STM8L151 vs MSP430 performance benchmark

Dear Sirs,

Me and my colleagues are involved now with selection of new MCUs for
our new projects for the following 2 years.The desired MCUs should
have very low power consumption and some of them should have very low
price.I looked at all existing in the market MCUs and finally reduced
the selection to 2: either STM8L series or MSP4305xx. I haven't too
much time to continue the serious investigation and therefore I'd like
to get a recommendation from you. I need to estimate which of those
MCU's will give me the lower current consumption in the active mode.
All the manufacturers provide the current consumption in uA/1 Mhz, so
supposedly I can compare between them, BUT if MSP430 and STM8L have
different cores with different instruction sets, this uA/1 MHz
parameter is not correct. Recently I've seen some presentations where
I've encountered current consumption in uA/DMIPS, which is more
correct, but I don't know whether I can trust to these numbers or not,
since I don't know how did they get it. MSP430 is 16-bit and STM8l is
8-bit core. Does it mean that TI have better performance ? I think it
don't, since if I write code that is intended for 8-bit CPU it will be
faster on STM8L but if I write code that is intended for 16-bit CPU,
it will be faster on MSP430. My question is to those, who have been
facing the same dilemma. What did you finally choose ? Did anyone here
test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?

Thank you in advance,
E.L.

On 11/10/2010 9:40 AM, elil wrote:
> Dear Sirs,
>
> Me and my colleagues are involved now with selection of new MCUs for
> our new projects for the following 2 years.The desired MCUs should
> have very low power consumption and some of them should have very low
> price.I looked at all existing in the market MCUs and finally reduced
> the selection to 2: either STM8L series or MSP4305xx. I haven't too
> much time to continue the serious investigation and therefore I'd like
> to get a recommendation from you. I need to estimate which of those
> MCU's will give me the lower current consumption in the active mode.
> All the manufacturers provide the current consumption in uA/1 Mhz, so
> supposedly I can compare between them, BUT if MSP430 and STM8L have
> different cores with different instruction sets, this uA/1 MHz
> parameter is not correct. Recently I've seen some presentations where
> I've encountered current consumption in uA/DMIPS, which is more
> correct, but I don't know whether I can trust to these numbers or not,
> since I don't know how did they get it. MSP430 is 16-bit and STM8l is
> 8-bit core. Does it mean that TI have better performance ? I think it
> don't, since if I write code that is intended for 8-bit CPU it will be
> faster on STM8L but if I write code that is intended for 16-bit CPU,
> it will be faster on MSP430. My question is to those, who have been
> facing the same dilemma. What did you finally choose ? Did anyone here
> test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?
>
> Thank you in advance,
> E.L.

I've done some work with the MSP430 in the past and found it to be a 
nice little architecture.  Haven't used the STM8L, but I just went to 
give a quick look and ST's new webpage makes me want to claw my eyes out.

-- 
Rob Gaddi, Highland Technology
Email address is currently out of order

Thanks Rob,

I have to mention that I haven't understood what "to claw my eyes out"
expression means. My dictionary has the same difficulcy (-:. Indeed ST
have changed their web-site and it takes time to to become accustomed
to it.



Rob Gaddi =D7=9B=D7=AA=D7=91:
> On 11/10/2010 9:40 AM, elil wrote:
> > Dear Sirs,
> >
> > Me and my colleagues are involved now with selection of new MCUs for
> > our new projects for the following 2 years.The desired MCUs should
> > have very low power consumption and some of them should have very low
> > price.I looked at all existing in the market MCUs and finally reduced
> > the selection to 2: either STM8L series or MSP4305xx. I haven't too
> > much time to continue the serious investigation and therefore I'd like
> > to get a recommendation from you. I need to estimate which of those
> > MCU's will give me the lower current consumption in the active mode.
> > All the manufacturers provide the current consumption in uA/1 Mhz, so
> > supposedly I can compare between them, BUT if MSP430 and STM8L have
> > different cores with different instruction sets, this uA/1 MHz
> > parameter is not correct. Recently I've seen some presentations where
> > I've encountered current consumption in uA/DMIPS, which is more
> > correct, but I don't know whether I can trust to these numbers or not,
> > since I don't know how did they get it. MSP430 is 16-bit and STM8l is
> > 8-bit core. Does it mean that TI have better performance ? I think it
> > don't, since if I write code that is intended for 8-bit CPU it will be
> > faster on STM8L but if I write code that is intended for 16-bit CPU,
> > it will be faster on MSP430. My question is to those, who have been
> > facing the same dilemma. What did you finally choose ? Did anyone here
> > test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?
> >
> > Thank you in advance,
> > E.L.
>
> I've done some work with the MSP430 in the past and found it to be a
> nice little architecture.  Haven't used the STM8L, but I just went to
> give a quick look and ST's new webpage makes me want to claw my eyes out.
>
> --
> Rob Gaddi, Highland Technology
> Email address is currently out of order

> Me and my colleagues are involved now with selection of new MCUs for
> our new projects for the following 2 years.The desired MCUs should
> have very low power consumption and some of them should have very low
> price.I looked at all existing in the market MCUs and finally reduced
> the selection to 2: either STM8L series or MSP4305xx. I haven't too
> much time to continue the serious investigation and therefore I'd like
> to get a recommendation from you. I need to estimate which of those
> MCU's will give me the lower current consumption in the active mode.
> All the manufacturers provide the current consumption in uA/1 Mhz, so
> supposedly I can compare between them, BUT if MSP430 and STM8L have
> different cores with different instruction sets, this uA/1 MHz
> parameter is not correct. Recently I've seen some presentations where
> I've encountered current consumption in uA/DMIPS, which is more
> correct, but I don't know whether I can trust to these numbers or not,
> since I don't know how did they get it. MSP430 is 16-bit and STM8l is
> 8-bit core. Does it mean that TI have better performance ? I think it
> don't, since if I write code that is intended for 8-bit CPU it will be
> faster on STM8L but if I write code that is intended for 16-bit CPU,
> it will be faster on MSP430. My question is to those, who have been
> facing the same dilemma. What did you finally choose ? Did anyone here
> test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?

