Starting the sampling task prior to starting the SAADC peripheral can lead to unexpected buffer behaviour with multiple channels. We now provide an init callback at the point where the SAADC has started for the first time. This callback can be used to kick off sampling via PPI.
We also need to trigger the SAADC to start sampling the next buffer when the previous one is ended so that we do not drop samples - the major benefit of double buffering.
As a bonus we provide a calibrate method as it is recommended to use before starting up the sampling.
The example has been updated to illustrate these new features.
613: Rust stable support r=Dirbaio a=Dirbaio
This PR adds (limited) stable Rust support!
The drawbacks are:
- No `#[embassy::task]`, `#[embassy::main]`. (requires `type_alias_impl_trait`). You have to manually allocate the tasks somewhere they'll live forever. See [example](https://github.com/embassy-rs/embassy/blob/master/examples/nrf/src/bin/raw_spawn.rs)
- No async trait impls (requires GATs). Note that the full API surface of HALs is still available through inherent methods: #552#581
- Some stuff is not constructible in const (requires `const_fn_trait_bound`), although there's an (ugly) workaround for the generic `Mutex`.
So it's not that bad in the end, it's fully usable for shipping production-ready firmwares. We'll still recommend nightly as the default, until GATs and `type_alias_impl_trait` are stable.
Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>
591: PWM WS2812B example and flexible sequence config r=Dirbaio a=huntc
I've permitted the PWM sequences to be mutated on stopping the PWM by associating them with a new `SingleSequencer` structure. This is so that we can perform effects on the LEDs (and other use-cases, I'm sure!). The example has been updated to illustrate the use of this by flashing a WS2812B LED.
There's also a `Sequencer` structure for more sophisticated PWM interactions, along with a `pwm_double_sequence` example to illustrate.
These changes should make it possible to attain all of the nRF PWM functionality available.
Co-authored-by: huntc <huntchr@gmail.com>
This approach owns the sequence buffers which, while introducing an extra move, it eliminates the need to guard the lifetime of the sequence buffer. Given ownership, the buffer will be retained until the PWM sequence task is stopped.
Demonstrates how to set the colour of a WS2812B to blue using PWM, and the use of multiple sequences along with their own config. This required an API change.
I had introduced a small bug in my last PR where I assigned the sequence before stopping the PWM. I now stop the PWM before doing that now.
Also, corrected a math comment.
Sequences are now passed in via the start method to avoid having to stop the PWM and restart it. Sequences continue to be constrained with the same lifetime of the Pwm object itself. The pwm_sequence example has been extended to illustrate multiple sequences being passed around.
Unsafe is not required here given that all futures are required to live longer than their global peripheral instances. There are other occurrences of unsafe being used on new that should be removed. I started to do that but then went down a bit of a rabbit hole.
539: nrf: async usb r=Dirbaio a=jacobrosenthal
Frankensteined together from this old pr https://github.com/embassy-rs/embassy/pull/115 and nrf-usdb
~Doesnt currently work..~
Co-authored-by: Jacob Rosenthal <jacobrosenthal@gmail.com>
544: Introduces split on the nRF Uarte r=Dirbaio a=huntc
A new `split` method is introduced such that the Uarte tx and rx can be used from separate tasks. An MPSC is used in an example to illustrate how data may be passed between these tasks.
The approach taken within the `Uarte` struct is to split into tx and rx fields on calling `Uarte::new`. These fields are returned given a call to `Uarte::split`, but otherwise, if that call isn't made, then the API remains as it was before.
Here's a snippet from a new example introduced:
```rust
#[embassy::main]
async fn main(spawner: Spawner, p: Peripherals) {
// ...
let uart = uarte::Uarte::new(p.UARTE0, irq, p.P0_08, p.P0_06, NoPin, NoPin, config);
let (mut tx, rx) = uart.split();
// ...
// Spawn a task responsible purely for reading
unwrap!(spawner.spawn(reader(rx, s)));
// ...
// Continue reading in this main task and write
// back out the buffer we receive from the read
// task.
loop {
if let Some(buf) = r.recv().await {
info!("writing...");
unwrap!(tx.write(&buf).await);
}
}
}
#[embassy::task]
async fn reader(mut rx: UarteRx<'static, UARTE0>, s: Sender<'static, Noop, [u8; 8], 1>) {
let mut buf = [0; 8];
loop {
info!("reading...");
unwrap!(rx.read(&mut buf).await);
unwrap!(s.send(buf).await);
}
}
```
Co-authored-by: huntc <huntchr@gmail.com>
A new `split` method is introduced such that the Uarte tx and rx can be used from separate tasks. An MPSC is used to illustrate how data may be passed between these tasks.
