try to use fugit::Duraction for CountDown::Time

[burrbull]

Not for SysTick for now Use 1 microsecond as minimal timeout for SysTick Counter

This PR lets to use fugit units for timer including values bigger then 1 second.
Sampling of timer (time of 1 tick) now can be set in by FREQ generic constant.

[dbrgn]

Typo: Duraction -> Duration (also in the PR title). Maybe add "instead of a frequency" to the line?

[burrbull]

Thanks

[dbrgn]

All deprecated what? 🙂

[burrbull]

Don't pay attention. Accidentally deleted in previous PR

[burrbull]

cc @andresv I've tried to implement atat::Clock also. Is this correspond to your vision?

[andresv]

@burrbull yes I think currently this is what must be done, embedded-hal did not have suitable traits therefore atat::Clock was born.

It is a little bit inconvenient to use atat::Clock on embedded platforms that do not use fugit based timing (almost all HALs at the moment) because essentially you have to make a new type and impl Clock for that which probably involves reading timer counter from a specific register using unsafe.

Also last time I read that CountDown is maybe thrown away from embedded-hal v1.0, so I guess we do not have anything stable for a long time.

[burrbull]

It is a little bit inconvenient to use atat::Clock on embedded platforms that do not use fugit based timing (almost all HALs at the moment) because essentially you have to make a new type and impl Clock for that which probably involves reading timer counter from a specific register using unsafe.

Before port implementation to other HALs (and merge to this one), I must be sure it works as expected (I'm not sure it is so).

[andresv]

Do you mean that fugit itself is maybe not suitable or what do you mean by that?

[burrbull]

Do you mean that fugit itself is maybe not suitable or what do you mean by that?

I mean I need someone test this and told me if I made mistake.
And yes, I still not sure about fugit.

[burrbull]

Now it just adds new structs, so no breaking changes.

[therealprof]

Very nice!

bors r+

[bors]

Build succeeded:

• ci (stm32f401, stable)
• ci (stm32f405, stable)
• ci (stm32f407, stable)
• ci (stm32f410, stable)
• ci (stm32f411, stable)
• ci (stm32f412, stable)
• ci (stm32f413, stable)
• ci (stm32f415, stable)
• ci (stm32f417, stable)
• ci (stm32f423, stable)
• ci (stm32f427, stable)
• ci (stm32f429, stable)
• ci (stm32f437, stable)
• ci (stm32f439, stable)
• ci (stm32f446, stable)
• ci (stm32f469, stable)
• ci (stm32f479, stable)
• Rustfmt