Add support of STM32U0xx series

[doctek]

Board description (please complete the following information):

• Name: Generic STM32U073KB
• Link to all relevant information: Reference is to the STM data for the part. Nothing special here.
  • Documentations
  • Schematics
  • Where this hardware can be purchased

• ...

Note that user can add a STM32 based board following this wiki

Any contribution is welcome, so do not hesitate to submit a PR.

All new variant request will be moved to [New Variant] request list #722 and the related issue will be closed.

[fpistm]

Hi @doctek
Before adding the support of the generic STM32U073, the STM32U0xx series have to be added.

[doctek]

Thank you for your improvements to my request, fpistm! I appreciate it greatly.
Any idea on a time line for this?
Thanks!

[fpistm]

Hi @doctek
I've made a first part of the job this morning using a script dedicated to add new stm32 series.
I've got the Blink working on a Nucleo U083RC.
I will do the PR this afternoon for basic support feel free to test on your side and give your feedback.

[doctek]

This is amazing! I can' imagine how you were able to do this so quickly!!
Of course I will gladly test your work on my STM32U073KB. I've read the instructions on Using the GIT Repository and I'm pretty confident I can follow that. The only thing I'm not sure of is what version to clone. What is the new version number?
Thank you for your hard work and rapid response!

[fpistm]

You can fetch the PR or use my branch on my fork.

[doctek]

Obviously, I'm not the GIT pro that you are, so let me make my question very clear.
In the wiki entry for "Using git repository", Step 3 says I should clone the new version using this command:
git clone https://github.com/stm32duino/Arduino_Core_STM32.git
What should I put in for ?

Thanks, sorry for being stupid.

       -jim

[doctek]

Hmm. That last posting didn't come through very clearly. I'm very sorry for that, although I don't know exactly what caused it.
The wiki reference should have been git clone [https://] [github.com/] [stm32duino/Arduino_Core_STM32.git] [<[version]>]
Hopefully, I've broken the command up enough that it will post correctly.
My question is: What should I put in for [version]?

Thanks and sorry for messing up the last post and not noticing it!
-jim

[fpistm]

Hi @doctek
Sorry was OoO yesterday. Version is the cire version. So 2.8.1.

[doctek]

Following the instructions, I deleted the 2.8.1 files that I had and cloned the latest version.
When I started Arduino, I do not see any STM board choice that is for the U073. What am I missing?
Looking at the git files for 2.8.1, I don't see any reference to merging #2495. Makes ;me think that I am not cloning the correct version. Again, I'm not a git power user! Can you tell me what I'm doing wrong?
Thanks for your patience!
-jim

[fpistm]

PR #2495 is not merged.
As stated you can:

• Clone my fork and checkout my branch:
  https://github.com/fpistm/Arduino_Core_STM32/tree/STM32CubeU0_addition

• Fetch only the PR in the original repo. For this I have a git alias in my .gitconfig:

[alias]
    pr = "!f() { git fetch -fu ${2-origin} refs/pull/$1/head:pr/$1 && git checkout pr/$1; }; f"

when added you can simply do on the git repo:
git pr 2495

[doctek]

I'm trying real hard to follow your instructions.
Here's what I did. You'll have a good laugh at my git newbee errors!
First, I tried to clone your repository. I deleted 2.8.1 and issued this command:
git clone https://github.com/fpistm/Arduino_Core_STM32
I tried to clone the complete link you gave https://github.com/fpistm/Arduino_Core_STM32/tree/STM32CubeU0_addition, but that wouldn't work.
Then I modified the file .git/config to add the [alias] for pr.
Then I issued this command:
git pr 2495
Result:
fatal: couldn't find remote ref refs/pull/2495/head

I have no idea what to try next. Thank you for your patience.

[doctek]

Actually, I did
git clone https://github.com/fpistm/Arduino_Core_STM32 2,8,1
The rest is correct.

[doctek]

Progress! This command did it.
git clone --single-branch --branch STM32CubeU0_addition https://github.com/fpistm/Arduino_Core_STM32.git 2.8.1
I fired up Arduino and there is now a generic STM32U0 board type!
Of course, it's never quite that simple. I'm using an STM32U073KBU, not any of the STM32U73R versions listed. I think I can bend one of these enough to let me test the code. I'll keep you posted.
Again, many thanks for your support!

[doctek]

OK, I did some more poking around in variants directory and found the U073KBU variant! I think a little work on the boards file will get this working for now.

[fpistm]

git pr alias is to fetch a PR on the official repo. So you have to clone the official repo not my fork. Anyway cloning my fork do the same and it is easy to fetch update.

[doctek]

Happy Dance time! My STM32U073KBU board blinks a led!
Here's what I had to do:

• must use arduino-cli. The Arduino ide doesn't see any 073 boards except the R versions. Efforts to add names to the boards.txt file didn't work.
• must add ldscript.ld to the variants file for the U073 boards.
• must update STM32CubeProgrammer to the latest version to get the loader.
  With that done, it works! Can't wait for it to be properly integrated into Arduino, but I can keep working.
  Thank you for your excellent work!
  -jim

[fpistm]

• must use arduino-cli. The Arduino ide doesn't see any 073 boards except the R versions. Efforts to add names to the boards.txt file didn't work.

You probably need to clean up Arduino IDE cache.

[doctek]

Clearing the cache is a good suggestion. Googling for how to do that offered only one useful suggestion: remove ard* files from /tmp. So I tried that, but the new boards still do not appear, although I have added them to the boards.txt file. Obviously, there are additional files cached by Arduino, since it knew what sketch I was editing even after I deleted the ard* files and restarted Arduino.
Could you be so kind as to tell me how to purge the Arduino cache and make the board types appear?
Thank you!

[doctek]

I found more about clearing the Arduino cache. Using the sledge hammer approach of deleting the ~/.config/arduino-ide file and restarting did the trick. Now I see the U073K entries. I expect they will work as desired.
Is there a gentler way to clear the cache?
Thanks!

[fpistm]

This is the method I used. An issue is opened on Arduino IDE to fix this issue.

[doctek]

That did it! I can program mySTMU073K parts from the Arduino IDE.
Thanks again for the excellent support and patient assistance.
-jim

[fpistm]

For ref:
arduino/arduino-ide#1030 (comment)