Network sockets with Micropython on an Arduino Nano RP2040

[ScooterKraig]

I'm trying to get the time, with Micropython on an Arduino Nano RP2040 Connect but I'm getting the following error:

ip = 192.168.1.190
OS Error 
<socket fd=-1 timeout=-1 domain=2 type=2 proto=0 bound=false>
Traceback (most recent call last):
  File "<stdin>", line 143, in <module>
  File "<stdin>", line 70, in reset_clock
NameError: local variable referenced before assignment

The problem seems to be with the "addr = socket.getaddrinfo(host, 123)[0][-1]" command. "getaddrinfo" does not seem to return an address (addr).

This code works fine with a real Raspberry Pi Pico W, and with a Raspberry Zero W. What could be going on? Is there some difference in the implementation of sockets, between the Arduino Nano and the Raspberry?

def reset_clock():
    print("reset the clock")
    time.sleep(10)
    NTP_DELTA = 2208988800
    host = b"pool.ntp.org"
    tz=-6 # Timezone Central Standard Time
    #tz=-5 # Timezone Central Daylight Time
    dst = 0

    NTP_QUERY = bytearray(48)
    NTP_QUERY[0] = 0x1B
    wlan.active(True)
    wlan.connect(ssid, password)

    max_wait = 10
    while max_wait > 0:
        print("wlan status= ",wlan.status()) # Debugging
#        if wlan.status() < 0 or wlan.status() >= 3:
        if wlan.status() == True:
            break
        max_wait -= 1
        print('waiting for connection...')
        time.sleep(1)

    if wlan.status() != True:
        raise RuntimeError('network connection failed')
    else:
        print('connected')
        status = wlan.ifconfig()
        print( 'ip = ' + status[0] )
        led.on()
    time.sleep(10)
#    addr = socket.getaddrinfo(host, 123)[0][-1]
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        addr = socket.getaddrinfo(host, 123)[0][-1]     # <---- fails here
        print("NTP addr = ",addr)                                    # <---- addr is not defined

#    except OSError as e:
    except:
        print(f"OS Error ")
#    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    print(s)

    try:
        s.settimeout(1)
        print("NTP addr = ",addr)
        res = s.sendto(NTP_QUERY, addr)
        msg = s.recv(48)
    finally:
        s.close()
    nina_rgb.ninapin_digital_write(nina_rgb.LEDR, 1)
    blue_led.on()
    
    val = struct.unpack("!I", msg[40:44])[0]
    t = val - NTP_DELTA + (tz + dst) * 3600  
    tm = time.gmtime(t)
    print("gm time=",t)
    machine.RTC().datetime((tm[0], tm[1], tm[2], tm[6] + 1, tm[3], tm[4], tm[5], 0))
    print("Time set")

    print(time.localtime())
    now = time.localtime()
    print("Date: {}/{}/{}".format(now[1], now[2], now[0]))
    print("Time: {}:{:02}".format(now[3], now[4]))
    time.sleep(10)
    print(time.localtime())
    now = time.localtime()
    print("Date: {}/{}/{} {}:{:02}".format(now[1], now[2], now[0], now[3], now[4]))
    time.sleep(5)
    blue_led.off()
# end reset_clock

[beetlegigg]

As a result of your previous post on getting the nano rp2040 connect loaded with mp, and the helpful info provided in the post replies, I also got my old nano connects working again. So I had a go with one of my resurrected boards by putting my normal get ntp time that works on my pico's onto the nano, and it works ok. Its my bed time so I have not pondered over why your routine was not working, but I just post the code snippet so you may be able to work what may be be going on with your code. The ntp code is not mine but was copied from the @peterhinch repositories. So here it is, and I hope it helps.

# Adapted from official ntptime by Peter Hinch July 2022
# The main aim is portability:
# Detects host device's epoch and returns time relative to that.
# Basic approach to local time: add offset in hours relative to UTC.
# Timeouts return a time of 0. These happen: caller should check for this.
# Replace socket timeout with select.poll as per docs:
# http://docs.micropython.org/en/latest/library/socket.html#socket.socket.settimeout

"""
Get ntp time from fritz.box (router time server) or ntp server 
"""

import socket
import struct
import select
from machine import RTC
from time import gmtime

rtc = RTC()

# (date(2000, 1, 1) - date(1900, 1, 1)).days * 24*60*60
# (date(1970, 1, 1) - date(1900, 1, 1)).days * 24*60*60
NTP_DELTA = 3155673600 if gmtime(0)[0] == 2000 else 2208988800

#time_server = 'fritz.box'
time_server = b"pool.ntp.org"


def ntp_time(hrs_offset=0):  # Local time offset in hrs relative to UTC
    NTP_QUERY = bytearray(48)
    NTP_QUERY[0] = 0x1B
    try:
        addr = socket.getaddrinfo(time_server, 123)[0][-1]
    except OSError:
        return 0
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    poller = select.poll()
    poller.register(s, select.POLLIN)
    try:
        s.sendto(NTP_QUERY, addr)
        if poller.poll(1000):  # time in milliseconds
            msg = s.recv(48)
            val = struct.unpack("!I", msg[40:44])[0]  # Can return 0
            return max(val - NTP_DELTA + hrs_offset * 3600, 0)
    except OSError:
        pass  # LAN error
    finally:
        s.close()
    return 0  # Timeout or LAN error occurred

def set_rtc():
    if ntp_time() == 0:
        return False
    else:
        tm = localtime(ntp_time())
        # Monday to Sunday - 0 to 6 weekdays
        rtc.datetime((tm[0], tm[1], tm[2], tm[6] + 1, tm[3], tm[4], tm[5], 0))
        return True
    
    
if __name__ == '__main__':
    import time
    from time import sleep, localtime
    from secrets import SSID, PW
    import network

