drivers/onewire: Move onewire.py, ds18x20.py from esp8266 to drivers.
These drivers can now be used by any port (so long as that port has the _onewire driver from extmod/modonewire.c). These drivers replace the existing 1-wire and DS18X20 drivers in the drivers/onewire directory. The existing ones were pyboard-specific and not very efficient nor minimal (although the 1-wire driver was written in pure Python it only worked at large enough CPU frequency). This commit brings backwards incompatible API changes to the existing 1-wire drivers. User code should be converted to use the new drivers, or check out the old version of the code and keep a local copy (it should continue to work unchanged).
This commit is contained in:
Damien George
parent
b19138e82e
commit
a065d78675
@ -1,101 +1,51 @@
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"""
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DS18x20 temperature sensor driver for MicroPython.
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# DS18x20 temperature sensor driver for MicroPython.
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# MIT license; Copyright (c) 2016 Damien P. George
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This driver uses the OneWire driver to control DS18S20 and DS18B20
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temperature sensors. It supports multiple devices on the same 1-wire bus.
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from micropython import const
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The following example assumes the ground of your DS18x20 is connected to
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Y11, vcc is connected to Y9 and the data pin is connected to Y10.
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_CONVERT = const(0x44)
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_RD_SCRATCH = const(0xbe)
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_WR_SCRATCH = const(0x4e)
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>>> from machine import Pin
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>>> gnd = Pin('Y11', Pin.OUT_PP)
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>>> gnd.off()
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>>> vcc = Pin('Y9', Pin.OUT_PP)
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>>> vcc.on()
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class DS18X20:
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def __init__(self, onewire):
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self.ow = onewire
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self.buf = bytearray(9)
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>>> from ds18x20 import DS18X20
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>>> d = DS18X20(Pin('Y10'))
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def scan(self):
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return [rom for rom in self.ow.scan() if rom[0] == 0x10 or rom[0] == 0x28]
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Call read_temps to read all sensors:
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def convert_temp(self):
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self.ow.reset(True)
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self.ow.writebyte(self.ow.SKIP_ROM)
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self.ow.writebyte(_CONVERT)
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>>> result = d.read_temps()
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>>> print(result)
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[20.875, 20.8125]
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def read_scratch(self, rom):
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self.ow.reset(True)
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self.ow.select_rom(rom)
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self.ow.writebyte(_RD_SCRATCH)
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self.ow.readinto(self.buf)
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if self.ow.crc8(self.buf):
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raise Exception('CRC error')
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return self.buf
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Call read_temp to read the temperature of a specific sensor:
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def write_scratch(self, rom, buf):
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self.ow.reset(True)
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self.ow.select_rom(rom)
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self.ow.writebyte(_WR_SCRATCH)
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self.ow.write(buf)
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>>> result = d.read_temp(d.roms[0])
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>>> print(result)
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20.25
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If only one DS18x20 is attached to the bus, then you don't need to
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pass a ROM to read_temp:
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>>> result = d.read_temp()
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>>> print(result)
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20.25
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"""
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from onewire import OneWire
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class DS18X20(object):
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def __init__(self, pin):
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self.ow = OneWire(pin)
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# Scan the 1-wire devices, but only keep those which have the
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# correct # first byte in their rom for a DS18x20 device.
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self.roms = [rom for rom in self.ow.scan() if rom[0] == 0x10 or rom[0] == 0x28]
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def read_temp(self, rom=None):
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"""
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Read and return the temperature of one DS18x20 device.
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Pass the 8-byte bytes object with the ROM of the specific device you want to read.
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If only one DS18x20 device is attached to the bus you may omit the rom parameter.
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"""
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rom = rom or self.roms[0]
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ow = self.ow
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ow.reset()
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ow.select_rom(rom)
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ow.write_byte(0x44) # Convert Temp
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while True:
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if ow.read_bit():
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break
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ow.reset()
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ow.select_rom(rom)
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ow.write_byte(0xbe) # Read scratch
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data = ow.read_bytes(9)
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return self.convert_temp(rom[0], data)
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def read_temps(self):
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"""
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Read and return the temperatures of all attached DS18x20 devices.
