32Bit Moteino

[jra]

If you were to look at  supporting the MSP430 I would also take a serious look at the MSP432 for all of the reasons outlined in http://e2e.ti.com/support/microcontrollers/msp430/f/166/t/411030.  The biggest downside is the relative newness of the MSP432 family, less than a year since it was announced.

[joelucid]

Given how some of us love their RTC here's Ambiq's ARM mcu: http://ambiqmicro.com/system/files/Apollo_MCU_Data_SheetDS0010V0p45.pdf. 196nA sleep with RTC and ram retention and 34uA per MHz, cortex m4f. I don't think there's anything lower power available.

Really cool mcu but tough package options.

[WhiteHare]

Given how some of us love their RTC here's Ambiq's ARM mcu: http://ambiqmicro.com/system/files/Apollo_MCU_Data_SheetDS0010V0p45.pdf. 196nA sleep with RTC and ram retention and 34uA per MHz, cortex m4f. I don't think there's anything lower power available.

Really cool mcu but tough package options.

Nice find!  According to the benchmark results, it tests out as significantly better than all the others:  http://www.eembc.org/ulpbench/
and twice as good as the Atmel one that I had referenced above.

[bborncr]

Some of my applications do need some more ram and a processor with more interrupts and other goodies such as an RTC. As a test we took an Adafruit M0 Feather and connected it to an RFM69:

RFM69  --->   Feather M0
MISO             MOSI
MOSI             MISO
SCK               SCK
NSS               A2
DIO0 (INT)     10

The only changes on the RFM69 library are in RFM69.h on lines 49 and 50:

Code Select Expand

#define RF69_IRQ_PIN     10
#define RF69_IRQ_NUM     10

This should work with any SAMD21 arduino such as the Sparkfun SAMD21 breakouts, all the Adafruit M0 Feathers and the Arduino M0s. So far it seems to be working just fine. Props to @wifixcort who figured this out.
If we are missing something please let us know!

[WhiteHare]

@bborncr Thanks for your post.  For 32 bit, you might also be interested in some of the new "ultra low power" STM32 eval boards, which are $10.99 on Digikey and $10.33 on Mouser:  http://www.digikey.com/product-search/en/programmers-development-systems/evaluation-boards-embedded-mcu-dsp/2621773?k=stm32l0&pv47=27856&pv47=27857&FV=fff40028&mnonly=0&newproducts=1&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=500

[Felix]

Never to say never, but at this point I doubt there will be an ARM based Moteino.

Steve Chamberlin from Big Mess'o'Wires wrote an excellent summary of why ARM is hard to get started with, and his points are exactly why I did not mess around with ARM so far, so if you want my standpoint read his article, he is spot on on everything. In addition - a main personal reason (and I believe of most Moteino users) is that for the stuff I do I don't need ARM - 8 bit AVR is easy, people get it (well in general), it's super widely known and supported and documented, it does just fine and is low power enough as proven in many excellent research topics in this forum. If you need DSP use an ARM or FPGA.

[WhiteHare]

Yup, I agree with you.  Nonetheless, I was over at Mouser earlier today shopping for a few odds and ends when I unexpectedly stumbled across a new component that's was foreshadowed by the discussion earlier earlier in this thread: it's a fairly small package (just 14x14mm in size) that contains both an 915Mhz FSK radio (with bitrates up to 500kbps) and one of the recently discussed "ultra low power" 32Mhz ARM processors that sports 16KB RAM and 128KB Flash:   http://www.mouser.com/pdfdocs/DM00133214-2.pdf 

[joelucid]

it's a fairly small package (just 14x14mm in size)

That's 14x14mm including the chip antenna! Wow.

[SadE54]

it's a fairly small package (just 14x14mm in size)

That's 14x14mm including the chip antenna! Wow.

Is the ARM Cortex programmable ? It's seems it's only the core of the module that need to communicate with another host cpu no ?