[Any STM32 board] How much time this loop should take ?

Discussion and questions about boards that can run MicroPython but don't have a dedicated forum.
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jimmo
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Re: [Any STM32 board] How much time this loop should take ?

Post by jimmo » Fri May 24, 2019 5:15 am

dhylands wrote:
Fri May 24, 2019 4:46 am
Is your code available someplace (i.e github) that I can build for a 401 board with a known HSE crystal and compare results?
I'm fairly certain (based on other threads, and the values he's quoted that match) that they're working from:

https://github.com/KittenBot/micropytho ... figboard.h

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shazz
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Re: [Any STM32 board] How much time this loop should take ?

Post by shazz » Fri May 24, 2019 3:02 pm

jimmo wrote:
Fri May 24, 2019 5:14 am
Also, maybe a bit of a long shot, but back to the MCO idea -- you said "my logical analyzer doesn't have enough bandwidth I presume". What do you have? Can you set the divider down low enough? Like you just need a pulse counter? Any other dev boards sitting around?
I have this one: https://reference.digilentinc.com/refer ... redirect=1. Specs on the right.
Do you think I can use it to measure out the SYSCLK and HSE frequencies ?

Yeah... The Rigol would be great... time costs more :)
8bits should be enough...

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shazz
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Re: [Any STM32 board] How much time this loop should take ?

Post by shazz » Fri May 24, 2019 3:06 pm

jimmo wrote:
Fri May 24, 2019 5:15 am
dhylands wrote:
Fri May 24, 2019 4:46 am
Is your code available someplace (i.e github) that I can build for a 401 board with a known HSE crystal and compare results?
I'm fairly certain (based on other threads, and the values he's quoted that match) that they're working from:

https://github.com/KittenBot/micropytho ... figboard.h
Yes this is the one.
And this one : https://github.com/KittenBot/micropytho ... ds/MEOWBIT

I'll publish my test code tonight on: https://github.com/shazz/Meowbit-Experi ... xperiments
8bits should be enough...

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jimmo
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Re: [Any STM32 board] How much time this loop should take ?

Post by jimmo » Fri May 24, 2019 3:18 pm

shazz wrote:
Fri May 24, 2019 3:02 pm
I have this one: https://reference.digilentinc.com/refer ... redirect=1. Specs on the right.
Do you think I can use it to measure out the SYSCLK and HSE frequencies ?
Yes....just. In logic analyser mode at 10MS/s. With the /5 divider on MCO, you'll either get 1.6MHz or 2.4MHz. You'll get a pretty messy looking square wave because the pulses will be different widths, but you should at least be able to tell the frequency.

OutoftheBOTS_
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Re: [Any STM32 board] How much time this loop should take ?

Post by OutoftheBOTS_ » Fri May 24, 2019 10:40 pm

I brought the super cheap Hantek DSO5102P scope, it has 2GHz sampling rate and it will read signals up to 100Mhz but the only difference between this model and the big brother model that will read 200MHz signals is the firmware so most people just buy the 100MHz model then update the firmware.

You can see it is pretty cheap https://www.aliexpress.com/wholesale?ca ... k+DSO5102P

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