CircuitPython/MicroPythonに温度センサーTMP102(i2c)を接続する: xshige's beta notes

2020年3月24日 (火)

CircuitPython/MicroPythonに温度センサーTMP102(i2c)を接続する

2020/2/24

CircuitPython TMP102(i2c)

概要

CircuitPython/MicroPythonに以下の温度センサーTMP102(i2c)を接続する。
(ホストPCとしてはubuntuを想定している)

TMP102搭載デジタル温度センサモジュール

接続

以下のように接続する。

Wiring:

TMP102	Teensy4.0(CircuitPython)
SCL	D19(SCL0)
SDA	D18(SDA0)
VCC	3.3V
GND	GND

該当モジュールのインストール

Module Install:


  git clone https://github.com/khoulihan/micropython-tmp102.git
  cd micropython-tmp102

  cp _tmp102.py tmp102_cpy.py

  # Patch　
  次項目の内容のようにtmp102_cpy.pyにパッチする。

  # copy related modules
  cp tmp102_cpy.py CIRCUTPY/lib/

tmp102_cpy.pyの内容:
「#m」を含む行が修正行になる。
(コメントアウト行も含む)


  # tmp102_cpy.py
  # 2020/3/24 modification for CircutPython

  REGISTER_TEMP = 0
  REGISTER_CONFIG = 1

  EXTENDED_MODE_BIT = 0x10

  def _set_bit(b, mask):
      return b | mask

  def _clear_bit(b, mask):
      return b & ~mask

  def _set_bit_for_boolean(b, mask, val):
      if val:
          return _set_bit(b, mask)
      else:
          return _clear_bit(b, mask)


  class Tmp102(object):

      def __init__(self, bus, address, temperature_convertor=None, **kwargs):
          # There doesn't seem to be a way to check this at present. The first
          # send or recv should throw an error instead if the mode is incorrect.
          #if not bus.in_master_mode():
          #    raise ValueError('bus must be in master mode')
          self.bus = bus
          self.address = address
          self.temperature_convertor = temperature_convertor
          # The register defaults to the temperature.
          self._last_write_register = REGISTER_TEMP
          self._extended_mode = False
          if len(kwargs) > 0:
              # Apply the passed in settings
              config = bytearray(self._get_config())
              for key, value in kwargs.items():
                  applyfunc = '_apply_{}'.format(key)
                  config = getattr(self, applyfunc)(config, value)
              self._set_config(config)

              if 'thermostat_high_temperature' in kwargs:
                  self.thermostat_high_temperature = kwargs['thermostat_high_temperature']
              if 'thermostat_low_temperature' in kwargs:
                  self.thermostat_low_temperature = kwargs['thermostat_low_temperature']

      def _read_register(self, register):
          val = bytearray(2) #m
          if register != self._last_write_register:
              # Reads come from the last register written.
              self._write_register(register)
          try:
              #m val = self.bus.readfrom(self.address, 2)
              self.bus.readfrom_into(self.address, val)           
          except AttributeError:
              #m val = self.bus.recv(2, addr=self.address)
              self.bus.readfrom_into(self.address, val) 
          return val

      def _write_register(self, register, value=None):
          bvals = bytearray()
          bvals.append(register)
          if value is not None:
              for val in value:
                  bvals.append(val)
          try:
              self.bus.writeto(self.address, bvals)
          except AttributeError:
              self.bus.send(bvals, addr=self.address)
          self._last_write_register = register

      def _get_config(self):
          return self._read_register(REGISTER_CONFIG)

      def _set_config(self, config):
          self._write_register(REGISTER_CONFIG, config)
          self._extended_mode = config[1] & EXTENDED_MODE_BIT

      def _read_temperature_register(self, register):
          rt = self._read_register(register)
          lo = rt[1]
          hi = rt[0]
          negative = (hi >> 7) == 1
          shift = 4
          if self._extended_mode:
              shift = 3
          if not negative:
              t = (((hi * 256) + lo) >> shift) * 0.0625
          else:
              remove_bit = 0b011111111111
              if self._extended_mode:
                  remove_bit = 0b0111111111111
              ti = (((hi * 256) + lo) >> shift)
              # Complement, but remove the first bit.
              ti = ~ti & remove_bit
              t = -(ti * 0.0625)
          if self.temperature_convertor is not None:
              t = self.temperature_convertor.convert_to(t)
          return rt, t

      @property
      def temperature(self):
          """
          The most recently recorded temperature.
          """
          rt, t = self._read_temperature_register(REGISTER_TEMP)
          return t

CircuitPythonとMicroPythonに共通してあるi2c.writeto,i2c.readfrom_intoを使用しているので、両方に対応できている。

Demo Script(動作確認)


  import time
  import busio
  import board
  i2c = busio.I2C(board.SCL, board.SDA)
  i2c.try_lock()

  from tmp102_cpy import Tmp102
  sensor = Tmp102(i2c, 0x48)

  while True:
    print('Temperature: {0:.1f}'.format(sensor.temperature))
    time.sleep(2)

MicroPython(Nucleo)の場合

該当モジュールtmp102_cpy.pyが、CircuitPython/MicroPython両方に対応しているのでそのまま/flashに書き込むだけでパッチなどは必要ない。

Demo Script:


  import time
  from machine import Pin, I2C
  i2c = I2C(1)

  from tmp102_cpy import Tmp102
  sensor = Tmp102(i2c, 0x48)

  while True:
    print('Temperature: {0:.1f}'.format(sensor.temperature))
    time.sleep(2)