[Cryptech Tech] arm

[Bernd Paysan]

Am Montag, 12. Januar 2015, 23:22:34 schrieb Jeroen Massar:
> On 2015-01-12 21:00, Rob Austein wrote:
> [..]
> 
> > I halfway seriously proposed RS-232 for (2), but apparently the cool
> > kids won't accept that anymore.
> 
> [..]
> 
> > More serious question, though: what's the least bad hardware interface
> > we can use across the security perimeter?  Eg, would doing our own
> > UDP-like encapsulation over raw ethernet frames be better than USB?
> 
> TLDR:
> #1 serial is simple (great for the small device)
> #2 USB with a USB<->serial dongle
> #3 Ethernet, but then only do Ethernet, not IP
> - need power for the device (usb-power or external brick or PSU?)

If you take the relatively inexpensive Stellaris Launchpads, you have

#1 a UART with an USB<->serial chip
#2 Ethernet
#3 USB-OTG (so you can implement USB client directly)
#4 SPI
#5 I²C
#6 bit-banging stuff, e.g. LEDcomm (using two red LEDs to communicate without 
electric contact).

The LEDcomm stuff might be interesting if you have a tamper-boundary in a 
sealed pressure chamber, and you want power e.g. through Qi (receiver module 
inside the chamber, charger outside), to avoid drilling holes into the 
pressure chamber.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/
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