The binary size impact is moderate, like 18 bytes plus
4 bytes per endstop defined.
The story is a follows:
The endstop logic can be used to use a touch probe with PCB
milling. Connect the (conductive) PCB surface to GND, the
spindle/mill bit to the signal line, turn the internal pullups
on and there you go.
However, doing so with pullups always enabled and while milling
under (conductive) water showed polished mill and drill bits to
become matte after a few hours of usage. Obviously, this small
0.5 mA current from the pullup resistors going through the
rotating mill bit is sufficient to get some spark erosion going.
That's bad, as spark erosion happening also means tools become
dull faster than neccessary.
With this patch, pullups are turned on while being used, only,
so this sparc erosion should go away.
This enhances encapsulation.
An attempt to initialise only the timers in use was abandoned.
This isn't only unneccessary, as pins are still in normal
operation mode unless their bits in TCCR0A/TCCR2A/... are set,
even with the timer behind the pins running, it's also at least
tricky to sort pins and their timer bits at compile time. Doing
the sorting at runtime would cause additional binary size.
- ATmega32U timer 4 register handling differs from other AVRs:
Change heater.c and mendel.c.
- LUFA USB recognition expanded in Makefile.
- Add section for __AVR_ATmega32U4__ in arduino.h.
Instead of converting them to absolute first, then back to
relative and having all the fuzz with working on the queue's
start vs. working at the queue's end, mark a movement as relative
and use this directly.
This includes:
- Initialize them in mendel.c.
- While running, switch the pin only.
- Sort mendel.c the same order as in pinio.h.
- Remove the requirement of a parameter for this flag, like
it's with all other flags.
This required to also introduce dda_init() and re-adjust the
number of accelerating steps a bit.
Goal of this is to make look-ahead possible by just reducing
the number of deceleration steps and acceleration steps of
the next move. dda->c and dda->n no longer go down to their
initial values, then.
Also, quite a number of variables in the dda struct are used only when
the dda is live, so there is no need to store that for each
movement of the queue.
This costs 2 bytes of ram, but saves 60 bytes of flash. Doing so
also eliminates the need to disable interrupts while clearing flags
in the ifclock macro.
Conflicts:
clock.c
timer.c
timer.h
All other firmwares set them to zero -> no internal pullup resistor,
as they counter-work to the design of the electronic endstops.
However, in conjunction with mechanical endstops, they're very practical.
Markus Hitter
David Forrest
Jim McGee
Michael Moon
Ben Jackson
Stephan Walter
Markus Amsler