A while ago I discussed the Anelok design with Bluetooth hacker Mike Ryan, and he strongly recommended using the Nordic nRF51822 instead of the the TI CC2543.
The idea for the TI CC2543 is to write the lower layers of an open BTLE stack from scratch, and at some point mix this with the upper layers from BlueZ. The main benefit of this approach is that it's 100% open. The main drawback is that it's a lot of work, especially given that the hardware doesn't quite support the BTLE frame format, and thus would require some creative software tweaks. After looking (again [1]) at the nRF51822 documentation, I'm now reasonably confident that one could write an all-Free stack also for this chip. But it has the added benefit that Nordic provide a (closed) stack as well, which should help to keep the development time for a first working prototype down. Another feature that may become important given recent regulatory trends is that the nRF51822 (like the Kinetis MCUs) can be protected against unauthorized Flash modification. I.e., one could write a boot loader that only accepts signed binaries. The CC2543, on the other hand, can always be fully erased and then accepts any new firmware. Further advantages of the nRF51822 include that it's a Cortex M0 (so we don't need SDCC for the ancient 8051 core of the CC2543) and that it has enough Flash and RAM for the entire BTLE stack. That may end up weakening the role of the cMCU, but I think any possible optimizations there can wait until later. I haven't put too much work into the CC2543 so far, so the time lost by switching RF chips again wouldn't be excessive. Of course, such a change will still obsolete all the RF sections of the 2014/Mk2/CR2032 boards made so far. [1] http://lists.en.qi-hardware.com/pipermail/discussion/2014-April/010574.html Opinions ? - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
