problem getting micropython loopback example working on PiPico and W5500

Question

I am trying to get the loopback example to work on the PiPico (RP2040) with W550 chip using micropython. I am able to setup an nic, and can ping the board. The problem starts when calling the accept() function of a socket. When calling accept(), the script hangs. I am using this version of the micropython firmware: rp2_w5500_20221111_v2.0.0.uf2. Any suggestions on what is wrong? Here is my code: import socket from machine import Pin,SPI import network import rp2 import time from sys import stdin, stdout def w5x00_init(): spi=SPI(0,2_000_000, mosi=Pin(19),miso=Pin(16),sck=Pin(18)) nic = network.WIZNET5K(spi,Pin(17),Pin(20)) #spi,cs,reset pin nic.active(True) nic.ifconfig(('192.168.5.120','255.255.255.0','192.168.5.1','8.8.8.8')) startTs = time.time() while not nic.isconnected(): time.sleep(1) if time.time() - startTs > 5: break return nic if nic.isconnected() else False def main(): nic = w5x00_init() if not nic: print('Problem connecting to network') return else: ip = nic.ifconfig()[0] print('IP address: ', ip) s = socket.socket() #socket.AF_INET, socket.SOCK_STREAM s.bind((ip, 5000)) s.listen(5) conn, addr = s.accept() # hangs on this line print("Connect to:", conn, "address:", addr) print("Loopback server Open!") while True: data = conn.recv(2048) print(data.decode('utf-8')) if data != 'NULL': conn.send(data) if __name__ == "__main__": main()

Eugeny · Answer

I suspect s = socket.socket() must have some arguments, supplied, at least W5500 socket number to open socket interface for?

Eugeny · Answer

Can you provide link to the sources you refer to? Is there any documentation for the library/calls provided? scottdky: What arguments should I try? There must be at least indication of the W5500 socket number, W5500 is having 8 of them. In the code I see you set up common registers, I see you open socket, set it to listen on port 5000, but I do no see which W5500 socket you a configuring.

scottdky · Answer

FYI, the Wiznet example code is here - RP2040-HAT-MicroPython/examples/Loopback at main · Wiznet/RP2040-HAT-MicroPython · GitHub But, I found the problem. In my ignorance, I didn’t understand what the socket.accept function did. After studying python (instead of micropython) documentation, I realized it was waiting for another computer to connect to it. When I did so, the function call returned as expected. I apologize for the newbie mistake. Also FYI, according to python documentation, s = socket.socket() does default to socket.AF_INET, socket.SOCK_STREAM.