Welcome & 2 questions

sp9mrn
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Joined: Fri Jul 07, 2017 9:23 pm

Welcome & 2 questions

Post by sp9mrn » Fri Jul 07, 2017 9:36 pm

Hi from Poland.
My name is Maciek (Mac) and I generally use arduino, but STM32 look promising.
Simple question for 7 june 2017 - which board is best this moment? (I mean cheap boards). Which should I avoid?
and the second one - can I compare speed of STM32 board with teensy?

Best for all
MAc

ChrisMicro
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Location: Germany

Re: Welcome & 2 questions

Post by ChrisMicro » Sat Jul 08, 2017 8:15 am

The cheapest is the BluePill with an STM32F103.
The best is the STM32F746 Discovery.

Ollie
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Re: Welcome & 2 questions

Post by Ollie » Sat Jul 08, 2017 5:49 pm

The word "best" alone is very subjective. If you can describe your application or problem, then you would get more relevant recommendations for those use cases. For example, I am mainly involved in robotics and copters. I have been very pleased for the blue pill and F103 in general. In that frontier, I am shifting to F407. For compact size and high-quality library, I have been pleased to Teensy 3.2/3.5/3.6. For cases where wireless communication is essential, I have been using ESP8266/32 and RPi 3. For high-speed robotics, I am evaluating the F745. It is little pricey, but wow - it is fast.

In some public projects, I have been using Arduino Mega (6 wheel rover) and Arduino Leonardo (sumo robot), but my guess is that you are not interested in those.

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Pito
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Re: Welcome & 2 questions

Post by Pito » Sun Jul 09, 2017 9:33 am

can I compare speed of STM32 board with teensy?
There are several models of the 32bits Teensies..
T LC - slower than BluePill/MapleMini (and other F103 based boards..)
T 3.2 - faster than BP/MM, slower than Black F407 and above
T 3.5 - slower than Black F407 and above
T 3.6 - faster than Black F407, when both overclocked to 240MHz then the speed is the same :)
Last edited by Pito on Sun Jul 09, 2017 9:42 am, edited 2 times in total.
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ChrisMicro
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Re: Welcome & 2 questions

Post by ChrisMicro » Sun Jul 09, 2017 9:37 am

And whats about the speed of the F746?

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Pito
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Re: Welcome & 2 questions

Post by Pito » Sun Jul 09, 2017 9:38 am

He is looking for cheaper boards, btw..
BP/MM - $3-$4
Blue F103 - $8-$10
Black F407 - $10-$15
Last edited by Pito on Sun Jul 09, 2017 5:42 pm, edited 1 time in total.
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sp9mrn
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Re: Welcome & 2 questions

Post by sp9mrn » Sun Jul 09, 2017 12:58 pm

Thank You. I was not precise when I was asking, sorry.
There are several kinds of f103 boards - blue with yellow jumpers, blue with two buttons, red, black. Which of them is less problematic?
I do not have a specific projest to do (yet) - just want to go from arduino to higher level.
I think in future to use f103 board as a replacement of tennsy in 2 projects -
1. https://sites.google.com/site/lofturj/p ... eter---rev
2. https://sites.google.com/site/lofturj/c ... r-Graphics

I dont know if it has enough speed and math power ;-) but I hope I will test it

Thanks
Mac

dannyf
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Re: Welcome & 2 questions

Post by dannyf » Sun Jul 09, 2017 1:18 pm

which board is best this moment? (I mean cheap boards).
they typically go a few dollars - mine were like $2 shipped. you can get it done cheaper if you buy raw chips and do the fabrication yourself -> I have tons of ghetto boards exactly like that. the chips go for a little bit less than that.
can I compare speed of STM32 board with teensy?
depending on nwhich teensy: the avr/m0 teensies are slower, and the m4 teensies are faster.

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Pito
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Re: Welcome & 2 questions

Post by Pito » Sun Jul 09, 2017 1:19 pm

sp9mrn wrote:
Sun Jul 09, 2017 12:58 pm
I think in future to use f103 board as a replacement of tennsy in 2 projects -
1. https://sites.google.com/site/lofturj/p ... eter---rev
2. https://sites.google.com/site/lofturj/c ... r-Graphics
1. and 2. require stm32F407 based board as a minimum.. to be happy and prepared for next updates.. (they use Teensy 3.2 in latest updates)
73
PS: Teensy 3.2 is CortexM4 @72MHz with DSP (no FPU?), F407 is CortexM4f 168MHz with DSP and FPU. Typically the F407 cheapo boards (Black F407/VE/ZE and others) are much larger in size, we do not have such minuscule board as the Teensy handy, a pity :)
Update: I would not expect the both source codes will work on a F407 without some porting effort ..
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Ollie
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Re: Welcome & 2 questions

Post by Ollie » Sun Jul 09, 2017 4:12 pm

@Mac,

I do share Pito's recommendation to go with F407 for these kinds of applications. There are very compact F407 models available that are not much larger that Teensy 3.x. The sad thing is that you cannot insert them into a breadboard. On other hand you have more pins available for peripherals.

My favorite is the blue F407 in Aliexpress

https://www.aliexpress.com/item/New-STM ... 09613.html

It is available under $11, including shipment. Last time when I did order it, it was delivered under two weeks. It comes with the SWD pins soldered. For the other pins, you can use the included male Dupont pins or use your own style. My preference is to use the round machine pins.

For Teensy/F407 comparison, I have done DC motor/encoder controllers in the following combinations
- 2 motors with T3.2
- 4 motors with T3.5
- 6 motors with F407

Based on that experience, I will prefer F407 due to higher performance and more I/O pins. I will still be missing the Teensy libraries that seem to be more robust and functional.

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