Models of the nRF5xxxx SOCs HW peripherals

This repo contains models of the nRF5x HW peripherals and some replacement nrfx HAL functions. When used in combination with the real nrfx, these should enable code meant for the nrfx to run without needing further changes. This includes Zephyr SW.

These models include models of peripherals for an nRF52833 and an nRF5340.
Note that for these models use case an nRF52833 is very similar to other nRF52 series devices , so even if you are developing for another variant in that series these models may be enough for you.
It is the intention that models of other nordic SOCs will be included in the future.

These models library is intended to be used as an extension to the native simulator. If you want to integrate them in another way, please check the section "Using these models without the native simulator" below.

When compiling this component using the provided Makefile (not with Zephyr's build system), the environment variable NRFX_BASE and NATIVE_SIM_PATH must be set. NRFX_BASE must point to the path where nrfx has been cloned. The nrfx must be at least version 3.2.0. So for example, if nrfx has been cloned as:

cd /some_path/nrfx/
git clone git@github.com:NordicSemiconductor/nrfx.git .

NRFX_BASE must be set as:

export NRFX_BASE=/some_path/nrfx/

See the nrfx/hal/README.md for more details.

NATIVE_SIM_PATH must point to the folder where the native simulator has been cloned.

These models can be used directly with Zephyr's nrf52_bsim target. In that case, Zephyr's versions of the nrfx HAL and native simulator will be used by default.

The NRF_RADIO peripheral model uses BabbleSim for the radio environment simulation.

For more information about the HW models, or how to use them without Zephyr please refer to README_HW_models.md

What these models include

Not all SOCs peripherals are modelled yet, and for some of the included peripherals not all features or options are modelled. This is typically the case for HW functionality which is not used by the Zephyr drivers/OS. You can find what features of which peripherals are included so far, and with what approximations in README_impl_status.md. It is certainly possible to expand these models to include the missing peripherals or functionality.

Faithfullness of these models

These models are accurate enough to allow the current Zephyr to run, and its BLE and 15.4 stacks to function. For more details please see the notes on the source files for each peripheral model. In general, functionality is modelled only to the necessary degree as to enable the SW to run, in a manner that is comparable to the real HW.

These models are based solely on the public SOC specifications

They have been developed without any other knowledge and probably contain inacuracies, and defects.

About the ARM processor peripherals

These models do not include the ARM processor peripherals (for ex. the SCB) Even though it would be technically possible to add those, it is considered both risky and unnecessary.

Risky in the sense that adding the equivalent register structures would immediately hide the compiler errors which otherwise would identify the places in which they are used in the embeded code; while at the same time these models would not be precise enough to not require, with very high likelyhood, modification of that part of the embedded code which was using them.

And unnecessary in the sense that the lack of these peripherals can be hidden most of the time if the CMSIS-Core APIs are used instead of direct register accesses, and where these APIs do not provide the necessary functionality, changes to the embedded code would be needed with high likelyhood to trigger sideeffects or so.

Using these models without the native simulator

These models are designed as an extension to the native simulator core/common components. It is in principle still possible to use them without the native simulator, but it will require more work/adaptation than with the previous version of these models. Therefore you may want to consider to:

• Use the previous version, which did not require the native simulator.
• Or to use these newer models, providing a shim/adaptation between the native simulator interfaces the models expect and your execution framework. If so, check the "Integrating these models in another system" section of the HW models README