    # connect to WiFi
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    count = 1
    while not wlan.isconnected():
        print('connection tries',count)
        wlan.connect(SSID, PW)
        time.sleep(1)
        count += 1
        
    print('connected??', wlan.isconnected())
    print('wlan status', wlan.status()) 
    print( 'ip: ', wlan.ifconfig()[0] )

    # get time and set the RTC
    if set_rtc():
        pass
    else:
        raise Exception("Could not set RTC")
    
    print('localtime:    ',localtime())
    print('rtc.datetime: ',rtc.datetime())
    
    sleep(5)
    print('localtime:    ',localtime())
    print('rtc.datetime: ',rtc.datetime())
    

[ScooterKraig]

Thanks, Beetlegigg. That helps a lot. This runs "right out of the box" with both a Raspberry Pico and the Arduino Nano RP2040, with only a minor change for the ssid and password. "addr = socket.getaddrinfo(time_server, 123)[0][-1]" returns "addr" as it should. Now to find out why this code works and mine doesn't. FYI:

MPY: soft reboot
connection tries 1
connection tries 2
connected?? True
wlan status True
ip:  192.168.1.190
addr =  ('168.235.89.132', 123)
addr =  ('168.235.89.132', 123)
localtime:     (2026, 3, 8, 14, 3, 3, 6, 67)
rtc.datetime:  (2026, 3, 8, 6, 14, 3, 3, 0)
localtime:     (2026, 3, 8, 14, 3, 8, 6, 67)
rtc.datetime:  (2026, 3, 8, 6, 14, 3, 8, 0)

[ScooterKraig]

More FYI. Maybe this will help someone in the future. The "connect to WIFI" routine here in beetlegigg's reply is a lot cleaner than mine and seems to be the difference in making my "reset_clock" code work. The key is using "while not wlan.isconnected" instead of waiting for "wlan.status":

    # connect to WiFi
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    count = 1
    while not wlan.isconnected():
        print('connection tries',count)
        wlan.connect(ssid, password)
        time.sleep(1)
        count += 1

[scruss]

.isconnected() is the check method that seems to have been around the longest in MicroPython. I haven't had it return a false positive.

wlan.status() also doesn't return True. If you're going to use it, maybe better to check against one of the constants in the network module:

if wlan.status() != network.STAT_GOT_IP:
    # do fail stuff

[shariltumin]

You can also try the MicroPython library, ntptime.

import network
from config import wifi
import time, socket
import ntptime  # we use MicroPython lib - ntptime
from machine import RTC

rtc = RTC()

# connect to WIFI
SSID, PWD = wifi 
network.WLAN(network.AP_IF).active(False)
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(SSID, PWD)
while not wlan.isconnected():
   print('.', end='')
   time.sleep(1)
print('\nConnected!')

# set DNS
DNS = '1.1.1.1'
ip, nm, gw, dns = wlan.ifconfig()
wlan.ifconfig((ip, nm, gw, DNS))

def lookup(host):
    if not host: return
    try:
       hip = socket.getaddrinfo(host, 0)[0][-1]
       return(hip[0])
    except Exception as e:
       print('Err:', e)
       return None

def settime(ts, tout=5, tz=0): # ts=time server ip.
    ntptime.host = ts
    ntptime.timeout = tout

    try:
       ntptime.settime()
       yr, mo, dy, hr, mn, sc, wd, yd = time.localtime()
       # Monday to Sunday - 0 to 6 weekdays
       # year, month, day, weekday, hours, minutes, seconds, subseconds
       rtc.datetime((yr, mo, dy, wd, hr+tz, mn, sc, 0))
       return True
    except Exception as e:
       print('--', e)
       return False

retry_cnt = 5
timeout = 5 # secs
hosts = ('no.pool.ntp.org', # Norway
         'europe.pool.ntp.org',
         'pool.ntp.org',
         'time.google.com',
         'time.cloudflare.com',
         'time.aws.com',
         'time.windows.com',
         'time.apple.com')
ok = False

# Set localtime - OSLO
# UTC+1 (Winter/CET) and UTC+2 (Summer/CEST)
# Winter (Nov - March 28, 2026)
# Summer (March 29 - Oct 24, 2026)
offset = 1 # offset = 2 for summer

for host in hosts:
    if ok: break
    # Look-up
    ip = lookup(host)
    if ip:
       print(f'{host}: {ip}')
       for i in range(retry_cnt):
           ok = settime(ip, timeout, offset)
           if ok: break
#           time.sleep(5)
#    time.sleep(5)

if ok:
   # What is the date and time now
   yr, mo, dy, hr, mn, sc, wd, yd = time.localtime()
   print(f'{yr:04d}{mo:02d}{dy:02d} {hr:02d}:{mn:02d}:{sc:02d}')
else:
   print('Localtime not properly set')