Author Topic: A development board for the STM32G081 Cortex M0+ MCU  (Read 927 times)

Andy Brown

  • Administrator
  • Hero Member
  • *****
  • Posts: 283
    • View Profile
    • Andy's Workshop
A development board for the STM32G081 Cortex M0+ MCU
« on: July 13, 2019, 10:22:18 am »
I've recently built a development board for the new STM32G081RBT6 MCU featuring the Cortex M0+ core.



There's a full write up here and a video on YouTube that you can watch.
It's worse than that, it's physics Jim!

ddrown

  • Jr. Member
  • **
  • Posts: 1
    • View Profile
Re: A development board for the STM32G081 Cortex M0+ MCU
« Reply #1 on: July 13, 2019, 04:37:12 pm »
I've recently built a development board for the new STM32G081RBT6 MCU featuring the Cortex M0+ core.

Hello! And thank you for your videos, I'm a fan.

You mention in the video trying to get the ch340 to work on linux with the 9986 vendor ID.  I think there's two choices:

* add the IDs to /sys/bus/usb-serial/drivers/ch341-uart/new_id https://stackoverflow.com/questions/442833/forcing-driver-to-device-match  (this will have to happen every time you boot)

* recompile the ch341 driver with the new vendor ID:  https://elixir.bootlin.com/linux/latest/source/drivers/usb/serial/ch341.c#L82  (this would have to happen every time you upgraded your kernel)

Quote from: Andy Brown
I have no idea how crystals are constructed but I do find it fascinating and it looks a bit like a tuning fork. Does anyone out there know what’s going on in there?

Crystals physically vibrate so the resemblance to a tuning fork is no accident.  There are different shapes used, and this cut is called the tuning fork shape.  "The chief application [of the tuning fork cut] is the 32.768 kHz RTC crystal" - https://en.wikipedia.org/wiki/Crystal_oscillator#Crystal_cuts

Andy Brown

  • Administrator
  • Hero Member
  • *****
  • Posts: 283
    • View Profile
    • Andy's Workshop
Re: A development board for the STM32G081 Cortex M0+ MCU
« Reply #2 on: July 14, 2019, 04:57:06 am »
Thanks for the info about the crystal and also the ch340. I just tried the new_id method and it did work on my Ubuntu VM. I'll give it a try on the Pi later and will also try the permanent fix. Looks promising though.
It's worse than that, it's physics Jim!

Phil

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
Re: A development board for the STM32G081 Cortex M0+ MCU
« Reply #3 on: July 20, 2019, 11:45:06 am »
Interesting comment on mini-B connector. I always heard that the micro-b was more reliable (see: https://electronics.stackexchange.com/questions/18552/why-was-mini-usb-deprecated-in-favor-of-micro-usb ).

though i only ever had 1 micro-b connector fail (none for micro-b). in the end i standardised on micro-b as this is more common though annoyingly, i still have some mini-b's around which i leave the cable plugged in to avoid annoyance.


Andy Brown

  • Administrator
  • Hero Member
  • *****
  • Posts: 283
    • View Profile
    • Andy's Workshop
Re: A development board for the STM32G081 Cortex M0+ MCU
« Reply #4 on: July 20, 2019, 12:41:07 pm »
Interesting comment on mini-B connector. I always heard that the micro-b was more reliable (see: https://electronics.stackexchange.com/questions/18552/why-was-mini-usb-deprecated-in-favor-of-micro-usb ).

though i only ever had 1 micro-b connector fail (none for micro-b). in the end i standardised on micro-b as this is more common though annoyingly, i still have some mini-b's around which i leave the cable plugged in to avoid annoyance.

Hi Phil, the micro-USB connectors that I encountered were fully SMD and had a tendency to rip off the board taking the pads with them if you pushed too hard. I just had a look on ebay and it looks like you can now get micro connectors with through-hole chassis pins. I would be more confident using those. Based on your linked article it seems I need take care inserting and removing mini-B cables if I want them to last a long time.  My favourite is the original full-size B connector but obviously, it's big.
It's worse than that, it's physics Jim!

Phil

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
Re: A development board for the STM32G081 Cortex M0+ MCU
« Reply #5 on: August 13, 2019, 02:38:24 am »
Yes, SMD connectors (micro or mini) are a separate issue. I agree and only use ones with through hole connections.

Also, re: the crystal, it IS a tuning fork. See:

http://www.nkg.com.hk/pdf/NKG-TIT_TuningForkCrystals.pdf