Anelok: design evolution overview

Werner Almesberger werner at almesberger.net
Wed Apr 23 06:04:31 EDT 2014


I made a little doogle about the some of the design aspects of Anelok,
things discarded, things being evaluated, and also some idea for a
possible future:

http://downloads.qi-hardware.com/people/werner/anelok/tmp/evol-hw.pdf

Most of it should be self-explaining. The little "post-it" boxes list
characteristics and benefits in black, disadvantages or issues in red.

There's one new item in that diagram: the Nordic nRF51822 BTLE chip.
Openly available documentation: [1]. What Google finds: [2, 3]
A quick comparison:

TI CC2543 (this is what's currently in the Y-Box):
  - does not officially support BTLE
  - should be able to do BTLE, with a bit of hacking
  - 8051 core
  - RF-based RNG
  - documentation openly available
  - small (32-QFN), USD 2.52 @ 1000
TI CC2541:
  - officially supports BTLE
  - closed vendor stack uses secret knowledge to enable BTLE features
  - 8051 core
  - RF-based RNG
  - documentation openly available
  - large (48-QFN), USD 2.72 @ 1000
Nordic nRF51822:
  - officially supports BTLE
  - hardware seems to be properly documented
  - ARM Cortex M0
  - thermal RNG
  - technical documentation requires registration
  - large (48-QFN) or (soon) BGA, USD 1.92 @ 1000

The CC2541 would be TI's "official" BTLE chip, but since all its
goodies are closed we may just as well use the CC2543, which is
cheaper and smaller.

The nRF51822 looks pretty sexy but I'm reluctant to make yet another
RF chip change at the moment since this would a) delay the project
further, and b) one would have to go with a fine comb over the
documentation to see whether all that's needed is really there.

And yes, the registration barrier is a bit worrying, too. It's one of
the warning signs that one may encounter more attitude issues further
down the road.

[1] http://www.nordicsemi.com/eng/nordic/download_resource/20351/6/38628533
[2] http://media.digikey.com/pdf/Data%20Sheets/Nordic%20Semiconductor%20PDFs/NRF51822_Spec_v1.2.pdf
[3] http://www.freqchina.com/cn/down.asp?ID=135

- Werner



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