Concerning an ISP based GDB server - I think there is no one.
First, I searched for something like this, without an result.
Second, I had a closer look at the ISP protocol (see doc.# UM10360)
There are none of the commands one would expect for debugging, such as
setting/removing breakpoint and reading register contents.
Unless NXP did not document it.
But I think the ISP is just an easy and save method for OEM customers to
provide an interface for field SW updates. These are often handled by personnel
with limited tools and knowledge of device internals. With JTAG, one would
eventually have to mess around with code protection issues…
Since Code-Red is also Eclipse based, it comes with separate GDB server, which
is called crt_emu_cm3_nxp. Calling it with ‘-help’ from the command line reveals
that is also usable for standalone flashing of the controller.
I need to check if it works with gdb (thus can be used by any gdb-aware IDE,
such as CodeBlocks), and if the the same flashing/debugging restrictions apply.