Before, endstops were checked on every step, wasting precious time.
Checking them 500 times a second should be more than sufficient.
Additionally, an endstop stop now properly decelerates the movement.
This is one important step towards handling accidental endstop hits
gracefully, as it avoids step losses in such situations.
As a sample application, use it in queue_empty().
There's also ATOMIC_BLOCK() coming with avr-libc, but this requires
a C99 compiler while Arduino IDE insists on running avr-gcc in C89 mode.
Teacup handles motor on/off automatically and if your
intention is to stop the printer, M0 is appropriate (and
conforming with the NIST G-code standard).
That said, M84 is kept as a synonym for M2 to enhance compatibility
with slic3rs default end-G-code.
This means, modify existing code to let the lookahead algorithms
do their work. It also means to remove some unused code in
dda_lookahead.c and reordering some code to make it work with
LOOKAHEAD undefined.
We have now Makefile-AVR - AVR specific stuff - and
Makefile-common - common build instructions.
This effort is the begin of preparing Teacup for ARM targets.
To build the target, copy or link Makefile-AVR or Makefile-ARM
(depending on your target) to Makefile.
Powering on even with a heater set to zero doesn't work, as
temperature driven heaters are set to zero all the time. So,
the PSU was running all the time.
The bug was introduced with 569e3d504aafd1ffc8b279b5d7092970cef72287
The requirement was simply neither obvious nor intuitive. Drawback
is, the indices of temperature sensors can now differ from these
of the heaters. That's easier to recognize for newbies, though.
It was replaced a few weeks ago by usb_serial, which is a single
file solution, so no submodules are required. Also, a recent
Teensy user reported usb_serial to work much better.
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.
Files for trying splitting up paths into sub-paths:
acceleration - constant speed move - deceleration
This could allow to calculate acceleration/deceleration with only
16 bit integers, greatly speeding up the step interrupt.
It should also make look-ahead more simple and allow to round out
corners with curves. Rounding corners is mandatory when keeping
movement speed at corners.
For trying, run ./alg2.make, it'll run on the host computer and
should show a graph.
Markus Hitter
David Forrest
Michael Moon