Add support for true random number generator (RNG) peripheral #224
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- Adds `RngExt` trait to constrain and enable RNG peripheral with HSI48 clock - Implements state machine with `Rng<Stopped>` and `Rng<Running>` types - Provides blocking and non-blocking read methods for 32-bit random values - Implements `TryRngCore` from `rand` for interoperability with rand traits - Includes error handling for seed and clock error conditions
| use crate::{rcc::Rcc, stm32::RNG}; | ||
| use core::{fmt::Formatter, marker::PhantomData}; | ||
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| pub enum RngError { |
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Would you mind implementing defmt::Format when the defmt feature is enabled?
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I've added a conditional impl of defmt::Format
| let status = unsafe { (*RNG::ptr()).sr().read() }; | ||
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| // Check if the seed or clock error bits are set | ||
| if status.seis().bit_is_set() { |
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I do not know about G4, but I believe for the H5 you have to reset the bit to ensure the peripheral is restored to a valid state. See stm32-rs/stm32h5xx-hal#37
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I've added a seed_error_recovery() method that performs the recovery sequence from a seed error. The clock error resets itself when the clock condition (fRNGCLOCK > fHCLK/32) is satisfied per RM0440.
This requires the caller calls seed_error_recovery() if a read returns RngError::SeedError. I considered making reads self-recover - but I figured in some cases it would be useful to know there was a seed error so I've left it explicit.
Cargo.toml
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| @@ -20,6 +20,7 @@ stm32-usbd = { version = "0.7.0", optional = true } | |||
| fixed = { version = "1.28.0", optional = true } | |||
| embedded-io = "0.6" | |||
| stm32-hrtim = { version = "0.1.0", optional = true } | |||
| rand = { version = "0.9", default-features = false } | |||
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Should we use rand_core instead of rand?
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I changed to rand_core in dependencies, and moved rand to dev-dependencies which is required for the example.
….3 RNDATA description
RngExttrait to constrain and enable RNG peripheral with HSI48 clockRng<Stopped>andRng<Running>typesTryRngCorefromrandfor interoperability with rand traits