Development Environment
=======================


Hardware
--------

For development, it is highly recommended to have JTAG debugger or SWD
debugger.

For boards with DFU (Device Firmware Upgrade) feature, such as DfuSe,
it is possible to develop with that.  But it should be considered
*experimental* environment, and it should not be used for usual
purpose.  That's because it is basically impossible for DfuSe
implementations to disable reading-out from flash ROM.  It means
that your secret will be readily extracted by DfuSe.

For JTAG debugger, Olimex JTAG-Tiny is good and supported well.  For
SWD debugger, ST-Link/V2 would be good, and it is supported by
the tool of tool/stlinkv2.py.


OpenOCD
-------

For JTAG debugger or SWD debugger, we can use OpenOCD.

Note that ST-Link/V2 is *not* supported by OpenOCD 0.5.0.  It will be
supported by version 0.6 or later, as current development version
supports it.


GNU Toolchain
-------------

You need GNU toolchain and newlib for 'arm-none-eabi' target.

See http://github.com/esden/summon-arm-toolchain/ (which includes fix
of binutils-2.21.1) for preparation of GNU Toolchain for
'arm-none-eabi' target.  This is for GCC 4.5.

Note that we need to link correct C library (for string functions).
For this purpose, our src/Makefile.in contains following line:

	MCFLAGS= -mcpu=$(MCU) -mfix-cortex-m3-ldrd

This should not be needed (as -mcpu=cortex-m3 means
-mfix-cortex-m3-ldrd), but it is needed for the configuration of
patch-gcc-config-arm-t-arm-elf.diff in summon-arm-toolchain in practice.

In ChibiOS_2.0.8/os/ports/GCC/ARM/rules.mk, it specifies
-mno-thumb-interwork option.  This means that you should not link C
library which contains ARM (not Thumb) code.

Recently, there is "gcc-arm-embedded" project.  See:
https://launchpad.net/gcc-arm-embedded/

It is based on GCC 4.6.   For version 4.6-2012-q2-update, you'd
need "-O3 -s" instead of "-O2" and it will be slightly better.



Building Gnuk
-------------

Change directory to ``src``:

  $ cd gnuk-VERSION/src

Then, run ``configure``:

  $ ./configure --vidpid=<VID:PID>

Here, you need to specify USB vendor ID and product ID.  For FSIJ's,
it's: --vidpid=234b:0000 .  Please read section 'USB vendor ID and
product ID' above.

Type:

  $ make

Then, we will have "gnuk.elf".