10 years, 3 months ago.

Cold start vs. reset on LPC4088 using LWIP

I'm using the LPC4088 Quickstart board running mbed and LWIP. I've configured the ethernet i/f to use DHCP and it initializes (calls eth.init()) at boot up but does not call the eth.connect() method until it is invoked from the command line.

I've noticed that on a cold start this always works. I get a connected interface complete with IP address and it is usable.

Over time as I work with this platform eventually it will hang on a reset. It goes right to the hard fault handler when the connect() method is called and happens after the NVIC turns on the interrupt for the ethernet interface. From this moment on a reset will not correct the problem. However, if I do a cold start then the problem is corrected and I have a working ethernet i/f.

Is it possible that there is some kind of persistent information in the MAC that is not being cleared by the reset but is being cleared when power is removed from the device? Or perhaps someone else has an idea or has seen this problem.

Cheers!!