RCV interrupt high but buffer len is 0

Question

I am getting interrupt status for socket that bytes are received, but when I try to read sockets receive size register, its value is 0. Do I need to send command Receive before reading the register or this register will have size immediately after getting interrupt ? Thanks

Eugeny · Answer

Don’t you forget to reset this interrupt flag bit in your ISR? If you will not reset it manually W5100 will continue holding interrupt line active.

gossamer · Answer

So, I am polling the value of interrupt on common Reg Address (0x0015) and checking which socket received interrupt. Then I read value of interrupt on socket reg address, and checking if RECV bit is set. if it is set, I am clearing a bit by writing (1<<2) on interrupt register. And after that I read rx received size register 0x0*26 (0x0426 for socket 0). But I always read 0, even though I sent the character. I dont have pending interrupt after that, cause recv bit is reset, until next char of course. So, apart from actual reading of buffer, interrupts are working properly Edit Found the bug … totally retarded one. I was actually reading socket1 instead of socket0 It is working now, at least the size of buffer, now I need to do the actual reading, but I have feeling it should be the same as sending something …