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.

Reply to
elil
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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.

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Rob Gaddi, Highland Technology
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Reply to
Rob Gaddi

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:

Reply to
elil

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

Reply to
John Speth

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

Reply to
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

Reply to
Bruno Richard

Hello,

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

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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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Reply to
gdisirio

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