MicroPython 7-segment digit through a 74HC595 on an ESP32-DevKitC V4

# One 7-segment digit through a 74HC595: the digit counts 0 to F, half
# a second each. The display is common anode, so a segment lights when
# its output is 0. Bits go out with DP first and A last, so Q7 drives A.
from hc595 import HC595
import time

chip = HC595(15, 2, 4)        # DS on 15, ST_CP on 2, SH_CP on 4
# bit 7 is DP ... bit 0 is A, so these read as DP G F E D C B A
digits = [0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90, 0x88, 0x83, 0xc6, 0xa1, 0x86, 0x8e]

while True:
    for n, pattern in enumerate(digits):
        chip.write(pattern, msb_first=False)
        print("digit %X" % n)
        time.sleep_ms(500)

# hc595.py: send a byte to a 74HC595 on three pins.
# data is DS, latch is ST_CP and clock is SH_CP. Each bit is set on DS
# and clocked in on a rising SH_CP; a rising ST_CP shows all eight.
from machine import Pin

class HC595:
    def __init__(self, data, latch, clock, oe=None):
        self.data = Pin(data, Pin.OUT, value=0)
        self.latch = Pin(latch, Pin.OUT, value=0)
        self.clock = Pin(clock, Pin.OUT, value=0)
        if oe is not None:
            self.oe = Pin(oe, Pin.OUT, value=0)    # OE low: the outputs are on

    def shift(self, value, msb_first=True):
        for i in range(8):
            bit = 7 - i if msb_first else i
            self.data.value((value >> bit) & 1)
            self.clock.value(1)
            self.clock.value(0)

    def write(self, value, msb_first=True):
        self.latch.value(0)
        self.shift(value, msb_first)
        self.latch.value(1)