The connection between WIZ810MJ and microcontroller has been estatablised using SPI. Writing and reading back data to and from first 16 bytes is OK. The only one LED, Right LED on MAG-jack, is on in amber. There is no response when the PC tries to ping to WIZ810MJ. Please would you suggest me. The second thing is what the function of the two LED on MAG-jack is?
You mean the SPI, after the first 16bytes, you cannot read or write anymore??
Then please check the SPI register settings especially about SPI buffer.
And the two LEDs on MACJACK, one of them is link LED (link and act status) and another one is FDX LED (full duplex status).
So if you use full-duplex one LED is always on and another LED is blinking when it has RX/TX communication.
Anyway, since the echo reply packet (ping test) is generated by H/W logic of W5100, if you cannot receive the echo reply packet from WIZ810MJ, the W5100 was not successfully configured (register settings and RD/WR bus).
Please check the SPI communication, register settings and reset signal to W5100.