fix: SoftwareSerial flush

[gicking]

This PR fixes the following bug:

• SoftwareSerial.flush() returns too early, see issue #2904

Motivation

I maintain a LIN master library for various architectures and serial interfaces. When porting to STM32 I noticed an faulty behavior of SoftwareSerial.flush() (see issue report). This pull request fixes this.

Validation

original:

after bugfix:

See also this sketch SoftwareSerial_flush.zip

[fpistm]

Hi @gicking
Thanks for the PR.
The commit changed SerialUSB.baud() etc. to return the actual CDC line coding
should not be in this PR.

[gicking]

hello Frederic,

sorry for the inconvenience! Unfortunately I am not very experienced with Github - i.e. basically I am just following instructions by ChatGPT ;-)

I understand the issue, but how can I separate the 2 branches now? Also, for my own library development I need a branch that contains both PRs.

For your help thanks a lot in advance!

[fpistm]

Your previous PR is already merged #2892 . So you have to fetch the latest main from the core on your fork then rebase your branch on top of the main branch.
Then do a force push.

Easiest way to do this is:
git remote add upstream https://github.com/stm32duino/Arduino_Core_STM32.git
git fetch upstream
if you already have a main local branch
git reset --hard upstream/main
else
git checkout -b main upstream/main
Finally push on your fork (probably named origin)
git push origin main
Like this your fork is sync with the original repo.

When done you can rebase your branch on top of the main:
git checkout SoftwareSerial.flush
git rebase main
it should drop the commit for the USB.

[gicking]

ok, I did what you asked for. Should I now start a new pull request or is this automatically carried over?

[fpistm]

Hum don't know what you've made but this is not correct.

I've reworked your PR. It is now correct only one commit.
Please do not push again on this branch.

[gicking]

Hum don't know what you've made but this is not correct.

I've reworked your PR. It is now correct only one commit. Please do not push again on this branch.

sorry for the inconvenience! Hope I do it better next time...