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Re: STM32!

Posted: Mon Oct 28, 2019 4:44 pm
by QMESAR
If you want to compare performance you should at least run the PIC32 and the STM at the same clock speeds
are you running the STM also at 40MHZ?

What I normally do is I make a while 1 loop which set the pin High then 2 NOP cycles the set the Pin low and again 2 NOP cycles
only this and you can more or less see the what actually is going on ,for the exact performance you can not actually measure this way as the NOP plus the code to toggle the pins does use time
Use plain C not Flowcode components or even assembler if you want to compare performance ,search the MCP forum on this topic you will get some good info .
I am quite sure at the same clock speeds the STM will not out power the MIPS core :D the best to compare chips is to look at the tested Dmips value for the core these values are derived from independent testing in many scenarios and code which reflects the power of the core what you are doing is in no way a way to decide if the STM is better than the PIC search for the DMIPS value you will find it

Re: STM32!

Posted: Mon Oct 28, 2019 6:01 pm
by Alkaline
You are definitely right.

My way of doing the test is hasty and obviously not true.

The problem that our core business is not writing code for the MCU but for other devices like external dsp ect. The use of the Flowcode is allowed to accelerate the development of projects enormously, allowing us to focus on where we put our knowledge.

The interest in the stm32 family has matured beyond an economic factor also because they allow operating at 1.8v or 3.3v.

This thing becomes fundamental when to integrate MCU with other devices without having to use the level shifter that take up space and make the costs rise!
Obviously I would like to exploit the microcontroller correctly, but I always have to keep in mind the time and goals set!

Re: STM32!

Posted: Mon Oct 28, 2019 6:17 pm
by QMESAR
Hi

I understand all of this worked many years in automotive R&D :D

If you look at the PIC32 datasheet you will notice that you can run from 1.75V (this is the voltage where you start to loose RAM) thus just as in the case of STM you can run voltage levels from 1.8-3,3 or 3,6V.(I see no difference here between PIC32 and STM )

I am sure you are aware that the performance of any micro controller(operating MIPS/Frequency) reduce as the voltage is reduced this is shown on page 280 of the PIC32MX470 datasheet and I am quite sure this is the case with the STM too

any case I am not a salesman you use what is best for you :D There is a big miss assumption in the world that ARM 32 bit cores are the alpha and omega which is not the case PIC32 is a great controller with the best performance per MHZ

Re: STM32!

Posted: Mon Oct 28, 2019 7:02 pm
by Alkaline
Thanks for the advices.

I'll try stability in the lab by bringing the chip to 1.8 volts. The chip requires a minimum voltage of 2.3 due to internal ldo.

Theoretically with a lower voltage ldo should be bypassed. (it's not really so, but it's not the right thread to talk about pic)

Absolutely agree about arm. Arm tecnology do not represent the cure for all problems! It is true that working on the same type of CORE allows you to change mcu producer almost instantly but in reality it is not always so.

Re: STM32!

Posted: Mon Oct 28, 2019 7:25 pm
by QMESAR
Hi.

Yes you right this is not the topic to discuss a PIC :D
I just wanted to point out that the test are may be a bit miss leading as your initial post show some bad results from the PIC :D :D
good luck if you need help to toggle the pin with C code let me know I can do something for you
t is true that working on the same type of CORE allows you to change mcu producer almost instantly but in reality it is not always so
this does not really work like this in reality as each vendor add its own peripherals to the core and there are limits /issues etc to get to work with the new vendor, I know this my OEM learned this in a hard way by recalling a huge amount of vehicles few years ago :D

Re: STM32!

Posted: Mon Oct 28, 2019 7:33 pm
by QMESAR
Jurgen
Sorry for high jacking your post :D

Re: STM32!

Posted: Tue Oct 29, 2019 6:35 am
by jgu1
Hi Qmesar!

No problem, at all. I follow your post, interesting, so continue, please :wink:

Br Jorgen

Re: STM32!

Posted: Mon Nov 04, 2019 9:42 pm
by jgu1
Hi Leigh!

I have played with the Nuclea a bit. It seemed to be a very fast and powerfull device. full speed on Ili9341 :D . In Interrupt timer 5 or other, the maxspeed is 122.070Hz
I see the dropdown meny for roll over, but it is not possible to change this. How do I change the speed, please?

Br Jorgen

Re: STM32!

Posted: Tue Nov 05, 2019 8:44 am
by LeighM
Hi Jorgen,
Sorry, looks like that drop box icon is causing confusion.
There is no list for this parameter.
You can just type in a new value instead of the default 65536
Leigh

Note: The calculated frequency is not correct, please ignore it and calculate manually, or use CubeMX. We have not yet found a way to get Flowcode to be able to calculate this for ST ARM devices, due to the complex clock settings.

Re: STM32!

Posted: Tue Nov 05, 2019 9:36 pm
by jgu1
Hi Leigh!

Yes,it work. In my first attemp, It look like it not possible to do something. But I see it is possible to write in the dropdown.

ThankĀ“s.

Br Jorgen