I've used the MSP430 in an application that the circuits off mode current 
draw needed to be as small as possible.  That exercise was an eye opener for 
me.  I found that no matter how low I got the MSP430 current draw, the 
circuit around it was always drawing the most of the current in the circuit. 
Some of my pins were connected to external devices that sucked or sunk 
current much higher than what the MSP430 was consuming internally.  I admit 
that a better overall circuit design could have helped and that no two 
applications are the same.  But the lesson I learned is these tiny current 
MCUs are nearly equivalent in practice.  As always, YMMV.

JJS

In article <ibeod0$9o6$1@speranza.aioe.org>, johnspeth@yahoo.com says...
> > Me and my colleagues are involved now with selection of new MCUs for
> > our new projects for the following 2 years.The desired MCUs should
> > have very low power consumption and some of them should have very low
> > price.I looked at all existing in the market MCUs and finally reduced
> > the selection to 2: either STM8L series or MSP4305xx. I haven't too
> > much time to continue the serious investigation and therefore I'd like
> > to get a recommendation from you. I need to estimate which of those
> > MCU's will give me the lower current consumption in the active mode.
> > All the manufacturers provide the current consumption in uA/1 Mhz, so
> > supposedly I can compare between them, BUT if MSP430 and STM8L have
> > different cores with different instruction sets, this uA/1 MHz
> > parameter is not correct. Recently I've seen some presentations where
> > I've encountered current consumption in uA/DMIPS, which is more
> > correct, but I don't know whether I can trust to these numbers or not,
> > since I don't know how did they get it. MSP430 is 16-bit and STM8l is
> > 8-bit core. Does it mean that TI have better performance ? I think it
> > don't, since if I write code that is intended for 8-bit CPU it will be
> > faster on STM8L but if I write code that is intended for 16-bit CPU,
> > it will be faster on MSP430. My question is to those, who have been
> > facing the same dilemma. What did you finally choose ? Did anyone here
> > test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?
> 
> I've used the MSP430 in an application that the circuits off mode current 
> draw needed to be as small as possible.  That exercise was an eye opener for 
> me.  I found that no matter how low I got the MSP430 current draw, the 
> circuit around it was always drawing the most of the current in the circuit. 
> Some of my pins were connected to external devices that sucked or sunk 
> current much higher than what the MSP430 was consuming internally.  I admit 
> that a better overall circuit design could have helped and that no two 
> applications are the same.  But the lesson I learned is these tiny current 
> MCUs are nearly equivalent in practice.  As always, YMMV.
> 
That's a really good point.   I've done a lot of low-power MSP430 
designs.   Getting to the lowest power always requires careful
consideration of the circuitry connected to the MPU.  Sometimes
you have to set MPU pins to high-impedance inputs to avoid
source or sink currents.  Other times, doing so will put connected
external CMOS inputs into the mid-level voltages where they 
cause the device to start sinking more current than it should.

Getting any system to minimum power in a sleep mode  is a tough
job for even experienced designers.  The results depend a lot
on both the MPU and the external circuitry.


Mark Borgerson

Hi all,

I have been working on STM8L devices with much happiness: The tools
are of good quality, and the devices themselves are well thought.
It looks to me that the STM8 family is targeted towards high-volume
applications, although the MSP430 is more for hobbyists.

One interesting note: Although STM8 is marketed as an 8-bit device
(understand "cheap"), all the arithmetic is performed in 16-bit, so
the device has much better MIPS performance then "real" 8-bitters such
as 8051 and the like.

My $.02,
Bruno

>Dear Sirs,
>
>Me and my colleagues are involved now with selection of new MCUs for
>our new projects for the following 2 years.The desired MCUs should
>have very low power consumption and some of them should have very low
>price.I looked at all existing in the market MCUs and finally reduced
>the selection to 2: either STM8L series or MSP4305xx. I haven't too
>much time to continue the serious investigation and therefore I'd like
>to get a recommendation from you. I need to estimate which of those
>MCU's will give me the lower current consumption in the active mode.
>All the manufacturers provide the current consumption in uA/1 Mhz, so
>supposedly I can compare between them, BUT if MSP430 and STM8L have
>different cores with different instruction sets, this uA/1 MHz
>parameter is not correct. Recently I've seen some presentations where
>I've encountered current consumption in uA/DMIPS, which is more
>correct, but I don't know whether I can trust to these numbers or not,
>since I don't know how did they get it. MSP430 is 16-bit and STM8l is
>8-bit core. Does it mean that TI have better performance ? I think it
>don't, since if I write code that is intended for 8-bit CPU it will be
>faster on STM8L but if I write code that is intended for 16-bit CPU,
>it will be faster on MSP430. My question is to those, who have been
>facing the same dilemma. What did you finally choose ? Did anyone here
>test the performance of STM8L vs MSP430 or vs PIC18 or PIC16 ?
>
>Thank you in advance,
>E.L.
>

Hello,

I am maintaining a page with benchmarks for various architectures
including STM8, MSP430 and many others:

http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:metrics

Detailed benchmarks are into the test reports, the code is available
too. The STM8 performs really well for a 8bit, it is particularly
efficient at context switching, probably because its few internal
registers.
The STM8L is characterized by its DMA channels and peripherals
commonality with the STM32, it looks like a mini-STM32 with an
8bit core, interesting feature if you need a growth path.

I hope this can help.

regards,
Giovanni
	   
					
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