WIZ550io Ver1.3 using MPLab X IDE v6.0 and Wiznet_DHCP project with iolibrary

Question

Hello, I am trying to evaluate WIZ550io board for use in a simple Ethernet bridge as a Telnet server. The easiest interface I had was a PIC32 eval board and I wired up the SPI interface as needed. I came across a Wiznet_DHCP project with ioLibrary for MPLab. With minor mods and running in MPLab X v6.0 the DHCP is defaulting to static IP which is fine and once socket is established, all is working. The one issue is that the code goes into a while loop when socket is listening // Delay for 1ms for the connection process while ((sockStatus = getSn_SR(DATASOCKET)) == SOCK_LISTEN) { tmp = 0xFFFF; while (tmp--); } Once SOCK_ESTABLISHED, fall out of loop and connected! I don't want to stay in this loop and added timer to check getSn_SR register for SOCK_ESTABLISHED. It never works!!! How often or how fast do I need to check? Is there an interrupt? Does it time out if I don't follow up with something when request comes in?

Grace_Koo · Answer

Hello, I’d like to provide a follow-up with additional details to complement the previous answer. If you want to avoid a while(getSn_SR() == SOCK_LISTEN) style of polling, you can use the INTn interrupt pin of the WIZ550io to handle connection events asynchronously. This allows your MCU to react only when needed, avoiding busy loops and saving CPU resources. By connecting the INTn pin to the external interrupt input of your MCU (typically configured for falling-edge), the MCU can detect the event and respond by checking the appropriate interrupt registers. Reference: W5500 Datasheet, Page 56: Interrupt Mask Register (Sn_IMR (Socket n Interrupt Mask Register) [R/W] [0x002C] [0xFF]) W5500 Datasheet, Page 48: Socket n Interrupt Register (Sn_IR (Socket n Interrupt Register) [RCW1] [0x0002] [0x00]) Basic Workflow Open a socket and call listen(). Enable the connection interrupt in the Sn_IMR register for the target socket. Set up an external interrupt on the MCU connected to the W5500’s INTn pin. When the INTn signal goes low, the MCU interrupt handler should read the Sn_IR register, check for the Sn_IR_CON bit, and handle the connection event. Clear the interrupt flag by writing 1 back to the corresponding bit in Sn_IR. Example Code // Enable connection interrupt for the socket setSn_IMR(DATASOCKET, getSn_IMR(DATASOCKET) | Sn_IR_CON); // In the main loop — do not block if (getSn_SR(DATASOCKET) == SOCK_LISTEN) { // Socket is listening, waiting for peer connection // The interrupt will notify when connected } // Interrupt handler (called when INTn is triggered) void wiznet_irq_handler(void) { uint8_t sn_ir = getSn_IR(DATASOCKET); if (sn_ir & Sn_IR_CON) { // Connection established // Proceed with connection handling here } // Clear interrupt flag setSn_IR(DATASOCKET, sn_ir); } Notes INTn is active-low, so configure the MCU interrupt for falling-edge detection. The Sn_IMR register must have the corresponding bit enabled to allow the interrupt to occur. Interrupt flags in…