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"""
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temps = []
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for rom in self.roms:
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temps.append(self.read_temp(rom))
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return temps
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def convert_temp(self, rom0, data):
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"""
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Convert the raw temperature data into degrees celsius and return as a float.
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"""
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temp_lsb = data[0]
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temp_msb = data[1]
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if rom0 == 0x10:
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if temp_msb != 0:
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# convert negative number
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temp_read = temp_lsb >> 1 | 0x80 # truncate bit 0 by shifting, fill high bit with 1.
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temp_read = -((~temp_read + 1) & 0xff) # now convert from two's complement
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def read_temp(self, rom):
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buf = self.read_scratch(rom)
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if rom[0] == 0x10:
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if buf[1]:
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t = buf[0] >> 1 | 0x80
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t = -((~t + 1) & 0xff)
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else:
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temp_read = temp_lsb >> 1 # truncate bit 0 by shifting
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count_remain = data[6]
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count_per_c = data[7]
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temp = temp_read - 0.25 + (count_per_c - count_remain) / count_per_c
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return temp
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elif rom0 == 0x28:
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temp = (temp_msb << 8 | temp_lsb) / 16
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if (temp_msb & 0xf8) == 0xf8: # for negative temperature
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temp -= 0x1000
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return temp
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t = buf[0] >> 1
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return t - 0.25 + (buf[7] - buf[6]) / buf[7]
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else:
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assert False
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t = buf[1] << 8 | buf[0]
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if t & 0x8000: # sign bit set
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t = -((t ^ 0xffff) + 1)
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return t / 16
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@ -1,336 +1,91 @@
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"""
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OneWire library ported to MicroPython by Jason Hildebrand.
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# 1-Wire driver for MicroPython
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# MIT license; Copyright (c) 2016 Damien P. George
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from micropython import const
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import _onewire as _ow
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TODO:
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* implement and test parasite-power mode (as an init option)
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* port the crc checks
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The original upstream copyright and terms follow.
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------------------------------------------------------------------------------
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Copyright (c) 2007, Jim Studt (original old version - many contributors since)
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OneWire has been maintained by Paul Stoffregen (paul@pjrc.com) since
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January 2010.
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26 Sept 2008 -- Robin James
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Jim Studt's original library was modified by Josh Larios.
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Tom Pollard, pollard@alum.mit.edu, contributed around May 20, 2008
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Much of the code was inspired by Derek Yerger's code, though I don't
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think much of that remains. In any event that was..
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(copyleft) 2006 by Derek Yerger - Free to distribute freely.
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"""
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import pyb
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from pyb import disable_irq
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from pyb import enable_irq
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class OneWireError(Exception):
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pass
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class OneWire:
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SEARCH_ROM = const(0xf0)
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MATCH_ROM = const(0x55)
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SKIP_ROM = const(0xcc)
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def __init__(self, pin):
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"""
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Pass the data pin connected to your one-wire device(s), for example Pin('X1').
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The one-wire protocol allows for multiple devices to be attached.
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"""
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self.data_pin = pin
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self.write_delays = (1, 40, 40, 1)
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self.read_delays = (1, 1, 40)
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self.pin = pin
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self.pin.init(pin.OPEN_DRAIN)
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# cache a bunch of methods and attributes. This is necessary in _write_bit and
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# _read_bit to achieve the timing required by the OneWire protocol.
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self.cache = (pin.init, pin.value, pin.OUT_PP, pin.IN, pin.PULL_UP)
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def reset(self, required=False):
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reset = _ow.reset(self.pin)
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if required and not reset:
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raise OneWireError
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return reset
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pin.init(pin.IN, pin.PULL_UP)
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def readbit(self):
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return _ow.readbit(self.pin)
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def reset(self):
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"""
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Perform the onewire reset function.
