Arduino uno User Manual

we use the service programmatically with an Arduino, see how it works using
the telnet command:
maik> telnet time.nist.gov 13
Trying 192.43.244.18...
Connected to time.nist.gov.
Escape character is '^]'.
56965 14-11-04 20:33:03 00 0 0 867.4 UTC(NIST) *
Connection closed by foreign host.
As soon as the telnet command connects to the Daytime server, it sends back
the current time and date.
10
Then the service shuts down the connection
immediately.
Here’s an implementation of exactly the same behavior for an Arduino with
an Ethernet shield:
Ethernet/TimeServer/TimeServer.ino
#include <SPI.h>
Line 1
#include <Ethernet.h>
-
const unsigned int BAUD_RATE = 9600;
-
const unsigned int DAYTIME_PORT = 13;
-
5
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
-
IPAddress my_ip(192, 168, 2, 120);
-
IPAddress time_server(192, 43, 244, 18); // time.nist.gov
-
EthernetClient client;
-
10
void setup() {
-
Serial.begin(BAUD_RATE);
-
Ethernet.begin(mac, my_ip);
-
}
-
15
void loop() {
-
delay(1000);
-
Serial.print("Connecting...");
-
-
if (client.connect(time_server, DAYTIME_PORT) <= 0) {
20
Serial.println("connection failed.");
-
} else {
-
Serial.println("connected.");
-
delay(300);
-
while (client.available()) {
25
char c = client.read();
-
Serial.print(c);
-
}
-
-
10. See http://www.nist.gov/physlab/div847/grp40/its.cfm for a detailed description of the date string’s
format.
Chapter 10. Networking with Arduino • 174
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Arduino uno Specifications

General

Form factor	Arduino
Certification	RoHS, FC, CE
Processor model	-
Processor frequency	- MHz
Microcontroller model	ATmega328
Microcontroller frequency	16 MHz
DC input voltage	7-12 V
Operating voltage	5 V
DC current per I/O pin	40 mA
Flash memory	0.032 MB
Maximum internal memory	- GB
SRAM (Static Random Access Memory)	2 KB
EEPROM (Electrically Erasable Programmable Read-Only Memory)	1 KB
Wi-Fi	No
Number of analog I/O pins	6
Number of digital I/O pins	14

Weight and Dimensions

Board dimensions	53.4 x 68.6 mm