[Cryptech Tech] Alpha board main CPU change

[Fredrik Thulin]

Hi all

We've just finished two days of core team face to face meetings in Stockholm. 
During these days, we unanimously decided to change the design for the 
upcoming Alpha from using an ARM A9 to an ARM M4.

The reasoning is that we want to reduce complexity of the Alpha board for both 
economical and technical reasons. Yes, we know a number of people on this list 
suggested going with an M4 instead of an A9 months ago =).

The technical reasons I would summarize as we have now gained confidence that 
an A9 would be overkill, we wouldn't really save that much by copying the A9 
design from the Novena, and shaving off unnecessary complexity will speed up 
design, assembly and perhaps most important of all for our project - allow for 
more review.

So... those interested might want to download the latest and greatest file 
from https://wiki.cryptech.is/browser/doc/design/Alpha_board_drawing.pdf

(briefly, the plan is to use an STM32F4429 ARM Cortex M4 CPU running at 180 
MHz. 128 MB of SDRAM, using the FMC interface to connect to the FPGA instead 
of the Freescale EIM interface. As I understand it, the FMC interface will be 
at least as fast as we were going to push the EIM).

/Fredrik