nRF51822 as co-processor for Microbit

RE: nRF51822 as co-processor for Microbit

JohnBrown — Thu, 27 Aug 2015 18:45:33 GMT

Depends which version of the nRF51822 is used on the Microbit. The later versions have 256K Flash and 32K RAM, as far as I know, and even the Rev 2 has 256K Flash, but only 16K RAM. Maybe someone from Nordic could say exactly which chip is used?

RE: nRF51822 as co-processor for Microbit

Sean — Thu, 27 Aug 2015 14:49:53 GMT

I am - I was pointed to the page and read from the top (duh). So, I have 16K of RAM & 128K of Program ROM (well, flash-RAM, but you know what I mean).

Has there ever been an asynchronous compression scheme in which the encode doesn't have to be real time. LD-CELP (16Kb/s) gives reasonable quality and because the frames are so short, going between voiced & unvoiced will be less jarring.

Frankly, without a proper spec on how the Bluetooth & main CPU link up (among other things), I don't plan to write a custom speech codec.

Oh - I see that Nordic themselves favour ADPCM. Very low complexity BUT can be improved. Note that there is an unused code (0 & -0 are the same, as a multiplier).

Appreciate the time, friends.

RE: nRF51822 as co-processor for Microbit

RK — Wed, 26 Aug 2015 00:31:04 GMT

There's some confusion here - the Microbit has just the nrf51822 on it with the one Cortex M0 processor.

RE: nRF51822 as co-processor for Microbit

follower — Tue, 25 Aug 2015 20:36:58 GMT

Are you confusing the nRF51 specification with the nRF52 specification?

My understanding is that the only CPU on the Microbit is that contained in the nRF51 onboard (see en.wikipedia.org/.../Micro_Bit which has the "ARM® Cortex™ M0 CPU" specification (www.nordicsemi.com/.../nRF51822).

The "ARM® Cortex™-M4F CPU" specification is for the recently announced nRF52 series (www.nordicsemi.com/.../nRF52832) which is not onboard the Microbit.

I look forward to seeing the impact of the Microbit as my life and career were significantly impacted by my experience with the original BBC Micro. :)