from machine import Pin
import time

sclk = Pin(10, Pin.OUT)
mosi = Pin(11, Pin.OUT)
miso = Pin(12, Pin.IN)
cs = Pin(13, Pin.OUT)

sclk.value(0)
cs.value(1)

def spi_transfer_byte(data_out):
    data_in = 0
    cs.value(0)
    for i in range(8):
        bit_to_send = (data_out >> (7 - i)) & 1
        mosi.value(bit_to_send)
        sclk.value(1)
        if miso.value() == 1:
            data_in |= (1 << (7 - i))
        
        sclk.value(0)

    cs.value(1)
    return data_in

print("SPI Ready!")
print("Type a message and press Enter:")

while True:
    user_text = input().strip()
    if user_text:
        received_text = ""
        for char in user_text:
            byte_to_transmit = ord(char)
            received_byte = spi_transfer_byte(byte_to_transmit)
            received_text += chr(received_byte)
        print(f"Original String : {user_text}")
        print(f"Received String : {received_text}")
        print("-" * 10)