Draft: Dynamic Clock Speed #5
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added 3 commits
February 19, 2020 21:29
- add gitignore - fix sleep_ms timing - write more/better comments
- adds a blink_dynamic_clocks example - rustfmt
dwbrite
commented
Feb 20, 2020
| @@ -42,6 +42,14 @@ enum OscSource { | |||
| External = 2, | |||
| } | |||
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| pub enum CpuFreq { | |||
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I'm uncertain on how much I like the values of this enum, but it does well enough for now.
dwbrite
commented
Feb 20, 2020
| } | ||
| } | ||
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| pub fn mode_to_fbe(&'static mut self) -> Fbe { |
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this function feels... ehh? Maybe just the name is bad.
dwbrite
commented
Feb 20, 2020
| @@ -22,13 +22,13 @@ pub fn delay(n: u64) { | |||
| /// not properly work at all with anything below 5 MHz | |||
| #[inline] | |||
| pub fn sleep_us(microseconds: u32) { | |||
| (0..microseconds).for_each(|_| { | |||
| (0..microseconds).for_each(|_| unsafe { | |||
| let mut inner = crate::mcg::F_CPU / 5_000_000; | |||
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reasoning: accessing static mut is always unsafe, so the only safe thing in here is the loop. I figure this is clearer 🤷♂️
dwbrite
commented
Feb 20, 2020
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This PR mostly focuses on supporting the
PEEmode of the MCG.Previously we could enter
PEE, but not escape it, and our code had no knowledge of its existence.Now, we can allow the k20dx256's clock speeds to dynamically change with a helper function
mcg.set_clocks(mcg::CpuFreq, sim). Additionally, static variables are now supported due to the addition of.bssand.datasections in the linker.In the future, more helper functions should be added for switching between MCG modes.
TODO: documentation and finalizing the API