bulk_sensor: New file with helper code for reading bulk sensors

Move the ClockSyncRegression class from adxl345.py to a new
bulk_sensors.py file.

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

1 files changed, 6 insertions, 51 deletions

diff --git a/klippy/extras/adxl345.py b/klippy/extras/adxl345.py
index 52698cb6..36dc8071 100644
--- a/klippy/extras/adxl345.py
+++ b/klippy/extras/adxl345.py
@@ -4,7 +4,7 @@
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 import logging, time, collections, threading, multiprocessing, os
-from . import bus, motion_report
+from . import bus, motion_report, bulk_sensor
 
 # ADXL345 registers
 REG_DEVID = 0x00
@@ -173,59 +173,13 @@ class AccelCommandHelper:
         val = gcmd.get("VAL", minval=0, maxval=255, parser=lambda x: int(x, 0))
         self.chip.set_reg(reg, val)
 
-# Helper class for chip clock synchronization via linear regression
-class ClockSyncRegression:
-    def __init__(self, mcu, chip_clock_smooth, decay = 1. / 20.):
-        self.mcu = mcu
-        self.chip_clock_smooth = chip_clock_smooth
-        self.decay = decay
-        self.last_chip_clock = self.last_exp_mcu_clock = 0.
-        self.mcu_clock_avg = self.mcu_clock_variance = 0.
-        self.chip_clock_avg = self.chip_clock_covariance = 0.
-    def reset(self, mcu_clock, chip_clock):
-        self.mcu_clock_avg = self.last_mcu_clock = mcu_clock
-        self.chip_clock_avg = chip_clock
-        self.mcu_clock_variance = self.chip_clock_covariance = 0.
-        self.last_chip_clock = self.last_exp_mcu_clock = 0.
-    def update(self, mcu_clock, chip_clock):
-        # Update linear regression
-        decay = self.decay
-        diff_mcu_clock = mcu_clock - self.mcu_clock_avg
-        self.mcu_clock_avg += decay * diff_mcu_clock
-        self.mcu_clock_variance = (1. - decay) * (
-            self.mcu_clock_variance + diff_mcu_clock**2 * decay)
-        diff_chip_clock = chip_clock - self.chip_clock_avg
-        self.chip_clock_avg += decay * diff_chip_clock
-        self.chip_clock_covariance = (1. - decay) * (
-            self.chip_clock_covariance + diff_mcu_clock*diff_chip_clock*decay)
-    def set_last_chip_clock(self, chip_clock):
-        base_mcu, base_chip, inv_cfreq = self.get_clock_translation()
-        self.last_chip_clock = chip_clock
-        self.last_exp_mcu_clock = base_mcu + (chip_clock-base_chip) * inv_cfreq
-    def get_clock_translation(self):
-        inv_chip_freq = self.mcu_clock_variance / self.chip_clock_covariance
-        if not self.last_chip_clock:
-            return self.mcu_clock_avg, self.chip_clock_avg, inv_chip_freq
-        # Find mcu clock associated with future chip_clock
-        s_chip_clock = self.last_chip_clock + self.chip_clock_smooth
-        scdiff = s_chip_clock - self.chip_clock_avg
-        s_mcu_clock = self.mcu_clock_avg + scdiff * inv_chip_freq
-        # Calculate frequency to converge at future point
-        mdiff = s_mcu_clock - self.last_exp_mcu_clock
-        s_inv_chip_freq = mdiff / self.chip_clock_smooth
-        return self.last_exp_mcu_clock, self.last_chip_clock, s_inv_chip_freq
-    def get_time_translation(self):
-        base_mcu, base_chip, inv_cfreq = self.get_clock_translation()
-        clock_to_print_time = self.mcu.clock_to_print_time
-        base_time = clock_to_print_time(base_mcu)
-        inv_freq = clock_to_print_time(base_mcu + inv_cfreq) - base_time
-        return base_time, base_chip, inv_freq
-
 MIN_MSG_TIME = 0.100
 
 BYTES_PER_SAMPLE = 5
 SAMPLES_PER_BLOCK = 10
 
+API_UPDATES = 0.100
+
 # Printer class that controls ADXL345 chip
 class ADXL345:
     def __init__(self, config):
@@ -259,10 +213,11 @@ class ADXL345:
         # Clock tracking
         self.last_sequence = self.max_query_duration = 0
         self.last_limit_count = self.last_error_count = 0
-        self.clock_sync = ClockSyncRegression(self.mcu, 640)
+        chip_smooth = self.data_rate * API_UPDATES * 2
+        self.clock_sync = bulk_sensor.ClockSyncRegression(mcu, chip_smooth)
         # API server endpoints
         self.api_dump = motion_report.APIDumpHelper(
-            self.printer, self._api_update, self._api_startstop, 0.100)
+            self.printer, self._api_update, self._api_startstop, API_UPDATES)
         self.name = config.get_name().split()[-1]
         wh = self.printer.lookup_object('webhooks')
         wh.register_mux_endpoint("adxl345/dump_adxl345", "sensor", self.name,