Issue with W5500 hardware interrupt

Question

I need to catch incoming TCP packets by interruption. I have implemeneted following : In the loop, I invoke the register check procedure Sn_IR (Sn_IMR = 0x1F); If the RECV = 1 bit in the Sn_IR register, at the first I call a procedure for reading the packet and after the procedure for sending the response packet; After reading a packet and sending the response, the Sn_IR register automatically resets to 0x00; That’s how it works. Now, If I turn on the hardware interrupt, I have did following: Chip initialization procedure sets the register SIMR = 0xFF (although only one socket is used); Interrupt procedure check the RECV bit in the Sn_IR register. If bit RECV = 1 then set the flag FL_INT_RECV and leave the interrupt; In the loop: A procedure of flag FL_INT_RECV verification invokes. If the flag is set, then a procedure calls for reading the packet, sending the response packet and reset flag by resetting the interrupt bits: setSIR (0x00); setSn_IR (SOCK_TCP, 0x1F); In doing so, I receive one packet and can send one response only. The INT line stays low (SIR != 0x00, Sn_IR != 0x00). What I am doing wrong? Please, I will be thankful for any suggestions. Thank!

becky · Answer

I recommend you set Sn_IMR to 0x04. If so, the interrupt occurs only when it is recv, so there is no need to check if it is a recv interrupt when the interrupt occurs. setSIR (0x00) is meaningless. SIR is automatically cleared according to Sn_IR. If you did setSn_IR (SOCK_TCP, 0x1F), the interrupt is cleared and the INT line should go high. If setSn_IMR (0xff) is set and you set setSn_IR (SOCK_TCP, 0x1F) in recv only, interrupts may occur in other bits and thus may not be cleared. This can be solved by setting 0x04 in sn_imr.