Make sure you compile with debug info enabled and no optimization. Then, since
you mentioned you have a Segger J-Link JTAG probe, I highly recommend you use
Segger’s debugger Ozone (free J-Link probes) — you’ll be able to easily
single-step and determine what’s going wrong…
If you have a J-Link then you are in business and it shouldn't be
difficult to find the problem. You can use the J-Link like this:
* Start U-Boot and break out to the prompt. This will initialize the
SDRAM.
* Then load NuttX in SDRAM and debug it.
The first think I would want to know is does the code get to nsh_main().
* gdb> file nuttx
* gdb > b nsh_main
* gdb> mon reset
* gdb> c
If you get there, then all of the initialization went OK. Then put a
breakpoint on fputs(). You should hit it via
nsh_session.c: fputs(g_nshgreeting, pstate->cn_outstream);
If you get there then it is at least trying to get something on the
serial console, but is failing for some reason: maybe wrong UART or
wrong pin configuration.
