Andy's Workshop Forums

General Category => Hardware projects => Topic started by: Andy Brown on July 13, 2019, 10:22:18 am

Title: A development board for the STM32G081 Cortex M0+ MCU
Post by: Andy Brown 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.

(http://andybrown.me.uk/wp-content/images/stm32g081dev/stlink.jpg)

There's a full write up here (http://andybrown.me.uk/2019/07/08/stm32g081dev) and a video on YouTube (https://youtu.be/v8Xii3Ykvgw) that you can watch.
Title: Re: A development board for the STM32G081 Cortex M0+ MCU
Post by: ddrown 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
Title: Re: A development board for the STM32G081 Cortex M0+ MCU
Post by: Andy Brown 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.
Title: Re: A development board for the STM32G081 Cortex M0+ MCU
Post by: Phil 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.

Title: Re: A development board for the STM32G081 Cortex M0+ MCU
Post by: Andy Brown 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.
Title: Re: A development board for the STM32G081 Cortex M0+ MCU
Post by: Phil 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