84 lines
3.0 KiB
Python
84 lines
3.0 KiB
Python
from pyA20.gpio import gpio as GPIO
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import threading
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import time
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class OrangePwm(threading.Thread):
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def __init__(self, frequency, gpioPin, gpioScheme=0):
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"""
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Init the OrangePwm instance. Expected parameters are :
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- frequency : the frequency in Hz for the PWM pattern. A correct value may be 100.
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- gpioPin : the gpio.port which will act as PWM ouput
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- gpioScheme : saved for compatibility with PiZyPWM code
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"""
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super().__init__()
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self.baseTime = 1.0 / frequency
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self.maxCycle = 100.0
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self.sliceTime = self.baseTime / self.maxCycle
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self.gpioPin = gpioPin
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self.terminated = False
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self.toTerminate = False
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# GPIO.setmode(gpioScheme)
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def start(self, dutyCycle):
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"""
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Start PWM output. Expected parameter is :
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- dutyCycle : percentage of a single pattern to set HIGH output on the GPIO pin
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Example : with a frequency of 1 Hz, and a duty cycle set to 25, GPIO pin will
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stay HIGH for 1*(25/100) seconds on HIGH output, and 1*(75/100) seconds on LOW output.
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"""
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self.dutyCycle = dutyCycle
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GPIO.setcfg(self.gpioPin, GPIO.OUTPUT)
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self.thread = threading.Thread(None, self.run, None, (), {})
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self.thread.start()
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def run(self):
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"""
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Run the PWM pattern into a background thread. This function should not be called outside of this class.
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"""
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while self.toTerminate == False:
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if self.dutyCycle > 0:
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GPIO.output(self.gpioPin, GPIO.HIGH)
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time.sleep(self.dutyCycle * self.sliceTime)
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if self.dutyCycle < self.maxCycle:
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GPIO.output(self.gpioPin, GPIO.LOW)
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time.sleep((self.maxCycle - self.dutyCycle) * self.sliceTime)
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self.terminated = True
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def changeDutyCycle(self, dutyCycle):
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"""
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Change the duration of HIGH output of the pattern. Expected parameter is :
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- dutyCycle : percentage of a single pattern to set HIGH output on the GPIO pin
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Example : with a frequency of 1 Hz, and a duty cycle set to 25, GPIO pin will
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stay HIGH for 1*(25/100) seconds on HIGH output, and 1*(75/100) seconds on LOW output.
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"""
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self.dutyCycle = dutyCycle
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def changeFrequency(self, frequency):
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"""
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Change the frequency of the PWM pattern. Expected parameter is :
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- frequency : the frequency in Hz for the PWM pattern. A correct value may be 100.
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Example : with a frequency of 1 Hz, and a duty cycle set to 25, GPIO pin will
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stay HIGH for 1*(25/100) seconds on HIGH output, and 1*(75/100) seconds on LOW output.
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"""
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self.baseTime = 1.0 / frequency
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self.sliceTime = self.baseTime / self.maxCycle
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def stop(self):
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"""
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Stops PWM output.
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"""
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self.toTerminate = True
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while self.terminated == False:
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# Just wait
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time.sleep(0.01)
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GPIO.output(self.gpioPin, GPIO.LOW)
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GPIO.setcfg(self.gpioPin, GPIO.INPUT)
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