin8.write_digital(int(a_input_as_binary[0]))
            
            #display.scroll(str(b_input_as_binary))
            pin12.write_digital(int(b_input_as_binary[3]))
            pin13.write_digital(int(b_input_as_binary[2]))
            pin14.write_digital(int(b_input_as_binary[1]))
            pin15.write_digital(int(b_input_as_binary[0]))
            
            display.scroll(str(a_input) + "+" + str(b_input) + "=" + str(a_input+b_input))
            sleep(500)