import time
from datetime import datetime, timedelta
 
from luma.led_matrix.device import max7219
from luma.led_matrix.virtual import sevensegment
from luma.core.serial import spi, noop

def countdown(seg, seconds):
    end = datetime.now() + timedelta(0, seconds)
    current = datetime.now()
    while current < end:
        sec = (end - current).seconds
        dezsec = (end - current).microseconds / 10000
        seg.text = ("           %d.%d" % (sec, dezsec) )[-9:]
        time.sleep(0.05)
        current = datetime.now()


if __name__ == '__main__':

    serial = spi(port=0, device=0, gpio=noop())
    device = max7219(serial, cascaded=1)
    seg = sevensegment(device)

    countdown(seg, 15)