Re: Getting started with bare-board development

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 16-11-15 10:38 , Dmitry A. Kazakov wrote:
>
> Typical developing process stages, at least in my area, is like this
>
> 1. Workstation    Simulation time
>    Application
>    [HAL]
>    Mock actuators/sensors
>
> 2. Workstation    Hardware-in-the-loop, real-time
>    Application
>    [HAL]
>    Real/Mock actuators/sensors
>
> 3. Embedded       Target platform
>    Application
>    [HAL]
>    Real/Mock actuators/sensors
>
> Most of developing is done in #1 or #2. Most of testing in #2. #3 is
> limited to final integration tests.

In my domain (subcontractor for embedded SW in spacecraft) we typically 
use only one of the stages 1 and 2, not both. But otherwise our work is 
very similar.

> QEMU et al is not used, because it makes no sense to emulate
> computational hardware when you have Ada, unless you are an OS
> developer.

Or unless you worry about compiler bugs being different in the native 
and cross compilers, or about platform-dependencies introduced by 
mistake in the Ada application. Endian-dependency is easily introduced 
by mistake if the application does a lot of communication with HW. Our 
targets are usually big-endian SPARCs, but workstations are 
little-endian PCs.

Typically we do the final unit-testing runs both on workstations and on 
a target emulator, to settle such worries.

> Whatever OS/platform-dependent parts requiring test under an emulator,
> they are quite minuscule or non-existent if an OS is used.

We rarely (well, never) use an OS in embedded systems. Ravenscar or 
bare-board (zero runtime) is the norm for us. Though, there is a trend 
to have application-independent but domain-specific "execution platform" 
SW components which are like domain-specific OSs and can support various 
applications in this domain.

-- 
Niklas Holsti
Tidorum Ltd, working for SSF
niklas holsti tidorum fi
       .      @       .