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Returns 1 if a device asserted a presence pulse, 0 otherwise.
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def readbyte(self):
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return _ow.readbyte(self.pin)
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If you receive 0, then check your wiring and make sure you are providing
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power and ground to your devices.
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"""
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retries = 25
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self.data_pin.init(self.data_pin.IN, self.data_pin.PULL_UP)
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def readinto(self, buf):
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for i in range(len(buf)):
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buf[i] = _ow.readbyte(self.pin)
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# We will wait up to 250uS for
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# the bus to come high, if it doesn't then it is broken or shorted
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# and we return a 0;
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def writebit(self, value):
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return _ow.writebit(self.pin, value)
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# wait until the wire is high... just in case
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while True:
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if self.data_pin.value():
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break
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retries -= 1
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if retries == 0:
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raise OSError("OneWire pin didn't go high")
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pyb.udelay(10)
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def writebyte(self, value):
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return _ow.writebyte(self.pin, value)
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# pull the bus low for at least 480us
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self.data_pin.low()
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self.data_pin.init(self.data_pin.OUT_PP)
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pyb.udelay(480)
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# If there is a slave present, it should pull the bus low within 60us
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i = pyb.disable_irq()
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self.data_pin.init(self.data_pin.IN, self.data_pin.PULL_UP)
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pyb.udelay(70)
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presence = not self.data_pin.value()
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pyb.enable_irq(i)
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pyb.udelay(410)
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return presence
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def write_bit(self, value):
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"""
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Write a single bit.
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"""
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pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP = self.cache
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self._write_bit(value, pin_init, pin_value, Pin_OUT_PP)
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def _write_bit(self, value, pin_init, pin_value, Pin_OUT_PP):
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"""
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Write a single bit - requires cached methods/attributes be passed as arguments.
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See also write_bit()
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"""
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d0, d1, d2, d3 = self.write_delays
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udelay = pyb.udelay
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if value:
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# write 1
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i = disable_irq()
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pin_value(0)
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pin_init(Pin_OUT_PP)
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udelay(d0)
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pin_value(1)
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enable_irq(i)
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udelay(d1)
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else:
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# write 0
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i = disable_irq()
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pin_value(0)
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pin_init(Pin_OUT_PP)
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udelay(d2)
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pin_value(1)
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enable_irq(i)
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udelay(d3)
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def write_byte(self, value):
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"""
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Write a byte. The pin will go tri-state at the end of the write to avoid
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heating in a short or other mishap.
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"""
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pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP = self.cache
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for i in range(8):
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self._write_bit(value & 1, pin_init, pin_value, Pin_OUT_PP)
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value >>= 1
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pin_init(Pin_IN, Pin_PULL_UP)
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def write_bytes(self, bytestring):
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"""
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Write a sequence of bytes.
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"""
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for byte in bytestring:
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self.write_byte(byte)
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def _read_bit(self, pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP):
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"""
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Read a single bit - requires cached methods/attributes be passed as arguments.
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See also read_bit()
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"""
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d0, d1, d2 = self.read_delays
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udelay = pyb.udelay
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pin_init(Pin_IN, Pin_PULL_UP) # TODO why do we need this?
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i = disable_irq()
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pin_value(0)
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pin_init(Pin_OUT_PP)
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udelay(d0)
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pin_init(Pin_IN, Pin_PULL_UP)
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udelay(d1)
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value = pin_value()
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enable_irq(i)
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udelay(d2)
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return value
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def read_bit(self):
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"""
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Read a single bit.
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"""
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pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP = self.cache
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return self._read_bit(pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP)
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def read_byte(self):
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"""
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Read a single byte and return the value as an integer.
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See also read_bytes()
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"""
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pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP = self.cache
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value = 0
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for i in range(8):
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bit = self._read_bit(pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP)
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value |= bit << i
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return value
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def read_bytes(self, count):
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"""
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Read a sequence of N bytes.
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The bytes are returned as a bytearray.
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"""
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s = bytearray(count)
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for i in range(count):
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s[i] = self.read_byte()
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return s
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def write(self, buf):
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for b in buf:
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_ow.writebyte(self.pin, b)
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def select_rom(self, rom):
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"""
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Select a specific device to talk to. Pass in rom as a bytearray (8 bytes).
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"""
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assert len(rom) == 8, "ROM must be 8 bytes"
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self.reset()
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self.write_byte(0x55) # ROM MATCH
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self.write_bytes(rom)
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def read_rom(self):
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"""
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Read the ROM - this works if there is only a single device attached.
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"""
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self.reset()
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self.write_byte(0x33) # READ ROM
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rom = self.read_bytes(8)
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# TODO: check CRC of the ROM
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return rom
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def skip_rom(self):
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"""
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Send skip-rom command - this works if there is only one device attached.
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"""
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self.write_byte(0xCC) # SKIP ROM
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def depower(self):
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self.data_pin.init(self.data_pin.IN, self.data_pin.PULL_NONE)
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self.writebyte(MATCH_ROM)
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self.write(rom)
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def scan(self):
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"""
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Return a list of ROMs for all attached devices.
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Each ROM is returned as a bytes object of 8 bytes.
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"""
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devices = []
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self._reset_search()
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while True:
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rom = self._search()
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if not rom:
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return devices
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devices.append(rom)
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def _reset_search(self):
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self.last_discrepancy = 0
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self.last_device_flag = False
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self.last_family_discrepancy = 0
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self.rom = bytearray(8)
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def _search(self):
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# initialize for search
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id_bit_number = 1
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last_zero = 0
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rom_byte_number = 0
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rom_byte_mask = 1
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search_result = 0
