Class WiFiUdp
WiFiUDP Class
Description
Defines a class of WiFi UDP implementation for Ameba.
Members
Public Constructors |
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WiFiUDP::WiFiUDP |
Constructs a WiFiUDP instance of the
WiFi UDP class that can send and
receive UDP messages |
Public Methods |
|
WiFiUDP:: begin |
initialize, start listening on the
specified port. Returns 1 if
successful, 0 if there are no sockets
available to use |
WiFiUDP:: stop |
Finish with the UDP socket |
WiFiUDP:: beginPacket |
Start building up a packet to send to
the remote host-specific in IP and
port |
WiFiUDP:: endPacket |
Finish off this packet and send it |
WiFiUDP:: write |
Write a single byte into the packet |
WiFiUDP:: writeImmediately |
Send packet immediately from the
buffer |
WiFiUDP:: parsePacket |
Start processing the next available
incoming packet |
WiFiUDP::available |
Number of bytes remaining in the
current packet |
WiFiUDP::read |
Read a single byte from the current
packet |
WiFiUDP:: peek |
Return the next byte from the current
packet without moving on to the next
byte |
WiFiUDP:: flush |
Finish reading the current packet |
WiFiUDP:: remoteIP |
Return the IP address of the host who
sent the current incoming packet |
WiFiUDP:: remotePort |
Return the port of the host who sent
the current incoming packet |
WiFiUDP:: setRecvTimeout |
Set receiving timeout |
WiFiUDP::WiFiUDP
Description
Constructs a WiFiUDP instance of the WiFi UDP class that can send and
receive UDP messages.
Syntax
WiFiUDP::WiFiUDP(void)
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort.
#include <WiFi.h>
#include <WiFiUdp.h>
int status = WL_IDLE_STATUS;
char ssid[] = “yourNetwork”; // your network SSID (name)
char pass[] = “secretPassword”; // your network password (use for
WPA, or use as key for WEP)
int keyIndex = 0; // your network key Index number (needed only for
WEP)
unsigned int localPort = 2390; // local port to listen on
char packetBuffer[255]; //buffer to hold incoming packet
char ReplyBuffer[] = “acknowledged”; // a string to send back
WiFiUDP Udp;
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println(“WiFi shield not present”);
// don’t continue:
while (true);
}
String fv = WiFi.firmwareVersion();
if (fv != “1.1.0”) {
Serial.println(“Please upgrade the firmware”);
}
// attempt to connect to Wifi network:
while (status != WL_CONNECTED) {
Serial.print(“Attempting to connect to SSID: “);
Serial.println(ssid);
// Connect to WPA/WPA2 network. Change this line if using open or WEP
network:
status = WiFi.begin(ssid,pass);
// wait 10 seconds for connection:
delay(10000);
}
Serial.println(“Connected to wifi”);
printWifiStatus();
Serial.println(”nStarting connection to server…”);
// if you get a connection, report back via serial:
Udp.begin(localPort);
}
void loop() {
// if there’s data available, read a packet
int packetSize = Udp.parsePacket();
if (packetSize) {
Serial.print(“Received packet of size “);
Serial.println(packetSize);
Serial.print(“From “);
IPAddress remoteIp = Udp.remoteIP();
Serial.print(remoteIp);
Serial.print(”, port “);
Serial.println(Udp.remotePort());
// read the packet into packetBufffer
int len = Udp.read(packetBuffer, 255);
if (len > 0) {
packetBuffer[len] = 0;
}
Serial.println(“Contents:”);
Serial.println(packetBuffer);
// send a reply, to the IP address and port that sent us the packet we
received
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}
}
void printWifiStatus() {
// print the SSID of the network you’re attached to:
Serial.print(“SSID: “);
Serial.println(WiFi.SSID());
// print your WiFi shield’s IP address:
IPAddress ip = WiFi.localIP();
Serial.print(“IP Address: “);
Serial.println(ip);
// print the received signal strength:
long rssi = WiFi.RSSI();
Serial.print(“signal strength (RSSI):”);
Serial.print(rssi);
Serial.println(” dBm”);
}
Notes and Warnings
This constructor does not take in any parameter, thus use another
method to set up the IP address and port number.
