from machine import Pin
import utime

# Setup Pins
sdi = Pin(13, Pin.OUT)
rclk = Pin(14, Pin.OUT)
srclk = Pin(15, Pin.OUT)

# Segment patterns for 0-9 (Common Cathode)
digits = [0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f]

def shift_out_16(tens_val, ones_val):
    """Pushes 16 bits to the daisy-chained registers."""
    rclk.low()
    # We send the 'ones' first so it ends up in the second register (Display 2)
    # The 'tens' follows it and stays in the first register (Display 1)
    for byte in [ones_val, tens_val]:
        for i in range(8):
            srclk.low()
            bit = (byte >> (7 - i)) & 0x01
            sdi.value(bit)
            srclk.high()
    rclk.high()

# Main Counter Loop
while True:
    for count in range(100):  # Counts from 0 to 99
        tens = count // 10
        ones = count % 10
        
        # Get the segment patterns and update
        shift_out_16(digits[tens], digits[ones])
        
        # Wait half a second before the next number
        utime.sleep(0.5)