lpcware

lpc1788+lan8720 Ethernet FCS calculation

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by padmaja on Thu Feb 25 02:11:57 MST 2016
hi,
i am using uezgui-1788-70wvm module.

1.in this i want to calculate FCS, i was used simple c program provide in UM10470 user maual. But if i generate FCS using this function,wireshark shows wrong checksum. i was tried with different crc-32 formats, wire shark shows all are wrong. Let me know, if is there any specific protocol is there for FCS calculation??

2. if i reply to ARP request from other module i just send 42 bytes arp reply message, but it is not appear at wireshark at the same time its not reached to host. i was tried to send 60bytes msg also then also same behaviour. If i send ARP reply to my pc, at this time ethernet frame (arp reply ) is appear in wireshark. Is there any specific reason for this behaviour? or i was missing something in firmware of lpc1788??

thanks & regards,
padmaja.

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