fix: core was not recognized and 1-step lock did not work

[ckrenslehner]

The Core was not recognized properly, and the 1-step lock did not work, because the match was wrong.

@Dirbaio had the idea of using the build feature flags instead of reading the register for identifying the Core.
How would I specify such features for CM7 and CM4 for e.g. stm32h745?

[Dirbaio]

you can add here another line

embassy/embassy-stm32/build.rs

Line 1922 in 443ffd8

cfgs.push(format!("{}_{}", &chip_name[..chip_name.len() - 2], core));

like this

cfgs.push(format!("core_{}", core));

so you can do cfg(core_cm4)

[ckrenslehner]

Ok thanks I will add the cfgs

[Dirbaio]

Have you seen #4092 ? seems you guys are working on the same thing.

[ckrenslehner]

I just updated this, as this is a stepping stone to #4116