Simple NTP clock for any generic board with built-in display and wifi

code_clock.py

import board
import time
import uiclock_lib as uiclock

# timezone offset in seconds (fomr UTC)
TZ_OFFSET = 3600 * 2

current_time = None

def update_time(text_label):
    global current_time
    now = time.localtime()
    if current_time != now:
        text_label.text = "{hour:02d}:{min:02d}:{seconds:02d}".format(hour = now.tm_hour, min = now.tm_min, seconds = now.tm_sec)
        current_time = now

display = board.DISPLAY
text_label = uiclock.init_ui(display)
time.sleep(1)

uiclock.connect_wifi(verbose=True)
text_label.text = "Connected"
time.sleep(1)

now = uiclock.set_ntp_time(TZ_OFFSET)
print("Synced with NTP")
text_label.text = "Synced"
time.sleep(1.0)

while True:
    update_time(text_label)
    time.sleep(0.2)
    #display.rotation = (display.rotation + 180) % 360

secrets.py

# fill in and uncomment the secrets dictionary
# secrets = {
# 	'ssid' : "YOURSSID",
# 	'password' : "YOURPASSWORD",
# }

uiclock_lib.py

import board
import rtc
import struct
import time

FONTSCALE = 3
BORDER_WIDTH = 10
BORDER_COLOR = 0x004488
BACKGROUND_COLOR = 0x000022
TEXT_COLOR = 0xd257ff

TZ_OFFSET = 3600 * 2
NTP_TIME_CORRECTION = 2_208_988_800
NTP_SERVER = "pool.ntp.org"
NTP_PORT = 123

socket_pool = None
ssl_context = None

def init_ui(display,
        text="Starting", *,
        border_color=BORDER_COLOR,
        background=BACKGROUND_COLOR,
        text_color=TEXT_COLOR,
        border=BORDER_WIDTH):
    import terminalio
    import displayio
    from adafruit_display_text import label

    splash = displayio.Group()
    display.show(splash)

    color_bitmap = displayio.Bitmap(display.width, display.height, 1)
    color_palette = displayio.Palette(1)
    color_palette[0] = border_color

    bg_sprite = displayio.TileGrid(color_bitmap, pixel_shader=color_palette, x=0, y=0)
    splash.append(bg_sprite)

    # Draw a smaller inner rectangle
    inner_bitmap = displayio.Bitmap(display.width - border * 2, display.height - border * 2, 1)
    inner_palette = displayio.Palette(1)
    inner_palette[0] = background
    inner_sprite = displayio.TileGrid(inner_bitmap, pixel_shader=inner_palette, x=border, y=border)
    splash.append(inner_sprite)

    text_label = label.Label(terminalio.FONT, color=text_color, text=text, anchor_point=(0.5, 0.5))
    text_width = text_label.bounding_box[2] * FONTSCALE
    text_group = displayio.Group(
            scale=FONTSCALE,
            x=display.width // 2 - text_width // 2,
            y=display.height // 2,
    )
    text_group.append(text_label)
    splash.append(text_group)

    return text_label

def connect_wifi(verbose=False):
    global socket_pool
    import wifi
    import socketpool
    try:
        from secrets import secrets
    except ImportError:
        print("WiFi secrets are kept in secrets.py, please add them there!")
        raise
    if verbose:
        print("Connecting to ", secrets["ssid"])
    wifi.radio.connect(ssid=secrets["ssid"], password=secrets["password"])
    socket_pool = socketpool.SocketPool(wifi.radio)
    if verbose:
        print("Connected with IP ", wifi.radio.ipv4_address)

def get_ntp_time(pool, offset):
    packet = bytearray(48)
    packet[0] = 0b00100011

    for i in range(1, len(packet)):
        packet[i] = 0

    with pool.socket(pool.AF_INET, pool.SOCK_DGRAM) as sock:
        sock.settimeout(None)
        sock.sendto(packet, (NTP_SERVER, NTP_PORT))
        sock.recv_into(packet)
        destination = time.monotonic_ns()

    seconds = struct.unpack_from("!I", packet, offset=len(packet) - 8)[0]
    monotonic_start = seconds - NTP_TIME_CORRECTION - (destination // 1_000_000_000)
    return time.localtime(time.monotonic_ns() // 1_000_000_000 + monotonic_start + offset)

def set_ntp_time(offset=TZ_OFFSET):
    now = get_ntp_time(socket_pool, offset)
    rtc.RTC().datetime = now

def setup_requests():
    global socket_pool
    global ssl_context
    import ssl
    import adafruit_requests
    if not ssl_context:
        ssl_context = ssl.create_default_context()
    requests = adafruit_requests.Session(socket_pool, ssl_context)
    return requests

def _test():
    display = board.DISPLAY
    text_label = init_ui(display)
    return (display,text_label)