added correction factor

darkwater_640/PCA9685.py

@@ -83,7 +83,7 @@ class PCA9685(object):
         self._device.write8(MODE1, mode1)
         time.sleep(0.005)  # wait for oscillator
 
-    def set_pwm_freq(self, freq_hz):
+    def set_pwm_freq(self, freq_hz, correctionFactor=1.0):
         """Set the PWM frequency to the provided value in hertz."""
         prescaleval = 25000000.0    # 25MHz
         prescaleval /= 4096.0       # 12-bit
@@ -91,7 +91,7 @@ class PCA9685(object):
         prescaleval -= 1.0
         logger.debug('Setting PWM frequency to {0} Hz'.format(freq_hz))
         logger.debug('Estimated pre-scale: {0}'.format(prescaleval))
-        prescale = int(math.floor(prescaleval + 0.5))
+        prescale = round(prescaleval * correctionFactor + 0.5)
         logger.debug('Final pre-scale: {0}'.format(prescale))
         oldmode = self._device.readU8(MODE1);
         newmode = (oldmode & 0x7F) | 0x10    # sleep

darkwater_640/darkwater_640.py

@@ -293,12 +293,12 @@ class dw_Controller:
         ININ = 0
         PHASE = 1
 
-        def __init__(self, addr = 0x60, freq = 100):
+        def __init__(self, addr = 0x60, freq = 100, correctionFactor = 1.0):
                 self._i2caddr = addr            # default addr on HAT
                 self._frequency = freq          # default @1600Hz PWM freq
                 # self.steppers = [ Adafruit_StepperMotor(self, 1), Adafruit_StepperMotor(self, 2) ]
                 self._pwm =  PCA9685(addr)
-                self._pwm.set_pwm_freq(self._frequency)
+                self._pwm.set_pwm_freq(self._frequency, correctionFactor)
                 # Just gonna default to high for now
                 GPIO.setmode(GPIO.BCM)
                 GPIO.setwarnings(False)