hi i have lpc1768 with DP83848CVV as phy. when im in debug mode its work fine but when im reseting my board without debug attach to it it does not work. everything work but Ethernet. same issue here www.lpcware.com/.../software-runs-some-peripherals-doesnt-when-target-started-without-jtagswd
in issue above they solve the problem but i dont get it how they did it
Make sure you have enabled all AHB/APB clocks you peripherals need, the debugger may have enabled things for itself. Check timing critical loops. Consider using a UART to output debugging and diagnostic information. Dump out clock and peripheral registers compare between two cases.