class Throttle():
vref = 5
def __init__(self, io, pin, pwm):
'''exit
pwm = 0 for DAC output
pwm = 1 for PWM output
'''
self.io = io
self.pin = pin
self.pwm = pwm
self.maxV = 3.7
self.minV = 0.0
def setup(self):
if self.pwm:
self.io.setMode(self.pin)
self.io.write(self.pin, 0)
else:
self.dac = DAC(self.io)
self.dac.setup()
def setVolt(self, volt):
if volt < self.minV or volt > self.maxV:
raise ThrottleError('Volt out of bound: ', volt, ' V')
if self.pwm:
duty = self.calcDuty(volt)
self.pwmWrite(duty)
else:
self.dacWrite(volt)
def calcDuty(self, volt):
return int(volt/Throttle.vref * (2**8-1))
def off(self):
if self.pwm:
self.pwmWrite(0)
else:
self.dac.off()
def pwmWrite(self, duty, freq = 1000):
if duty == 0:
self.io.pwmStop(self.pin)
else:
self.io.pwmStart(self.pin, duty, freq)
def dacWrite(self, volt):
self.dac.setVolt(volt)