AceTime  1.7.2
Date and time classes for Arduino that support timezones from the TZ Database, and a system clock that can synchronize from an NTP server or an RTC chip.
Public Member Functions | Static Public Attributes | List of all members
ace_time::clock::NtpClock Class Reference

A Clock that retrieves the time from an NTP server. More...

#include <NtpClock.h>

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Public Member Functions

 NtpClock (const char *server=kNtpServerName, uint16_t localPort=kLocalPort, uint16_t requestTimeout=kRequestTimeout)
 Constructor. More...
 
void setup (const char *ssid=nullptr, const char *password=nullptr, uint16_t connectTimeoutMillis=kConnectTimeoutMillis)
 Set up the WiFi connection using the given ssid and password, and prepare the UDP connection. More...
 
const char * getServer () const
 Return the name of the NTP server.
 
bool isSetup () const
 Return true if setup() suceeded.
 
acetime_t getNow () const override
 Return the number of seconds since the AceTime epoch (2000-01-01T00:00:00Z). More...
 
void sendRequest () const override
 Send a time request asynchronously.
 
bool isResponseReady () const override
 Return true if a response is ready.
 
acetime_t readResponse () const override
 Returns number of seconds since AceTime epoch (2000-01-01). More...
 
- Public Member Functions inherited from ace_time::clock::Clock
 Clock ()=default
 Default constructor.
 
 ~Clock ()=default
 We deliberately avoid using a virtual destructor. More...
 
virtual void setNow (acetime_t)
 Set the time to the indicated seconds. More...
 

Static Public Attributes

static const char kNtpServerName [] = "us.pool.ntp.org"
 Default NTP Server.
 
static const uint16_t kLocalPort = 2390
 Default port used for UDP packets.
 
static const uint16_t kRequestTimeout = 1000
 Request time out milliseconds.
 
- Static Public Attributes inherited from ace_time::clock::Clock
static const acetime_t kInvalidSeconds = LocalTime::kInvalidSeconds
 Error value returned by getNow() and other methods when this object is not yet initialized.
 

Detailed Description

A Clock that retrieves the time from an NTP server.

This class has the deficiency that the DNS name resolver WiFi.hostByName() is a blocking call. So every now and then, it can take 5-6 seconds for the call to return, blocking everything (e.g. display refresh, button clicks) until it times out.

TODO: Create a version that uses a non-blocking DNS look up.

Warning: If you are using an ESP8266, AND you are using the analogRead() function, calling analogRead() too quickly will cause the WiFi connection to disconnect after 5-10 seconds. Calling NtpClock::setup() will not fix the disconnect. See https://github.com/esp8266/Arduino/issues/1634 and https://github.com/esp8266/Arduino/issues/5083. The solution is to add a slightly delay between calls to analogRead(). I don't know what the minimum value should be, but using a 10ms delay seems to work for me.

Borrowed from https://github.com/esp8266/Arduino/blob/master/libraries/ESP8266WiFi/examples/NTPClient/NTPClient.ino and https://github.com/PaulStoffregen/Time/blob/master/examples/TimeNTP/TimeNTP.ino

Definition at line 48 of file NtpClock.h.

Constructor & Destructor Documentation

◆ NtpClock()

ace_time::clock::NtpClock::NtpClock ( const char *  server = kNtpServerName,
uint16_t  localPort = kLocalPort,
uint16_t  requestTimeout = kRequestTimeout 
)
inlineexplicit

Constructor.

Parameters
servername of the NTP server (default us.pool.ntp.org)
localPortused by the UDP client (default 8888)
requestTimeoutmilliseconds for a request timeout (default 1000)

Definition at line 65 of file NtpClock.h.

Member Function Documentation

◆ getNow()

acetime_t ace_time::clock::NtpClock::getNow ( ) const
overridevirtual

Return the number of seconds since the AceTime epoch (2000-01-01T00:00:00Z).

Returns kInvalidSeconds if an error has occured.

This is a blocking call. Some clocks (e.g. NTP client) this may take many seconds. On those clocks, use the asynchronous methods (sendRequest(), isResponseReady(), and readResponse()) instead.

Implements ace_time::clock::Clock.

Definition at line 55 of file NtpClock.cpp.

◆ readResponse()

acetime_t ace_time::clock::NtpClock::readResponse ( ) const
overridevirtual

Returns number of seconds since AceTime epoch (2000-01-01).

Return kInvalidSeconds if there is an error. Valid only if isResponseReady() returns true.

Reimplemented from ace_time::clock::Clock.

Definition at line 121 of file NtpClock.cpp.

◆ setup()

void ace_time::clock::NtpClock::setup ( const char *  ssid = nullptr,
const char *  password = nullptr,
uint16_t  connectTimeoutMillis = kConnectTimeoutMillis 
)

Set up the WiFi connection using the given ssid and password, and prepare the UDP connection.

If the WiFi connection was set up elsewhere, you can call the method with no arguments to bypass the WiFi setup.

Parameters
serverwireless SSID (default nullptr)
passwordpassword of the SSID (default nullptr)
connectTimeoutMillishow long to wait for a WiFi connection (default 10000 ms)

Definition at line 18 of file NtpClock.cpp.


The documentation for this class was generated from the following files: