def set_servo(self, gpio, pulse_width_us):
"""
Sets a pulse-width on a gpio to repeat every subcycle
(by default every 20ms).
"""
# Make sure we can set the exact pulse_width_us
_pulse_incr_us = _PWM.get_pulse_incr_us()
if pulse_width_us % _pulse_incr_us:
# No clean division possible
raise AttributeError(("Pulse width increment granularity %sus "
"cannot divide a pulse-time of %sus") %
(_pulse_incr_us, pulse_width_us))
# Initialize channel if not already done, else check subcycle time
if _PWM.is_channel_initialized(self._dma_channel):
_subcycle_us = _PWM.get_channel_subcycle_time_us(self._dma_channel)
if _subcycle_us != self._subcycle_time_us:
raise AttributeError(("Error: DMA channel %s is setup with a "
"subcycle_time of %sus (instead of %sus)") % \
(self._dma_channel, _subcycle_us,
self._subcycle_time_us))
else:
init_channel(self._dma_channel, self._subcycle_time_us)
# Add pulse for this GPIO
add_channel_pulse(self._dma_channel, gpio, 0, \
int(pulse_width_us / _pulse_incr_us))
def set_servo(self, gpio, pulse_width_us):
"""
Sets a pulse-width on a gpio to repeat every subcycle
(by default every 20ms).
"""
# Make sure we can set the exact pulse_width_us
_pulse_incr_us = _PWM.get_pulse_incr_us()
if pulse_width_us % _pulse_incr_us:
# No clean division possible
raise AttributeError(("Pulse width increment granularity %sus "
"cannot divide a pulse-time of %sus") % (_pulse_incr_us,
pulse_width_us))
# Initialize channel if not already done, else check subcycle time
if _PWM.is_channel_initialized(self._dma_channel):
_subcycle_us = _PWM.get_channel_subcycle_time_us(self._dma_channel)
if _subcycle_us != self._subcycle_time_us:
raise AttributeError(("Error: DMA channel %s is setup with a "
"subcycle_time of %sus (instead of %sus)") % \
(self._dma_channel, _subcycle_us,
self._subcycle_time_us))
else:
init_channel(self._dma_channel, self._subcycle_time_us)
# If this GPIO is already used, clear it first
if self._gpios_used & 1 << gpio:
clear_channel_gpio(self._dma_channel, gpio)
self._gpios_used |= 1 << gpio
# Add pulse for this GPIO
add_channel_pulse(self._dma_channel, gpio, 0, \
int(pulse_width_us / _pulse_incr_us))
def pulse(self):
'''
The pulse width for the servo.
'''
position_ratio = self.angle / self.range
position_ratio *= -1 if self.reverse else 1
pulse_range = max(self.pulse) - min(self.pulse)
pulse_incr = _PWM.get_pulse_incr_us()
pulse = pulse_range * position_ratio + min(self.pulse)
pulse = pulse // pulse_incr
pulse *= pulse_incr
return pulse
def __init__(self, dma_channel=0, subcycle_time_us=20000, \
pulse_incr_us=10):
"""
Makes sure PWM is setup with the correct increment granularity and
subcycle time.
"""
self._dma_channel = dma_channel
self._subcycle_time_us = subcycle_time_us
if _PWM.is_setup():
_pw_inc = _PWM.get_pulse_incr_us()
if not pulse_incr_us == _pw_inc:
raise AttributeError(("Error: PWM is already setup with pulse-"
"width increment granularity of %sus instead of %sus")\
% (_pw_inc, self.pulse_incr_us))
else:
setup(pulse_incr_us=pulse_incr_us)
def __init__(self, dma_channel=0, subcycle_time_us=20000, \
pulse_incr_us=10):
"""
Makes sure PWM is setup with the correct increment granularity and
subcycle time.
"""
self._dma_channel = dma_channel
self._subcycle_time_us = subcycle_time_us
if _PWM.is_setup():
_pw_inc = _PWM.get_pulse_incr_us()
if not pulse_incr_us == _pw_inc:
raise AttributeError(("Error: PWM is already setup with pulse-"
"width increment granularity of %sus instead of %sus")\
% (_pw_inc, self.pulse_incr_us))
else:
setup(pulse_incr_us=pulse_incr_us)
def get_pulse_incr_us():
""" Returns the currently set pulse width increment granularity in us """
return _PWM.get_pulse_incr_us()
def get_pulse_incr_us():
""" Returns the currently set pulse width increment granularity in us """
return _PWM.get_pulse_incr_us()
