SPI FrameSize and missing e-hal 1.0

[burrbull]

This is fast impl. Not tested.

cc @everdrone

[tmehr-enqt]

What tests do you think have to be done? I did some quick tests with an spi loopback on a f103 nucleo. That worked. If you assume that the peripheries of the F series are basically all the same I would say it works.

[burrbull]

spi loopback on a f103 nucleo

Have you used embedded-hal API for this?

[tmehr-enqt]

I have now. Still as expected. Still I just tried one configuration of it and not with a real other device, just looping MOSI and MISO. However I'm assuming the the other stuff works just fine. Did you copy this implementation from f4xx too?

[tmehr-enqt]

Maybe also add a allow for static_mut_refs so the spi-slave example doesn't generate warnings?

[burrbull]

Maybe also add a allow for static_mut_refs so the spi-slave example doesn't generate warnings?

I'd replace static mut with something more safe, static-cell or other alternative. PRs are welcome.