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Description
Hello,
I am using Portenta H7 + vision shield, and I set up the codes to receive UDP multicast data. The codes compiled but I'm not receiving any data. Can someone help to clarify if Udp multicast is possible on Portenta H7 and vision shield? Or if I am missing something in the codes?
Arduino IDE version 1.8.19
Arduino Mbed OS Portenta Boards, version 3.5.4
Below is my codes on the Arduino as UDP Multicast Receiver, static ip: 195.0.0.92
#include <PortentaEthernet.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#ifndef UDP_TX_PACKET_MAX_SIZE
#define UDP_TX_PACKET_MAX_SIZE 24
#endif
EthernetUDP Udp;
IPAddress ip(195,0,0,92);
unsigned int localPort = 1234;
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
char replyBuffer[] = "acknowledged";
void setup() {
Serial.begin(9600);
while (!Serial) {};
Ethernet.begin(ip);
if (Udp.beginMulticast(IPAddress(239,1,2,3), 1234)) {
Serial.println("Connected multicast");
}
Serial.begin(9600);
}
void loop() {
int packetSize = Udp.parsePacket();
if (packetSize) {
Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
Serial.println("Contents:");
Serial.println(packetBuffer);
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(replyBuffer);
Udp.endPacket();
}
delay(10);
}
On the UDP Multicast Sender, here is my code in Python running from my laptop, static ip 195.0.0.91
import socket
import struct
import sys
message = 'very important data'
multicast_group = ('239.1.2.3', 1234)
# Create the datagram socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# Set a timeout so the socket does not block indefinitely when trying
# to receive data.
sock.settimeout(0.2)
# Set the time-to-live for messages to 1 so they do not go past the
# local network segment.
ttl = struct.pack('b', 1)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
try:
# Send data to the multicast group
print >>sys.stderr, 'sending "%s"' % message
sent = sock.sendto(message, multicast_group)
# Look for responses from all recipients
while True:
print >>sys.stderr, 'waiting to receive'
try:
data, server = sock.recvfrom(16)
except socket.timeout:
print >>sys.stderr, 'timed out, no more responses'
break
else:
print >>sys.stderr, 'received "%s" from %s' % (data, server)
finally:
print >>sys.stderr, 'closing socket'
sock.close()
To further clarify, I could ping Portenta (195.0.0.92) from my laptop (195.0.0.91) after upload the codes to Portenta. I also verified the multicast sender working by reading multicast data from a 2nd laptop with the below Python codes:
import socket
import struct
UDP_PORT = 1234
MYGROUP_4 = '239.1.2.3'
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
mreq = struct.pack("4sl", socket.inet_aton(MYGROUP_4), socket.INADDR_ANY)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
sock.settimeout(5.0)
sock.bind((MYGROUP_4, UDP_PORT))
while True:
try:
data, addr = sock.recvfrom(1024)
print(addr, data)
except socket.timeout:
print("timeout")