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pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP = self.cache
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# if the last call was not the last one
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if not self.last_device_flag:
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# 1-Wire reset
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if not self.reset():
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self._reset_search()
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return None
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# issue the search command
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self.write_byte(0xF0)
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# loop to do the search
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while rom_byte_number < 8: # loop until through all ROM bytes 0-7
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# read a bit and its complement
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id_bit = self._read_bit(pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP)
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cmp_id_bit = self._read_bit(pin_init, pin_value, Pin_OUT_PP, Pin_IN, Pin_PULL_UP)
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# check for no devices on 1-wire
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if (id_bit == 1) and (cmp_id_bit == 1):
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diff = 65
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rom = False
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for i in range(0xff):
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rom, diff = self._search_rom(rom, diff)
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if rom:
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devices += [rom]
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if diff == 0:
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break
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return devices
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def _search_rom(self, l_rom, diff):
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if not self.reset():
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return None, 0
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self.writebyte(SEARCH_ROM)
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if not l_rom:
|
||||
l_rom = bytearray(8)
|
||||
rom = bytearray(8)
|
||||
next_diff = 0
|
||||
i = 64
|
||||
for byte in range(8):
|
||||
r_b = 0
|
||||
for bit in range(8):
|
||||
b = self.readbit()
|
||||
if self.readbit():
|
||||
if b: # there are no devices or there is an error on the bus
|
||||
return None, 0
|
||||
else:
|
||||
# all devices coupled have 0 or 1
|
||||
if (id_bit != cmp_id_bit):
|
||||
search_direction = id_bit # bit write value for search
|
||||
else:
|
||||
# if this discrepancy if before the Last Discrepancy
|
||||
# on a previous next then pick the same as last time
|
||||
if (id_bit_number < self.last_discrepancy):
|
||||
search_direction = (self.rom[rom_byte_number] & rom_byte_mask) > 0
|
||||
else:
|
||||
# if equal to last pick 1, if not then pick 0
|
||||
search_direction = (id_bit_number == self.last_discrepancy)
|
||||
if not b: # collision, two devices with different bit meaning
|
||||
if diff > i or ((l_rom[byte] & (1 << bit)) and diff != i):
|
||||
b = 1
|
||||
next_diff = i
|
||||
self.writebit(b)
|
||||
if b:
|
||||
r_b |= 1 << bit
|
||||
i -= 1
|
||||
rom[byte] = r_b
|
||||
return rom, next_diff
|
||||
|
||||
# if 0 was picked then record its position in LastZero
|
||||
if search_direction == 0:
|
||||
last_zero = id_bit_number
|
||||
|
||||
# check for Last discrepancy in family
|
||||
if last_zero < 9:
|
||||
self.last_family_discrepancy = last_zero
|
||||
|
||||
# set or clear the bit in the ROM byte rom_byte_number
|
||||
# with mask rom_byte_mask
|
||||
if search_direction == 1:
|
||||
self.rom[rom_byte_number] |= rom_byte_mask
|
||||
else:
|
||||
self.rom[rom_byte_number] &= ~rom_byte_mask
|
||||
|
||||
# serial number search direction write bit
|
||||
#print('sd', search_direction)
|
||||
self.write_bit(search_direction)
|
||||
|
||||
# increment the byte counter id_bit_number
|
||||
# and shift the mask rom_byte_mask
|
||||
id_bit_number += 1
|
||||
rom_byte_mask <<= 1
|
||||
|
||||
# if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
|
||||
if rom_byte_mask == 0x100:
|
||||
rom_byte_number += 1
|
||||
rom_byte_mask = 1
|
||||
|
||||
