I also am trying to get a multicast application running on the F91 evaluation board (trying to read a multicast stream from the network) but cannot get any multicast data through the zilog system. I am performing an IGMP Join command but I'm guessing nothing is getting past the MAC. The thread below (about raw socket programming) didn't seem to help. Any thoughts? (Be gentle - I'm not a real softy!!!)

Just some initial thoughts -

Did you initialize the IGMP at startup with the command:
INT16 hginit(UINT8 iface)

Verify the multicast address you sent to the hgjoin is the address the application is using and that the proper interface was sent. You will have to call hgjoin for every multicast address you are wanting to receive.

Only multicast addresses in the range 224.0.0.2 to 239.255.255.255
must be used. Broadcast IP addresses cannot be used with this protocol.
All IP multicast addresses are Class D IPv4 addresses (i.e., the first four
bits are 1110).

Multicasting on the network is limited to the local network
if a multicast router is not present on the local network.

Thanks for the reply Tom.

I have used the TCPUDPDemo sample as my starting point. In the ZTPAppEntry(void) routine I have added hginit(0); and hgjoin (0,name2ip("239.255.0.1"),10); - the address of the multicast I'm trying to access is 239.255.0.1. Not sure what value I should be using for the last TTL parameter! I have also tried the igmp 0 join 235..... command line command.

Using the BSDUDPSERVER command I can prove that the unit receives unicast messages. Monitoring the PC that the unit is directly connected to I can also see the multicast messages coming out. But, breaking into the RxFunc(void) routine I am not getting any Ethernet frames containing multicast data.

Note: I do not see any IGMP messages come OUT of the Zilog when I issue the hgjoin command. Should I? I am wondering if somewhere the MAC is set up to discard multicast/igmp. Is this possible?

Thanks again, Tim.

Tim
Thank you for the clarification.

Please check the Project Setttings->Objects and Libraries
In the additional Library box, scroll through and look for the stub:
noigmp.obj
This is a stub to disable igmp.
You will want to remove this and rebuild the project
Let me know if IGMP starts working.

Tom,
That's it - working! Wonderful! Wonderful!! Wonderful!!!
I'm very grateful for your help - excellent