The temperature and fsensor ISR re-enable interrupts while executing.
However, we still need to protect the epilogue of the ISR so that
the saved return address is not altered while returning.
We hoist the body of the function out of the isr in both cases for
clarity (and to avoid a stray return bypassing the lock/cli), so that
the re-entrant portion is clearly indicated.
This should fix the "STATIC MEMORY OVERWRITTEN" error messages randomly
happening when stepping at high frequency (where either isr is
preempted more frequently).
Factor-out MIN/MAXTEMP [BED/AMB] out of the error message, which is now
built at runtime instead.
Introduce two missing ultralcd functions lcd_setalertstatus and
lcd_updatestatus to handle regular strings.
246272 -> 246084 = 188 bytes saved
Partially revert 285b505c73a54e9af01816e3a614de73ad181851 so that
we ensure heaters are disabled ASAP in case of potential bugs
in the max_*_error functions.
Take advantage of the NTC thermistor found on the Einsy as an additional
safety measure, following the steps of the other MIN/MAXTEMP errors.
Introduce two configurable params AMBIENT_MINTEMP and AMBIENT_MAXTEMP
in the variant defines and set them for the MK3/MK3S to -30/+100
respectively.
AMBIENT_MINTEMP is primarily intended to catch a defective board
thermistor (to ensure MAXTEMP would be properly triggered) and thus the
trigger temperature is set just above the sensing limit and well below
the operating range.
AMBIENT_MAXTEMP is set at 100C, which is instead 20C above the maximum
recommended operating temperature of the Einsy. The NTC thermistor is
located just above the main power connector on the bottom of the board,
and could also help in detecting a faulty connection which can result in
rapid overheating of the contacts.
As for MAXTEMP, we cut power to the heaters, print fan and motors to
reduce power draw. Resume is not possible except by resetting the
printer, since the user is highly advised to inspect the board for
problems before attempting to continue.
In max/min_temp handlers remove the redundant disable_heater() call.
Handlers already need to call Stop(), which will disable all heaters
as the first step.
Fix comments in order to mention that all heaters get disabled.
Use "MAX/MINTEMP BED" correctly in both the LCD and serial.
Remove most of the original complexity from advance_spread.
Instead of accumulating time to be scheduled, plan ahead of time each
eISR tick using the next main interval + an accumulator (eISR_Err),
which keeps everything much simpler.
The distribution of the advance ticks is now using the real LA
frequency, which leaves a bit more time between the last LA tick and
the main stepper isr.
We take advantage of the accumulator to force a LA tick right after the
first main tick, which removes a +/- 1 scheduling error at higher step
rates.
When decompressing, we force 2 steps instead, so that the direction
reversal happens immediately (first tick zeros esteps, second inverts
the sign), removing another +/- 1 error at higher step rates.
