I am using the W7500S2E-R1 module and configured as TCP client in DHCP mode.
W7500S2E-R1 is connected to a Desktop using Serial Interface and the other end (Ethernet) is connected to 3G Router (transfers data via cellular network using SIM card). The Desktop is running teraterm to input data & display incoming data on screen and is configured correctly. (Default settings - Baud Rate: 115,200, data size: 8, Parity: None, stop bit: 1 and Flow control: None).
I sent a HTTP request from teraterm and get HTTP response from Wiznet module. But, in some instances it fails to receive HTTP response back from Wiznet module. The very next HTTP request will get a HTTP response successfully. I have attached both the teraterm & the relevant Wireshark logs. When checking the Wireshark log, I found that the HTTP response actually reaches the LAN interface but not the serial interface. Deeper analysis shows that any response that comes after the 0.8 secs from HTTP request sent time , is ignored by wiznet module and doesn’t get passed to serial interface. Instead, the wiznet module assumes the socket is lost and send another SYN packet to server. Below is one of the sample for no-response,
At no 89, HTTP request (port no: 5006) is been made; after 3 re-transmission of data, finally the response reached the LAN interface at 93; soon after a SYN packet is sent to the server with new port number 5007. Meanwhile, the response doesn’t get reached to serial interface, which is evident in the teraterm log I attached (at the same time 2021-02-16 15:02:50). Same instance happened in last request at 2021-02-16 15:05:39. Is there any internal response timeout that causing this issue. However I have disabled the available wiznet timers (Inactivity Time, Keep Alive Time - set to zero).
Can anyone help how to recover?
Thanks in advance.
Note: teraterm and Wireshark logs are edited to hide confidential infos. This problem never exists with LAN or 4G router.
logs.zip (4.3 KB)