# if the search was successful then
|
||||
if not (id_bit_number < 65):
|
||||
# search successful so set last_discrepancy,last_device_flag,search_result
|
||||
self.last_discrepancy = last_zero
|
||||
|
||||
# check for last device
|
||||
if self.last_discrepancy == 0:
|
||||
self.last_device_flag = True
|
||||
search_result = True
|
||||
|
||||
# if no device found then reset counters so next 'search' will be like a first
|
||||
if not search_result or not self.rom[0]:
|
||||
self._reset_search()
|
||||
return None
|
||||
else:
|
||||
return bytes(self.rom)
|
||||
def crc8(self, data):
|
||||
return _ow.crc8(data)
|
||||
|
||||
@ -1,51 +0,0 @@
|
||||
# DS18x20 temperature sensor driver for MicroPython.
|
||||
# MIT license; Copyright (c) 2016 Damien P. George
|
||||
|
||||
from micropython import const
|
||||
|
||||
_CONVERT = const(0x44)
|
||||
_RD_SCRATCH = const(0xbe)
|
||||
_WR_SCRATCH = const(0x4e)
|
||||
|
||||
class DS18X20:
|
||||
def __init__(self, onewire):
|
||||
self.ow = onewire
|
||||
self.buf = bytearray(9)
|
||||
|
||||
def scan(self):
|
||||
return [rom for rom in self.ow.scan() if rom[0] == 0x10 or rom[0] == 0x28]
|
||||
|
||||
def convert_temp(self):
|
||||
self.ow.reset(True)
|
||||
self.ow.writebyte(self.ow.SKIP_ROM)
|
||||
self.ow.writebyte(_CONVERT)
|
||||
|
||||
def read_scratch(self, rom):
|
||||
self.ow.reset(True)
|
||||
self.ow.select_rom(rom)
|
||||
self.ow.writebyte(_RD_SCRATCH)
|
||||
self.ow.readinto(self.buf)
|
||||
if self.ow.crc8(self.buf):
|
||||
raise Exception('CRC error')
|
||||
return self.buf
|
||||
|
||||
def write_scratch(self, rom, buf):
|
||||
self.ow.reset(True)
|
||||
self.ow.select_rom(rom)
|
||||
self.ow.writebyte(_WR_SCRATCH)
|
||||
self.ow.write(buf)
|
||||
|
||||
def read_temp(self, rom):
|
||||
buf = self.read_scratch(rom)
|
||||
if rom[0] == 0x10:
|
||||
if buf[1]:
|
||||
t = buf[0] >> 1 | 0x80
|
||||
t = -((~t + 1) & 0xff)
|
||||
else:
|
||||
t = buf[0] >> 1
|
||||
return t - 0.25 + (buf[7] - buf[6]) / buf[7]
|
||||
else:
|
||||
t = buf[1] << 8 | buf[0]
|
||||
if t & 0x8000: # sign bit set
|
||||
t = -((t ^ 0xffff) + 1)
|
||||
return t / 16
|
||||
@ -1,91 +0,0 @@
|
||||
# 1-Wire driver for MicroPython on ESP8266
|
||||
# MIT license; Copyright (c) 2016 Damien P. George
|
||||
|
||||
from micropython import const
|
||||
import _onewire as _ow
|
||||
|
||||
class OneWireError(Exception):
|
||||
pass
|
||||
|
||||
class OneWire:
|
||||
SEARCH_ROM = const(0xf0)
|
||||
MATCH_ROM = const(0x55)
|
||||
SKIP_ROM = const(0xcc)
|
||||
|
||||
def __init__(self, pin):
|
||||
self.pin = pin
|
||||
self.pin.init(pin.OPEN_DRAIN)
|
||||
|
||||
def reset(self, required=False):
|
||||
reset = _ow.reset(self.pin)
|
||||
if required and not reset:
|
||||
raise OneWireError
|
||||
return reset
|
||||
|
||||
def readbit(self):
|
||||
return _ow.readbit(self.pin)
|
||||
|
||||
def readbyte(self):
|
||||
return _ow.readbyte(self.pin)
|
||||
|
||||
def readinto(self, buf):
|
||||
for i in range(len(buf)):
|
||||
buf[i] = _ow.readbyte(self.pin)
|
||||
|
||||
def writebit(self, value):
|
||||
return _ow.writebit(self.pin, value)
|
||||
|
||||
def writebyte(self, value):
|
||||
return _ow.writebyte(self.pin, value)
|
||||
|
||||
def write(self, buf):
|
||||
for b in buf:
|
||||
_ow.writebyte(self.pin, b)
|
||||
|
||||
def select_rom(self, rom):
|
||||
self.reset()
|
||||
self.writebyte(MATCH_ROM)
|
||||
self.write(rom)
|
||||
|
||||
def scan(self):
|
||||
devices = []
|
||||
diff = 65
|
||||
rom = False
|
||||
for i in range(0xff):
|
||||
rom, diff = self._search_rom(rom, diff)
|
||||
if rom:
|
||||
devices += [rom]
|
||||
if diff == 0:
|
||||
break
|
||||
return devices
|
||||
|
||||
def _search_rom(self, l_rom, diff):
|
||||
if not self.reset():
|
||||
return None, 0
|
||||
self.writebyte(SEARCH_ROM)
|
||||
if not l_rom:
|
||||
l_rom = bytearray(8)
|
||||
rom = bytearray(8)
|
||||
next_diff = 0
|
||||
i = 64
|
||||
for byte in range(8):
|
||||
r_b = 0
|
||||
for bit in range(8):
|
||||
b = self.readbit()
|
||||
if self.readbit():
|
||||
if b: # there are no devices or there is an error on the bus
|
||||
return None, 0
|
||||
else:
|
||||
if not b: # collision, two devices with different bit meaning
|
||||
if diff > i or ((l_rom[byte] & (1 << bit)) and diff != i):
|
||||
b = 1
|
||||
next_diff = i
|
||||
self.writebit(b)
|
||||
if b:
|
||||
r_b |= 1 << bit
|
||||
i -= 1
|
||||
rom[byte] = r_b
|
||||
return rom, next_diff
|
||||
|
||||
def crc8(self, data):
|
||||
return _ow.crc8(data)
|
||||
Loading…
Reference in New Issue
Block a user