From 34a1ce483737832fea5651f7c2d2fc9838c19414 Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Wed, 12 Jan 2022 23:43:11 -0500 Subject: [PATCH] tmc2130: Rework current selection to prefer vsense=1 It is preferable to program the tmc drivers with an irun (or cs) setting near 31, as otherwise the driver may have reduced microstep precision. It was possible for the driver to be programmed with irun=16 or irun=17 when it could have been configured with irun=31 with vsense=1 instead. This would occur on tmc2130/tmc2208/tmc2209 drivers for values around 0.900 to 1.000 amps (when using a typical sense_resistor settings of 0.110 Ohms). Change the code to prefer using vsense=1 to avoid this issue. Signed-off-by: Kevin O'Connor --- docs/Config_Changes.md | 6 ++++++ klippy/extras/tmc2130.py | 41 +++++++++++++++++++++------------------- klippy/extras/tmc2660.py | 25 ++++++++++++++++-------- 3 files changed, 45 insertions(+), 27 deletions(-) diff --git a/docs/Config_Changes.md b/docs/Config_Changes.md index e9bcd120..ead2445c 100644 --- a/docs/Config_Changes.md +++ b/docs/Config_Changes.md @@ -8,6 +8,12 @@ All dates in this document are approximate. ## Changes +20220116: The tmc2130, tmc2208, tmc2209, and tmc2660 `run_current` +calculation code has changed. For some `run_current` settings the +drivers may now be configured differently. This new configuration +should be more accurate, but it may invalidate previous tmc driver +tuning. + 20211230: Scripts to tune input shaper (`scripts/calibrate_shaper.py` and `scripts/graph_accelerometer.py`) were migrated to use Python3 by default. As a result, users must install Python3 versions of certain diff --git a/klippy/extras/tmc2130.py b/klippy/extras/tmc2130.py index c6a54561..f2142d26 100644 --- a/klippy/extras/tmc2130.py +++ b/klippy/extras/tmc2130.py @@ -116,30 +116,33 @@ class TMCCurrentHelper: vref = 0.32 if vsense: vref = 0.18 - cs = int(32. * current * sense_resistor * math.sqrt(2.) / vref - - 1. + .5) + cs = int(32. * sense_resistor * current * math.sqrt(2.) / vref + .5) - 1 return max(0, min(31, cs)) - def _calc_current(self, run_current, hold_current): - vsense = False - irun = self._calc_current_bits(run_current, vsense) - ihold = self._calc_current_bits(min(hold_current, run_current), - vsense) - if irun < 16 and ihold < 16: - vsense = True - irun = self._calc_current_bits(run_current, vsense) - ihold = self._calc_current_bits(min(hold_current, run_current), - vsense) - return vsense, irun, ihold - def _calc_current_from_field(self, field_name): - bits = self.fields.get_field(field_name) + def _calc_current_from_bits(self, cs, vsense): sense_resistor = self.sense_resistor + 0.020 vref = 0.32 - if self.fields.get_field("vsense"): + if vsense: vref = 0.18 - return (bits + 1) * vref / (32 * sense_resistor * math.sqrt(2.)) + return (cs + 1) * vref / (32. * sense_resistor * math.sqrt(2.)) + def _calc_current(self, run_current, hold_current): + vsense = True + irun = self._calc_current_bits(run_current, True) + if irun == 31: + cur = self._calc_current_from_bits(irun, True) + if cur < run_current: + irun2 = self._calc_current_bits(run_current, False) + cur2 = self._calc_current_from_bits(irun2, False) + if abs(run_current - cur2) < abs(run_current - cur): + vsense = False + irun = irun2 + ihold = self._calc_current_bits(min(hold_current, run_current), vsense) + return vsense, irun, ihold def get_current(self): - run_current = self._calc_current_from_field("irun") - hold_current = self._calc_current_from_field("ihold") + irun = self.fields.get_field("irun") + ihold = self.fields.get_field("ihold") + vsense = self.fields.get_field("vsense") + run_current = self._calc_current_from_bits(irun, vsense) + hold_current = self._calc_current_from_bits(ihold, vsense) return run_current, hold_current, self.req_hold_current, MAX_CURRENT def set_current(self, run_current, hold_current, print_time): self.req_hold_current = hold_current diff --git a/klippy/extras/tmc2660.py b/klippy/extras/tmc2660.py index c0d8fa9b..e873c608 100644 --- a/klippy/extras/tmc2660.py +++ b/klippy/extras/tmc2660.py @@ -136,17 +136,26 @@ class TMC2660CurrentHelper: def _calc_current_bits(self, current, vsense): vref = 0.165 if vsense else 0.310 - cs = int(32 * current * self.sense_resistor * math.sqrt(2.) / vref - - 1. + .5) + sr = self.sense_resistor + cs = int(32. * sr * current * math.sqrt(2.) / vref + .5) - 1 return max(0, min(31, cs)) + def _calc_current_from_bits(self, cs, vsense): + vref = 0.165 if vsense else 0.310 + return (cs + 1) * vref / (32. * self.sense_resistor * math.sqrt(2.)) + def _calc_current(self, run_current): - vsense = False - cs = self._calc_current_bits(run_current, vsense) - if cs < 16: - vsense = True - cs = self._calc_current_bits(run_current, vsense) - return vsense, cs + vsense = True + irun = self._calc_current_bits(run_current, True) + if irun == 31: + cur = self._calc_current_from_bits(irun, True) + if cur < run_current: + irun2 = self._calc_current_bits(run_current, False) + cur2 = self._calc_current_from_bits(irun2, False) + if abs(run_current - cur2) < abs(run_current - cur): + vsense = False + irun = irun2 + return vsense, irun def _handle_printing(self, print_time): print_time -= 0.100 # Schedule slightly before deadline