problem solved.
to OPEN socket 2 in IPRAW mode, first i must set the S2_MR protocol (P3:P2:P1:P0) to 0011 (0x03) which is IPRAW mode (you did not write it in your datasheet, i wonder why?) and then sent OPEN command to S2_CR.
after the S2_SR status changed to 0x32 (SOCK_IPRAW), i have successfully sent PING message and got reply.
Good Job!
Thank you for your interesting on WIZnet chips.
