klipper/klippy/extras/ds18b20.py

# Support for 1-wire based temperature sensors
#
# Copyright (C) 2020 Alan Lord <alanslists@gmail.com>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging
import mcu

DS18_REPORT_TIME = 3.0
# Temperature can be sampled at any time but conversion time is ~750ms, so
# setting the time too low will not make the reports come faster.
DS18_MIN_REPORT_TIME = 1.0
DS18_MAX_CONSECUTIVE_ERRORS = 4

class DS18B20:
    def __init__(self, config):
        self.printer = config.get_printer()
        self.name = config.get_name().split()[-1]
        self.sensor_id = bytearray(config.get("serial_no").encode())
        self.temp = self.min_temp = self.max_temp = 0.0
        self._report_clock = 0
        self.report_time = config.getfloat(
            'ds18_report_time',
            DS18_REPORT_TIME,
            minval=DS18_MIN_REPORT_TIME
        )
        self._mcu = mcu.get_printer_mcu(self.printer, config.get('sensor_mcu'))
        self.oid = self._mcu.create_oid()
        self._mcu.register_response(self._handle_ds18b20_response,
            "ds18b20_result", self.oid)
        self._mcu.register_config_callback(self._build_config)

    def _build_config(self):
        sid = "".join(["%02x" % (x,) for x in self.sensor_id])
        self._mcu.add_config_cmd(
            "config_ds18b20 oid=%d serial=%s max_error_count=%d"
            % (self.oid, sid, DS18_MAX_CONSECUTIVE_ERRORS))

        clock = self._mcu.get_query_slot(self.oid)
        self._report_clock = self._mcu.seconds_to_clock(self.report_time)
        self._mcu.add_config_cmd("query_ds18b20 oid=%d clock=%u rest_ticks=%u"
            " min_value=%d max_value=%d" % (
                self.oid, clock, self._report_clock,
                self.min_temp * 1000, self.max_temp * 1000), is_init=True)

    def _handle_ds18b20_response(self, params):
        temp = params['value'] / 1000.0

        if params["fault"]:
            logging.info("ds18b20 reports fault %d (temp=%0.1f)",
                         params["fault"], temp)
            return

        next_clock      = self._mcu.clock32_to_clock64(params['next_clock'])
        last_read_clock = next_clock - self._report_clock
        last_read_time  = self._mcu.clock_to_print_time(last_read_clock)
        self._callback(last_read_time, temp)

    def setup_minmax(self, min_temp, max_temp):
        self.min_temp = min_temp
        self.max_temp = max_temp

    def fault(self, msg):
        self.printer.invoke_async_shutdown(msg)

    def get_report_time_delta(self):
        return self.report_time

    def setup_callback(self, cb):
        self._callback = cb

    def get_status(self, eventtime):
        return {
            'temperature': round(self.temp, 2),
        }

def load_config(config):
    # Register sensor
    pheaters = config.get_printer().load_object(config, "heaters")
    pheaters.add_sensor_factory("DS18B20", DS18B20)