We cannot get a constexpr definition of the register addresses, and any
reinterpret cast is currently illegal for a constexpr in c++17.
Change the SPI0, TIFR and TIMSK to volatile const pointers instead.
SPI0 has volatile members instead of marking the entire struct as
volatile, which is probably not a good idea as it technically drops the
volatile from the original pointer.
we shall think about the Pulley as well, it looks like it should get its
own class just like Idler and Selector as it behaves very similarly in terms
of stepping and error checking
The parameter config::AxisConfig::uSteps was supposed to be
microstepping resolution, but it's instead being used as the driver's
MRES directly.
To avoid a runtime conversion, rename the field to mRes and define a new
enum listing all the possible (and valid) microstepping resolutions.
This simplifies the code and makes clear the stepsPerUnit scale.
Assign correct stepsPerUnit to all axes as a result, including working
limits.
Introduces a nasty hack to forcefully write into the constexpr SPI descriptor's registers
(which is the correct way in ASM, but kind of cumbersome in C++ now)
To keep these methods efficient no member should be accessed away.
That's the reason MotorParams is passed explicitly for each.
Mark all stepping methods as static.
Change the TMC2130 class after starting to review the Motion API.
Move motor mode handling and stepping to this module.
Create a new MotorParams class for compile-time settings (currently
pins, direction, microstepping).
Keep other settings separate, so that we can pass constexpr expressions
while stepping and still get 1 instruction without overhead.
Alex Voinea
Yuri D'Elia
D.R.racer