WiFiUDP::begin
Description
Initialize, start listening on the specified port. Returns 1 if
successful, 0 if there are no sockets available to use.
Syntax
uint8_t WiFiUDP::begin(uint16_t port)
Parameters
port: the local port to listen on
Returns
1: if successful
0: if there are no sockets available to use
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::stop
Description
Disconnect from the server. Release any resource being used during the
UDP session.
Syntax
void WiFiUDP::stop(void)
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
WiFiUDP::beginPacket
Description
Start building up a packet to send to the remote host-specific in IP
and port.
Syntax
int WiFiUDP::beginPacket(const char *host, uint16_t port)
int WiFiUDP::beginPacket(IPAddress ip, uint16_t port)
Parameters
host: hostname
port: port number
ip: IP address
Returns
1: if successful
0: if there was a problem with the supplied IP address or port
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::endPacket
Description
Finish off this packet and send it
Syntax
int WiFiUDP::endPacket(void)
Parameters
The function requires no input parameter.
Returns
1: if the packet was sent successfully
0: if there was an error
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::write
Description
Write a single byte into the packet.
Syntax
size_t WiFiUDP::write(uint8_t byte)
size_t WiFiUDP::write(const uint8_t *buffer, size_t size)
Parameters
byte: the outgoing byte
buffer: the outgoing message
size: the size of the buffer
Returns
single-byte into the packet
bytes size from the buffer into the packet
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::writeImmediately
Description
Send packet immediately from the buffer
Syntax
size_t WiFiUDP::writeImmediately(const uint8_t *buffer, size_t size)
Parameters
buffer: the outgoing message
size: the size of the buffer
Returns
single-byte into the packet
bytes size from the buffer into the packet
WiFiUDP::parsePacket
Description
Start processing the next available incoming packet
Syntax
int WiFiUDP::parsePacket(void)
Parameters
The function requires no input parameter.
Returns
The function returns the size of the packet in bytes or returns “0:”
if no packets are available.
Example Code
Example: WiFiUdpSendReceiveString
WiFiUDP::available
Description
Number of bytes remaining in the current packet.
Syntax
int WiFiUDP::available(void)
Parameters
The function requires no input parameter.
Returns
the number of bytes available in the current packet
0: if parsePacket hasn’t been called yet
WiFiUDP::read
Description
Read a single byte from the current packet
Syntax
int WiFiUDP::read()
int WiFiUDP::read(unsigned char* buffer, size_t len)
Parameters
buffer: buffer to hold incoming packets (char*)
len: maximum size of the buffer (int)
Returns
size: the size of the buffer
-1: if no buffer is available
Example Code
Example: WiFiUdpSendReceiveString
his example demonstrates WiFi UDP send and receive string. This sketch
waits for a UDP packet on a local port using a WiFi shield. When a
packet is received an Acknowledge packet is sent to the client on port
remotePort. The detail of the code can be found in WiFiUDP:: WiFiUDP.
WiFiUDP::peek
Description
Return the next byte from the current packet without moving on to the
next byte
Syntax
int WiFiUDP::peek(void)
Parameters
The function requires no input parameter.
Returns
b: the next byte or character
-1: if none is available
WiFiUDP::flush
Description
Finish reading the current packet
Syntax
void WiFiUDP::flush(void)
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
WiFiUDP::remoteIP
Description
Return the IP address of the host who sent the current incoming packet
Syntax
IPAddress WiFiUDP::remoteIP(void)
Parameters
The function requires no input parameter.
Returns
IP address connecting to
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::remotePort
Description
Return the port of the host who sent the current incoming packet
Syntax
uint16_t WiFiUDP::remotePort(void)
Parameters
The function requires no input parameter.
Returns
The remote port connecting to
Example Code
Example: WiFiUdpSendReceiveString
This example demonstrates WiFi UDP send and receive string. This
sketch waits for a UDP packet on a local port using a WiFi shield.
When a packet is received an Acknowledge packet is sent to the client
on port remotePort. The detail of the code can be found in WiFiUDP::
WiFiUDP.
WiFiUDP::setRecvTimeout
Description
Set receiving timeout
Syntax
void WiFiUDP::setRecvTimeout(int timeout)
Parameters
timeout in seconds
Returns
The function returns nothing.