Several of the applications that I've worked on require long periods of sleep followed by a wake up and processing, then back to sleep. I've found the processing to take less time than the wake up. In this case stand-by (or shutdown current) and wake-up time dominate the power utilization function.
I find that every manufacturer touts that their processor is the lowest power. I've found the only way to truly decide is on an application by application basis. Because, each processor has it's niche that it exploits. If your application fits that niche then their processor is the lowest power.
Finding some type of objective measure would be useful, but you never know what the final numbers are until the application has been optimized for the selected processor.
Any analysis done on the equivalent controllers from Free scale and others? By the way all the comments added to this discussion generates very useful information for the designers. Thanks for all the thoughts and experience shared!
Hello Jason, Thanks for your answer. I agree with your thought "Try samples and examine results". And, overall, I'me sure that today TI and Microchip as well are making a good work and have interesting devices. On teh other hand,I don't agree with arbitrary misleading, as the one about the code to move data. Try to examine this one for MSP430, supposing two 32-bytes arrays starting at StrtAddr1 (source) and StrtAddr2 (dest):
bis.b #TestBit,TestPort ;pin setted at the end of this
move #16,r4 ;2T; 32 bytes are 16hword
move #StrtAddr1,r5 ;2T
loop: move @r5+,StrtAddr2-StrtAddr1-2(r5) ;5T
dec r4 ;1T
jnz loop ;2T
bic.b #TestBit,TestPort ;4T
Summing all states results in 8*16+8=136T (I apologize for mistakes); at 4MHz it means 32usec and not 80usec, please update your test results.
Surely, "C" against "assembly" is a misleading comparison, I can't make the same error I find in someone's reasonement; But (I used PIC in early age, about in 1992, I dont' remember its assembly) try to write "16-byte-move" routine in assembly and compare results. That is, when between a uP task and uP code there is a Compiler, its behaviour can change things at all.
In every case -and I conclude- I show I'm not blind: code compactness in MSP430 isn't good (eg: "byte" instruction are exactly long as "word" one; e.g: Hitachi H8s is better), and I remember PIC (I used old 16C71) was very very compact.On the other hand,Pic hasn't powerful instruction as "mov @r5+,OFFSET(r5) that atomically read WORD, write WORD and update pointer. Core comparison is often difficult, but You can't exaust this thema saying "PIC instruction are 1-cycle, TI are 1..6cycles, so we are SURELY better", without considering in detail the differences between the actions of one and other instruction.
Have a good day
KaiserSoze and xorbit,
Microchip submitted the above table to EE Times, to provide their readers with an at-a-glance comparison of published data. I agree with xorbit—don’t take either company’s word for it; investigate the source documents and decide for yourself which MCU will best meet your needs. Better yet, obtain samples and do your own comparison.
-Jason Tollefson, 16-bit Microcontroller Senior Product Marketing Manager, Microchip Technology Inc.
Indeed, as KaiserSoze brings out, it looks as if you're deliberately trying to mislead when you mix the best of each of your architectures as if there were one part that does it all, which isn't true. Unfortunately, I have gotten this feeling pretty much every time I have investigated Microchip parts when some impressive marketing claim had drawn my attention. Upon further investigation, there usually was some gotcha or clever specmanship involved, which has made me wary of any Microchip marketing claims.
I couldn't find full specs on the MSP430 Wolverine parts, but just taking a quick look at your datasheet for the PIC24FJ128GA310 and the datasheet for the MSP430FR5720, I couldn't help but notice that Microchip's typical power consumption column on page 361 has a note saying "Data in the Typical column is at 3.3V, 25°C unless otherwise stated". But each row states -40°C to +85°C. Which is it? The MSP430 power specs seem to cover -40°C to +85°C.
I'm not saying your claims are untrue, but previous experience has taught me to be very cautious of "the Microchip spin". I have also not evaluated the performance of the PIC24 series, I have previously compared the MSP430 to the PIC16 series, based on similar cost, and there was no contest there.
I would suggest to anyone doing this evaluation to look carefully beyond the marketing and into the technical details. Also, there are other low power contenders around, the Renesas RL78 comes to mind (66uA/MHz).
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