Deepika Bhavnani
UDP Socket application to read current time from network.
This is an UDP example to read current UTC time by sending request to NIST Internet Time Service.
Revision 0:b90f9dc5cf9c, committed 2017-10-18
- Comitter:
- deepikabhavnani
- Date:
- Wed Oct 18 21:59:15 2017 +0000
- Commit message:
- UDP Socket Sample
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/.gitignore Wed Oct 18 21:59:15 2017 +0000 @@ -0,0 +1,4 @@ +.build +.mbed +projectfiles +*.py*
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/README.md Wed Oct 18 21:59:15 2017 +0000 @@ -0,0 +1,8 @@ +### Getting started with the UDPSocket API ### + +UDP Example +This application reads the current UTC time by sending UDP packet to time.nist.gov address at port 37. + +**Note:** The current example is limited to the ethernet interface on supported devices. +To use the example with a different interface, you will need to modify main.cpp and +replace the EthernetInterface class with the appropriate interface.
Binary file img/uvision.png has changed
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Wed Oct 18 21:59:15 2017 +0000
@@ -0,0 +1,46 @@
+#include "mbed.h"
+#include "EthernetInterface.h"
+
+// Network interface
+EthernetInterface net;
+
+// Time protocol implementation : Address: time.nist.gov UDPPort: 37
+
+typedef struct {
+ uint32_t secs; // Transmit Time-stamp seconds.
+}ntp_packet;
+
+int main() {
+ // Bring up the ethernet interface
+ printf("UDP Socket example\n");
+ if(0 != net.connect()) {
+ printf("Error connecting\n");
+ return -1;
+ }
+
+ // Show the network address
+ const char *ip = net.get_ip_address();
+ printf("IP address is: %s\n", ip ? ip : "No IP");
+
+ UDPSocket sock(&net);
+ SocketAddress sockAddr;
+
+ char out_buffer[] = "time";
+ if(0 > sock.sendto("time.nist.gov", 37, out_buffer, sizeof(out_buffer))) {
+ printf("Error sending data\n");
+ return -1;
+ }
+
+ ntp_packet in_data;
+ int n = sock.recvfrom(&sockAddr, &in_data, sizeof(ntp_packet));
+ in_data.secs = ntohl( in_data.secs ) - 2208988800; // 1900-1970
+ printf("Time Received %lu seconds since 1/01/1900 00:00 GMT\n", (uint32_t)in_data.secs);
+ printf("Time = %s", ctime(( const time_t* )&in_data.secs));
+
+ printf("Time Server Address: %s Port: %d\n\r", sockAddr.get_ip_address(), sockAddr.get_port());
+
+ // Close the socket and bring down the network interface
+ sock.close();
+ net.disconnect();
+ return 0;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-os.lib Wed Oct 18 21:59:15 2017 +0000 @@ -0,0 +1,1 @@ +https://github.com/ARMmbed/mbed-os/#6e0d01cd13e8aca7bf4d697c3699ec9225386881