Simple test

Ensure your device works with this simple test.

examples/74hc595_simpletest.py

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import busio
import digitalio
import adafruit_74hc595

spi = busio.SPI(board.SCK, MOSI=board.MOSI)

latch_pin = digitalio.DigitalInOut(board.D5)
sr = adafruit_74hc595.ShiftRegister74HC595(spi, latch_pin)

pin1 = sr.get_pin(1)

while True:
    pin1.value = True
    time.sleep(1)
    pin1.value = False
    time.sleep(1)