[Cryptech Tech] Lattice boards for developing a custom master key memory

[Peter Stuge]

I like this idea, but I would definitely stick with a synchronous bus
such as SPI.


Joachim Strömbergson wrote:
> We are currently considering using the Lattice ICE devices. One of the
> chief reasons is the project IceStorm

I am a fan of Yosys and the iCE40 devices, and also made a board with
the hand-solderable VQ100 HX1K.


I would recommend buying either the Olimex iCE40HX1K-EVB:
https://www.olimex.com/Products/FPGA/iCE40/iCE40HX1K-EVB/open-source-hardware

..or maybe maybe the iCEstick.

The Olimex iCE40HX1K-EVB has 28 IOs and a 100 MHz oscillator which is
available externally, but no USB interface, so flashing a bitstream
requires another device (similar to flashing the Alpha STM32) - but OTOH
flashing only needs to be done once.

The iCEstick includes an FTDI USB chip for easy flashing, but only
has 24 IOs spread over three connectors, only has a 12 MHz oscillator
and is designed to only be powered via USB.

Note that HX1K has no PLL in the VQ100 package used on both these
boards, so no clock can run faster than the oscillator. But a good design
should not rely on a clock for tamper detect anyway, I think that should
be asynchronous.


A more powerful option would be the Olimex iCE40HX8K-EVB:
https://www.olimex.com/Products/FPGA/iCE40/iCE40HX8K-EVB/open-source-hardware

This is similar to the iCE40HX1K-EVB but has about 6x logic capacity,
2 PLLs and another 132 IOs.


Pro iCEstick: USB interface
Con: Made by Lattice

I like to support Olimex when possible, since they are very strong if
not leading when it comes to open hardware. They use only open source
design software and have always been very good at publishing designs
as open hardware. They ship from EU stock immediately using pretty
much any courier.


//Peter