[Cryptech Tech] dev-bridge board

[Fredrik Thulin]

On Wednesday, December 09, 2015 03:15:10 PM Paul Selkirk wrote:
...
> 2) Can we use a portion of the ARM internal flash memory for data
> storage? If so, what address range?

The device has 2 mbyte of flash, that can be used for both code and data. The 
device maps the address range 0x00000000-0x001fffff to wherever it's running 
from (in our case: flash).

> 3) How do we access the Master Key Memory? I see that it's a 23K640-I/SN
> 64K SPI Bus Low-Power Serial SRAM. Is there code to talk to it?
> HAL_SPI_MODULE_ENABLED is not defined in the default HAL configuration.

On the alpha, the MKM is connected to the FPGA and AVR. Since there were no 
more pins available on the Novena FPGA connector, I connected it to the ARM 
and AVR on the dev-bridge board - mostly to be able to verify the schematics.

It is connected to SPI1 on the ARM, and you would need to define 
HAL_SPI_MODULE_ENABLED as you identified - or maybe target the AVR instead.

Testing the MKM as well as the RTC is on my list of things to do before we 
make any alpha boards. If you want to give it a go just let me know so we 
don't work on the same thing.

> 4) Looking further down the road, is there code or documentation for the
> AVR tamper detect MCU?

I can push the led-test program for the AVR if Rob could please refresh my GPG 
key again.

> I can't help noticing that there are 8 exposed
> GPIO headers for the AVR. Will those be used for an external tamper
> circuit, or is this the back door to the MKM?

If you remember some people wanted to start experimenting with tamper sensors, 
but the only one we could get consensus on putting on the alpha board was the 
panic button =). Therefor, we added 8 GPIOs.

> 5) What are all these extra power headers? Are they for the alpha board,
> against the day when it's no longer tethered to the Novena?

They are handy when one for example develops a small tamper sensor and want to 
connect it to the AVR GPIOs, to power the sensor. Also they serve as test 
points for power - which is what one would start by looking at if a board 
doesn't work.

/Fredrik