'''
SRCLK = 16
SER = 2
RCLK = 18

FW:
Create a class object called Port.
This class hold a 16-bit parameter of a double 74595 shift register.
The class has the following methods:

1. def set_bit(bit_number):
        # This will set a specific bit in the 16-bit register.
2. def clear_bit(bit_number):
        # This will clear a specific bit in the 16-bit register.
3. reg_write(data):
        # This will write a 16-bit value to the register in parallel.
 
'''

from machine import Pin
import time

SRCLK = Pin(16,Pin.OUT,value=0)
SER = Pin(2,Pin.OUT,value=0)
RCLK = Pin(18,Pin.OUT,value=0)

def reg_write(data):
    for i in range(0,16):
        val = data & 0x0001
        SER.value(val)
        data = data >> 1
        SRCLK.value(1)
        time.sleep(0.0005) # 500usec = 0.5msec
        SRCLK.value(0)
        time.sleep(0.0005) # 500usec = 0.5msec
    RCLK.value(1)
    time.sleep(0.0005) # 500usec = 0.5msec
    RCLK.value(0)

reg_write(0xFFFF)
time.sleep(5)

count = 0
while True:
    reg_write(count)
    time.sleep(0.5)
    count = count + 1