def tone(pin, frequency, duration=None):
"""Generates a square wave of the specified frequency on pin.
Args:
- pin(PWM1 to PWM6): A PWM pin
- frequency(int): A value between 1 and 500000
- duration(int): tone's durations in second
"""
global pwm_pins
if pin not in pwm_pins:
print "Pin must be one of:"
for key in pwm_pins:
print key
exit(1)
if frequency < 1 or frequency > 500000:
print "Invalid frequency"
exit(1)
initMatch(0, 1000000/frequency)
initMatch(pwm_pins[pin], 500000/frequency)
PWM_ChannelCmd(LPC_PWM1, pwm_pins[pin], FunctionalState.ENABLE)
PWM_ResetCounter(LPC_PWM1)
PWM_CounterCmd(LPC_PWM1, FunctionalState.ENABLE)
PWM_Cmd(LPC_PWM1, FunctionalState.ENABLE)
if duration:
t = threading.Timer(float(duration)/1000.0, noTone, [pin])
t.start()
def analogWrite(pin, value):
"""Writes an analog value (PWM wave) to a pin.
Args:
- pin(PWM1 to PWM6): A PWM pin
- value(int): Duty cycle, a value between 0 and 255
"""
global pwm_pins
if pin not in pwm_pins:
print "Pin must be one of:"
for key in pwm_pins:
print key
exit(1)
if value < 0 or value > 255:
print "Invalid duty cycle"
exit(1)
# 490Hz
period = 1000000/490
pulse_width = period*value/255
initMatch(0, period)
initMatch(pwm_pins[pin], pulse_width)
PWM_ChannelCmd(LPC_PWM1, pwm_pins[pin], FunctionalState.ENABLE)
PWM_ResetCounter(LPC_PWM1)
PWM_CounterCmd(LPC_PWM1, FunctionalState.ENABLE)
PWM_Cmd(LPC_PWM1, FunctionalState.ENABLE)
def add_channel(self, raw_channel, init_pulse):
"""Add PWM channel with a 1.5ms pulse.
"""
try:
channel = int(raw_channel)
if channel < 1 or channel > 5:
raise InputError
except:
self.log.warning("%s is an invalid channel." % raw_channel)
return None
# Check if channel has already been added
if channel in self.channels:
self.log.warning("Channel %d has already been initialized." % channel)
return None
self.channels.append(channel)
initMatch(channel, init_pulse)
PWM_ChannelCmd(LPC_PWM1, channel, FunctionalState.ENABLE)
#TODO: might need counter commands here. check this first.
self.log.info("Initializing BLDC pwm channel %d." % channel)
def __init__(self, config):
log = config.get('log_facility')
period = config.getint('bldc', 'pwm_period')
log.info("Set pwm period to %d" % period)
initMatch(0, period)
PWM_ResetCounter(LPC_PWM1)
PWM_CounterCmd(LPC_PWM1, FunctionalState.ENABLE)
PWM_Cmd(LPC_PWM1, FunctionalState.ENABLE)
self.log = log
self.config = config
self.channels = []
channels = config.getlist('bldc', 'channels')
init_pulse = config.getint('bldc', 'init_pulse')
log.info("Attempting to add channel(s) %s at pulse %d" % (channels, init_pulse))
for channel in channels:
self.add_channel(channel, init_pulse)
log.info("Initialized BLDC motor controller.")
def initPeriod(period):
initMatch(0, period)
def initPulse(channel, pulse_width):
initMatch(channel, pulse_width)
def initPeriod(period): initMatch(0, period)
def initPulse(channel, pulse_width): initMatch(channel, pulse_width)