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 is_channel_initialized(channel):
""" Returns 1 if this channel has been initialized, else 0 """
return _PWM.is_channel_initialized(channel)
def is_channel_initialized(channel):
""" Returns 1 if this channel has been initialized, else 0 """
return _PWM.is_channel_initialized(channel)