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.
- It disturbs other stuff that uses WFE/SEV in the system. I ran into
issues with this.
- It needs the irq handler to check for RXTO/TXSTOPPED errors, which makes
it slower.
423: nRF9160 support r=Dirbaio a=diondokter
- Created a chip file with all the peripherals, interrupts and peripheral implementations.
- All peripherals now use an alias for the NS (non-secure) version of the nRF9160 version.
- Implementations of peripherals that don't exist are ignored.
- Most PPI functionality has been stubbed out because the nRF91 has the newer DPPI which is not compatible with the current API. (The channels are also set to not configurable, so they are kinda useless now, but in principle the stubs should never be called)
Co-authored-by: Dion Dokter <dion@tweedegolf.com>
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).
