The previous commits by @leptun were correct but there has been one call to Disable axis (and TMC) hidden in `InitMovement`.
Therefore `InitMovement` has been split into 2 separate functions - one is there to allow the original full axis reinit, but the other `InitMovementNoReinitAxis` now only prepares a move without reiniting the TMC driver.
This approach seems to have the benefit of fixing the Idler creep over time.
The disadvantage is the fact, that setting StallGuard threshold is no longer called. We may need to add a special piece of code to handle/apply SGTHRS change at runtime like before.
With PWM_FREQ=2 (fPWM = 2/512 fclk), the idler parked current was quite high since the setting was not actually respected (scientifically tested using hand). In order to allow lower current regulation in stealthchop, TBL and PWM_FREQ need to be adjusted. The lower both of these values, the better. Since TBL affects both stealthchop and spreadcycle, I chose to only modify PWM_FREQ.
This new PWM_FREQ results in half the previous stealthchop PWM frequency and also halves the low current limit (so if previously the minimum achievable current was 300mA, now it would be 150mA). I confirmed that this setting works correctly on a 24V supply. There is no audible noise from stealthChop PWM and the hold current is indeed reduced now (again, scientifically tested using my hand).
This PR is just about tuning the intermediate Idler positions so that the filament gets relieved from the Pulley safely while the Extruder gears take over and the activeSlot+1 filament is not affected by its Idler bearing.
On a test bench filament was creeping about 0.5mm per Toolchange.
Changing the intermediate position from exact middle into 3/4 practically elliminated the creep. We can play with these constants more if necessary in the future.
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 :) )
Guðni Már Gilbert
Alex Voinea
D.R.racer
VintagePC
Yuri D'Elia
3d-gussner