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
- 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).
