I have added simple dhcp client code to current tcp/ip stack running on lpc1768. For testing purpose i connected lpc1768 to my laptops ethernet port. Also i have enabled internet[from wifi] sharing[to lan]. I am able to get dhcp ip and related configuration always.

Now to test this with the router i used following setup
Router[Dlink-DIR605L] <------> Switch[Dlink-DES1005C] <------> Laptop and LPC1768 board

LPC1768 never gets IP from router. Also i cannot see any packets from LPC1768 on wireshark[running on Laptop].

I dont know what is wrong with my setup or is router discarding dhcp discover packet sent from lpc1768, really dont know.

UPDATE: When monitoring LINK status visually[LED's] and in the code, i see that LINK is UP for very short time only then it goes DOWN. This happens when i connect lpc1768 directly to router.
But when i connect lpc1768 to laptop LINK goes UP and is STABLE.
LPC1768 is using AutoNegotiation.

  • What kind of Ethernet cable do you use – 2-pair or 4-pair; regular or crossover? – grawity Mar 3 '17 at 5:29
  • Tried with 4pair - regular and crossover. I think cable type doesnt matter if using auto negotiation with auto mdix – anishkumar Mar 3 '17 at 15:00

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