542: nrf/gpiote: remove PortInput, move impls to Input/FlexPin. r=Dirbaio a=Dirbaio
`PortInput` is just a dumb wrapper around `Input`, it has no reason whatsoever to exist. This PR moves the `wait_for_x` functionality to `Input` directly.
It also adds it to `FlexPin` for completeness and consistency with `Input`.
(The reason `PortInput` exists is a while ago `GPIOTE` was an owned singleton that you had to initialize, so `PortInput::new()` would require it to enforce it's been initialized. This doesn't apply anymore now that GPIOTE is "global")
Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>
As per Tokio and others, this commit provides a `poll_flush` method on `AsyncWrite` so that a best-effort attempt at wakening once all bytes are flushed can be made.
The constructors themselves are not strictly unsafe. Interactions with DMA can be generally unsafe if a future is dropped, but that's a separate issue. It is important that we use the `unsafe` keyword diligently as it can lead to confusion otherwise.
486: Pwm ppi events r=Dirbaio a=jacobrosenthal
More PWM yak shaving. I was going to do some safe pwm ppi events stuff but I just dont think it fits this api design.. ppi is just very low level, im not sure how safe it will be in general
* first we should probably have borrows of handlers for ppi with lifetime of the peripheral? hal does eb4ba6ae42/nrf-hal-common/src/pwm.rs (L714-L716)
* in general having access to tasks can put the state in some configuration the api doesnt understand anymore. for `SequencePwm` ideally id hand you back either only seq_start0 or seq_start1 because youd only use one based on if your `Times` is even or odd.. but again we only know that with this api AFTER start has been called. I dont think were ready for typestates
SO I figured why not add the pwm ppi events but make them unsafe and commit this example since I started it.
Somewhat related drop IS removing the last duty cycle from the pin correctly, but stop DOES NOT..the only thing that sets the pin back is pin.conf() as far as I can tell, so I tried to document that better and got rid of stop for the `SimplePwm` again since that doesnt need it then. However its ackward we dont have a way to unset the pwm without setting a new sequence of 0s, or dropping the peripheral
Co-authored-by: Jacob Rosenthal <jacobrosenthal@gmail.com>
It is basically impossible to directly convert that example to a sequence for various reasons. You cant have multiple channels on same buffer with one sequence instance for starters, also at that clock rate and max_duty 1 period is far longer than the 3ms it was using, which would require using a new max_duty and thus require regenerating the sine table which makes it not representitive of the original example anymore
455: simple_playback api from nrf sdk r=Dirbaio a=jacobrosenthal
Port of the nrf_drv_pwm_simple_playback call from the nordic sdk that allows you to set up a sequence to play across leds with no interaction necessary using the 'shorts' registers to trigger looping sequences
Co-authored-by: Jacob Rosenthal <jacobrosenthal@gmail.com>
Rustflags apply to ALL the crates in the graph, while we only need
them for the toplevel crate which is the only one getting linked.
Rustflags are not equal for all crates, this caused cargo to re-build the
same dependency crate multiple times uselessly. After this change, deps
are reused more, making builds faster.
Note that this only applies when sharing the target/ dir for multiple crates
in the repo which is not the default.
- Removed ConfigurableChannel and added capacity numbers to the channels
- Replaced the PPI api with a new one using the DPPI terminology (publish & subscribe)
- Updated all tasks and event registers for DPPI
Implements continuous sampling for the nRF SAADC and also renames `OneShot` to `Saadc`. The one-shot behaviour is retained with the `sample` method and a new `run_sampler` method is provided for efficiently (i.e. zero copying) sampler processing. A double buffer is used for continuously sampling, which wlll be swapped once sampling has taken place.
A sample frequency is provided and will set the internal timer of the SAADC when there is just the one channel being sampled. Otherwise, PPI will be used to hook up the TIMER peripheral to drive the sampling task.
One-shot mode now permits the sampling of differential pins, and the sampling of multiple pins simultaneously.
A new ChannelConfig structure has been introduced so that multiple channels can be configured individually. Further, the `sample` method now accepts a buffer into which samples are written.
Along the way, I've reset some default configuration to align with Nordic's settings in their nrfx saadc driver. Specifically, the channel gain defaults to 6 (from 4) and the time defaults to 10us (from 20us).
Previously the cargo configurations of all of the example projects had
`build-std = ["core"]`, which forces compilation of `core` as a
code-size optimisation. However, this is strictly unnecessary and will
currently break for users who do not use `rustup` directly (e.g. nix
users).
An MPSC inspired by Tokio and Crossbeam. The MPSC is designed to support both single and multi core processors, with only single core implemented at this time. The allocation of the channel’s buffer is inspired by the const generic parameters that Heapless provides.
