adccmds: Add support for min/max temperature check filtering

Extend the ADC out of range check so that it is possible to sample
multiple times before going into a shutdown state.  This reduces the
chance that measurement noise will cause an error.  In an actual over
temperature (or under temperature event) it is expected that the
sensor will consistently report the problem, so extra checks for an
additional second or two should not substantially increase risk.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/adc_temperature.py

@@ -8,6 +8,7 @@ import logging, bisect
 SAMPLE_TIME = 0.001
 SAMPLE_COUNT = 8
 REPORT_TIME = 0.300
+RANGE_CHECK_COUNT = 4
 
 # Linear style conversion chips calibrated with two temp measurements
 class Linear:
@@ -50,7 +51,8 @@ class Linear:
     def setup_minmax(self, min_temp, max_temp):
         adc_range = [self.calc_adc(min_temp), self.calc_adc(max_temp)]
         self.mcu_adc.setup_minmax(SAMPLE_TIME, SAMPLE_COUNT,
-                                  minval=min(adc_range), maxval=max(adc_range))
+                                  minval=min(adc_range), maxval=max(adc_range),
+                                  range_check_count=RANGE_CHECK_COUNT)
     def setup_callback(self, temperature_callback):
         self.temperature_callback = temperature_callback
     def get_report_time_delta(self):

klippy/extras/thermistor.py

@@ -9,6 +9,7 @@ KELVIN_TO_CELCIUS = -273.15
 SAMPLE_TIME = 0.001
 SAMPLE_COUNT = 8
 REPORT_TIME = 0.300
+RANGE_CHECK_COUNT = 4
 
 # Analog voltage to temperature converter for thermistors
 class Thermistor:
@@ -59,7 +60,8 @@ class Thermistor:
     def setup_minmax(self, min_temp, max_temp):
         adc_range = [self.calc_adc(min_temp), self.calc_adc(max_temp)]
         self.mcu_adc.setup_minmax(SAMPLE_TIME, SAMPLE_COUNT,
-                                  minval=min(adc_range), maxval=max(adc_range))
+                                  minval=min(adc_range), maxval=max(adc_range),
+                                  range_check_count=RANGE_CHECK_COUNT)
     def setup_callback(self, temperature_callback):
         self.temperature_callback = temperature_callback
     def get_report_time_delta(self):

klippy/mcu.py

@@ -350,17 +350,19 @@ class MCU_adc:
         self._pin = pin_params['pin']
         self._min_sample = self._max_sample = 0.
         self._sample_time = self._report_time = 0.
-        self._sample_count = 0
+        self._sample_count = self._range_check_count = 0
         self._report_clock = 0
         self._oid = self._callback = None
         self._inv_max_adc = 0.
     def get_mcu(self):
         return self._mcu
-    def setup_minmax(self, sample_time, sample_count, minval=0., maxval=1.):
+    def setup_minmax(self, sample_time, sample_count,
+                     minval=0., maxval=1., range_check_count=0):
         self._sample_time = sample_time
         self._sample_count = sample_count
         self._min_sample = minval
         self._max_sample = maxval
+        self._range_check_count = range_check_count
     def setup_adc_callback(self, report_time, callback):
         self._report_time = report_time
         self._callback = callback
@@ -381,9 +383,10 @@ class MCU_adc:
             math.ceil(self._max_sample * max_adc))))
         self._mcu.add_config_cmd(
             "query_analog_in oid=%d clock=%d sample_ticks=%d sample_count=%d"
-            " rest_ticks=%d min_value=%d max_value=%d" % (
+            " rest_ticks=%d min_value=%d max_value=%d range_check_count=%d" % (
                 self._oid, clock, sample_ticks, self._sample_count,
-                self._report_clock, min_sample, max_sample), is_init=True)
+                self._report_clock, min_sample, max_sample,
+                self._range_check_count), is_init=True)
         self._mcu.register_msg(self._handle_analog_in_state, "analog_in_state"
                                , self._oid)
     def _handle_analog_in_state(self, params):

src/adccmds.c

@@ -15,6 +15,7 @@ struct analog_in {
     uint32_t rest_time, sample_time, next_begin_time;
     uint16_t value, min_value, max_value;
     struct gpio_adc pin;
+    uint8_t invalid_count, range_check_count;
     uint8_t state, sample_count;
 };
 
@@ -42,8 +43,15 @@ analog_in_event(struct timer *timer)
         a->timer.waketime += a->sample_time;
         return SF_RESCHEDULE;
     }
-    if (a->value < a->min_value || a->value > a->max_value)
+    if (likely(a->value >= a->min_value && a->value <= a->max_value)) {
+        a->invalid_count = 0;
+    } else {
+        a->invalid_count++;
+        if (a->invalid_count >= a->range_check_count) {
             try_shutdown("ADC out of range");
+            a->invalid_count = 0;
+        }
+    }
     sched_wake_task(&analog_wake);
     a->next_begin_time += a->rest_time;
     a->timer.waketime = a->next_begin_time;
@@ -75,13 +83,14 @@ command_query_analog_in(uint32_t *args)
     a->rest_time = args[4];
     a->min_value = args[5];
     a->max_value = args[6];
+    a->range_check_count = args[7];
     if (! a->sample_count)
         return;
     sched_add_timer(&a->timer);
 }
 DECL_COMMAND(command_query_analog_in,
              "query_analog_in oid=%c clock=%u sample_ticks=%u sample_count=%c"
-             " rest_ticks=%u min_value=%hu max_value=%hu");
+             " rest_ticks=%u min_value=%hu max_value=%hu range_check_count=%c");
 
 void
 analog_in_task(void)