WIZnet Developer Forum

WIZ105SR Can not configure via serial while DHCP request is pending

I am unable to access the serial configuration while a DHCP request is pending. This is a problem as a user, who is connected to my device via serial, is unable to switch to a static IP in the case of no DHCP. How can I solve this?

If you can input serial commands on the UART port, then you can change its IP address acquisition method with one of serial commands.
Can you do this?

That is currently my problem. The WIZ105SR does not respond to the +++ command while waiting for DHCP.

I checked the firmware of WIZ105SR and found out that we can’t intercept the control of MCU before DHCP process finishes.
It might take a quite long time to change this logic to make it accept user’s command from Ethernet or Serial while DHCP process is running.

We, WIZnet, have another module the form factor of which is the same as WIZ105SR. So we call it WIZ750SR-105 and it can be handled with user’s commands while DHCP running because it has different code structure.
Can you use WIZ750SR-105 instead of the old one?


Thanks James. I’ve ordered the other module and will evaluate it for our application.