[Arm-netbook] Arduino, ARM microcontrollers, and analog

[David Niklas]

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Hello list,
Recently I and luke exchanged a set of emails on the above topic and luke
suggested to bring the discussion on list. I originally sent it off list
to avoid adding more off topic discussion, but luke advised that:
"It's very diverse, and concerns the *development* of laptops - and
hardware."

So, here's the refresher (I'm not going to quote all of it because it's
not worth it to you or anyone).
There's still room for much discussion on the subject.

luke, if my attempted condensed form does not capture your intentions
perfectly be sure to send my terminal SIG666 and scream loudly. ;-)

> As a direct result of Trump's tariffs I find myself needing to buy
> myself a few uCs now instead of later [1].
> The problem is, though I do know a lot about electricity I know
> relatively little about integrated circuits. I've got a long road ahead
> filled with lots of reading to get there.
>
> If you have any other suggestions, I'm also listening.

Luke pointed out that "pricing on things like STM32Fs is so low, it's not
worth worrying about."
I answered, "Call me pathetic, but 25% is still 25% no matter the
starting cost. There's also the concern that if the uC demand reduces
then the price will rise as the companies strive to make up for lost
profits and then demand will further drop... and development will
stall..."




Luke recommended the STM32F lineup supported by lubopencm3, which I
already had my eyes on, and said that the AVR lineup was yucky.

Since then I discovered that there is a third choice of uCs. They use
the LX6 32bit microprocessor at 160-240MHz, which is pretty fast.
Here's wikipedia:
https://en.wikipedia.org/wiki/ESP32
Lots of links to docs here: http://esp32.net/
Git hub has lots of code: https://github.com/espressif
Official docs: https://docs.espressif.com/projects/esp-idf/en/latest/

What's strange about them is that they have not released the ISA docs yet
for the LX6 core in spite of GCC 5.2 supporting it. GCC 7 and 8 support
is experimental.
https://github.com/espressif/crosstool-NG/pull/2
https://esp32.com/viewtopic.php?f=2&t=6477
https://www.esp32.com/viewtopic.php?t=293
I did double check that this is still the case:
https://esp32.com/viewtopic.php?f=5&t=11908




My intentions in purchasing are two fold: I'll probably be using a uC for
a keyboard on my own laptop, and I had hoped to build an Opensource
oscilloscope/logic analyzer several years from now. This is not to
mention the usefulness which uCs can be in general.

Luke pointed out, "that's a different matter: that's pretty hard-core ADC
territory. 100mhz and above, with 16-bit accuracy and above:
realistically, only Analog Devices covers that ground, and a standard
low-cost uC would not in any way be able to cope with the amount of data
generated."

That exact use case has a large following (179 articles on hackaday
alone): https://hackaday.com/tag/oscilloscope/
And here's a really cool project using SDRAM:
https://hackaday.com/2016/07/19/hackaday-prize-entry-the-cheapest-logic-analyzer/

Here are some "professional" ones.
ATXMEGA32A4U uC powered:
https://www.kickstarter.com/projects/920064946/xminilab-portable-oscilloscope
https://www.kickstarter.com/projects/920064946/xprotolab-portable

Here are some not using uCs:
Xilinx spartan3A FPGA:
https://www.kickstarter.com/projects/751733865/smartscope-reinventing-the-oscilloscope
Luke kindly pointed out that this is FPGA powered:
https://www.kickstarter.com/projects/201461162/unoprologic2-ultra-low-cost-open-source-oscillosco
MIPS arch (has higher clocks then your typical uC):
https://www.kickstarter.com/projects/oscope/mutliplatform-multi-os-oscilloscope-signal-generat

Lastly and I've no idea what powers this one, even after reading the
datasheet's summery:
https://www.kickstarter.com/projects/342199468/openscope-instrumentation-for-everyone







If you've got anything to add, as always, thank you,
David


> [1]: I get it, tariffs work for steel, but not so well for computers, as
> bunnie explains it's a much much more dangerous game:
> https://www.cnn.com/2019/02/12/business/us-steel-mill/
> https://www.nasdaq.com/article/nucor-to-build-135-billion-steel-plate-mill-in-kentucky-cm1121964
> https://www.bunniestudios.com/blog/?p=5349
> I read that they would affect SBCs on linuxgizmos and guessed they'd
> affect uCs before too long also:
> http://linuxgizmos.com/introduction-to-catalog-of-125-linux-hacker-boards/
> What's really strange is that he's targeting the maker community vs.
> only the big companies like ASUS, i.e. he's not set a small quantity
> limit on the tariffs (though big companies would probably try to
> maneuver into such an exception).
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