Unfortunately, there is no way to differentiate between an optimized gpio write (safe always on the atmega32u4) and an unoptimized write (read-modify-write, dangerous if any other pin on that Port is used in an ISR).
While very quickly polling the tmc registers, I noticed that the moving stepper would do some random extra steps. That can only be explained by the following sequence of actions:
- the spi code reads the PORT register
- ISR toggles the step line, changing the value in the PORT register
- the spi code writes the upated PORT back, resetting the step line to the old state
After making the writes atomic, the stepping issue disappeared and the driver checks also worked correctly
- rename stall*guard to StallGuard (match name with the vendor)
- separate TMC2130 module from EEPROM (they do not need to know about each other at all)
- separate SGTHRS settings from motion - moved to globals like all other "global" parameters
- improved EEPROM storage for SGTHRS
This needs some investigation if it is really possible to push the Registers into PROGMEM. I think it should be possible, but the compiler is currently not collaborating.
It is not critical though as we have lots of free RAM at the moment (I can't believe I wrote this on an AVR project :) )
This is to solve a potential problem while feeding to printer's drive gears - while disengaging the Idler, the Pulley was still rotating to avoid grinding the filament (printer is pulling it).
Other filaments could have moved a bit when the Idler's bearings ran over them while the Pulley was still rotating slowly -> the filament could have been moved into the Selector's path causing trouble (especially when not used in the print).
Therefore, the Idler disengages partially now - moves into an intermediate position between the slots.
Then, the Pulley is completely stopped and after that the Idler does a full disengage like before.
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.
Alex Voinea
VintagePC
Guðni Már Gilbert
Yuri D'Elia
D.R.racer
3d-gussner