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dallas.py
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dallas.py
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# (c) [email protected]
# simple ds1820 ds18b20 module
# reads only one sensor per pin
from machine import Pin
import _onewire
class ds1820:
#configure pin to onewire transmission
def init(pin):
Pin(pin, Pin.OPEN_DRAIN, Pin.PULL_UP)
#send convert command to sensor
def convert(pin):
_onewire.reset(Pin(pin))
_onewire.writebyte(Pin(pin), 0xcc) #skip rom
_onewire.writebyte(Pin(pin), 0x44) #convert
#send read temperature command to sensor
def read(pin):
_onewire.reset(Pin(pin))
_onewire.writebyte(Pin(pin), 0xcc) #skip rom
_onewire.writebyte(Pin(pin), 0xbe) #read scratchpad
tlo = _onewire.readbyte(Pin(pin))
thi = _onewire.readbyte(Pin(pin))
_onewire.reset(Pin(pin))
#convert raw values to human eye readable
temp = tlo + thi * 256
if temp > 32767:
temp = temp - 65536
temp = temp * 0.5
return(temp)
class ds18b20:
#configure pin to onewire transmission
def init(pin):
Pin(pin, Pin.OPEN_DRAIN, Pin.PULL_UP)
#send convert command to sensor
def convert(pin):
_onewire.reset(Pin(pin))
_onewire.writebyte(Pin(pin), 0xcc) #skip rom
_onewire.writebyte(Pin(pin), 0x44) #convert
#send read temperature command to sensor
def read(pin):
_onewire.reset(Pin(pin))
_onewire.writebyte(Pin(pin), 0xcc) #skip rom
_onewire.writebyte(Pin(pin), 0xbe) #read scratchpad
#read raw temperature
tlo = _onewire.readbyte(Pin(pin))
thi = _onewire.readbyte(Pin(pin))
_onewire.reset(Pin(pin))
#convert raw values to human eye readable
temp = tlo + thi * 256
if temp > 32767:
temp = temp - 65536
temp = temp * 0.0625
return(temp)