109 lines
3.6 KiB
Python
109 lines
3.6 KiB
Python
# Support for I2C based LM75/LM75A temperature sensors
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#
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# Copyright (C) 2020 Boleslaw Ciesielski <combolek@users.noreply.github.com>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import logging
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from . import bus
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LM75_CHIP_ADDR = 0x48
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LM75_I2C_SPEED = 100000
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LM75_REGS = {
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'TEMP' : 0x00,
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'CONF' : 0x01,
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'THYST' : 0x02,
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'TOS' : 0x03,
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'PRODID' : 0x07 # TI LM75A chips only?
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}
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LM75_REPORT_TIME = .8
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# Temperature can be sampled at any time but the read aborts
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# the current conversion. Conversion time is 300ms so make
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# sure not to read too often.
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LM75_MIN_REPORT_TIME = .5
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class LM75:
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def __init__(self, config):
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self.printer = config.get_printer()
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self.name = config.get_name().split()[-1]
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self.reactor = self.printer.get_reactor()
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self.i2c = bus.MCU_I2C_from_config(config, LM75_CHIP_ADDR,
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LM75_I2C_SPEED)
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self.mcu = self.i2c.get_mcu()
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self.report_time = config.getfloat('lm75_report_time', LM75_REPORT_TIME,
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minval=LM75_MIN_REPORT_TIME)
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self.temp = self.min_temp = self.max_temp = 0.0
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self.sample_timer = self.reactor.register_timer(self._sample_lm75)
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self.printer.add_object("lm75 " + self.name, self)
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self.printer.register_event_handler("klippy:connect",
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self.handle_connect)
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def handle_connect(self):
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self._init_lm75()
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self.reactor.update_timer(self.sample_timer, self.reactor.NOW)
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def setup_minmax(self, min_temp, max_temp):
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self.min_temp = min_temp
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self.max_temp = max_temp
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def setup_callback(self, cb):
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self._callback = cb
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def get_report_time_delta(self):
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return self.report_time
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def degrees_from_sample(self, x):
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# The temp sample is encoded in the top 9 bits of a 16-bit
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# value. Resolution is 0.5 degrees C.
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return x[0] + (x[1] >> 7) * 0.5
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def _init_lm75(self):
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# Check and report the chip ID but ignore errors since many
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# chips don't have it
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try:
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prodid = self.read_register('PRODID', 1)[0]
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logging.info("lm75: Chip ID %#x" % prodid)
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except:
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pass
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def _sample_lm75(self, eventtime):
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try:
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sample = self.read_register('TEMP', 2)
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self.temp = self.degrees_from_sample(sample)
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except Exception:
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logging.exception("lm75: Error reading data")
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self.temp = 0.0
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return self.reactor.NEVER
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if self.temp < self.min_temp or self.temp > self.max_temp:
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self.printer.invoke_shutdown(
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"LM75 temperature %0.1f outside range of %0.1f:%.01f"
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% (self.temp, self.min_temp, self.max_temp))
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measured_time = self.reactor.monotonic()
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self._callback(self.mcu.estimated_print_time(measured_time), self.temp)
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return measured_time + self.report_time
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def read_register(self, reg_name, read_len):
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# read a single register
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regs = [LM75_REGS[reg_name]]
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params = self.i2c.i2c_read(regs, read_len)
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return bytearray(params['response'])
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def write_register(self, reg_name, data):
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if type(data) is not list:
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data = [data]
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reg = LM75_REGS[reg_name]
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data.insert(0, reg)
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self.i2c.i2c_write(data)
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def get_status(self, eventtime):
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return {
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'temperature': self.temp,
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}
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def load_config(config):
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# Register sensor
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pheaters = config.get_printer().load_object(config, "heaters")
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pheaters.add_sensor_factory("LM75", LM75)
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