Recommended Development Hardware

NIIBE Yutaka gniibe at
Fri Apr 19 02:26:06 CEST 2019

Charles Surett <surettcharles at> wrote:
> What is the currently recommended development hardware? I want to be
> able to make a Gnuk device and be able to debug it without the need to
> solder.

When I started the development, it was Olimex STM32-H103 + ARM-USB-TINY.
I still use it occasionally.  Good point is the availability over ten

Now, if you have easy access to China, I'd recommend a board with
GD32F103, like:

Well, I don't have experience with this board.  I think it's good to
have a solid connector to a programmer (just like Olimex STM32-H103).
It's good for development.

I think that the good reference for STM32F103 boards is:

Among those, Maple Mini and Blue Pill are supported by Gnuk.  Adding
support for other boards is easy.

Please note that you need a programmer to flash/debug a board.
ST-Link/V2 (and its clone) is popular, but the firmware is proprietary.

While I don't have experience with it, IBDAP-CMSIS-DAP JTAG/SWD debug
adapter is good one which comes with all information (including its
schematics, firmware, etc.):

> I also was wondering if it is possible to port Gnuk to a device like a
> Teensy.

Technically speaking, it's possible.  However, I won't call it "Gnuk",
when it runs on something like Cortex-M4F.  It has so many features
which might kill the purpose of Gnuk to be smaller and less complexity.

Here is some techinical discussion.

For Cortex-M0+, I once tried (for FS-BB48), but I gave up, because it
doesn't have a good multiplier.  If you can wait longer (say, up to 1.2
second for EdDSA signing), it may be useful.

For Cortex-M4F, I am porting Chopstx (the thread library) to STM32L432.
I learned that its USB module is mostly same, and it works now.  I have
a USB driver for Freescale (now NXP) for MKL27Z.  Thus, I think that
porting Chopstx to MK* chip with Cortex-M4F is feasible (I guess, not
that hard).

Then, when you will support random number generation and flash ROM
routines, Gnuk can run on that chip.

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