Adding bts7960 motor controller driver.

esp32/bts7960.py

@@ -0,0 +1,73 @@
+
+#Driver for the bts7960 43A high power motor controller.
+
+from machine import Pin, PWM
+from utime import sleep_ms
+
+class motor(  ):
+  '''Control a motor connected to the bts7960 motor controller.'''
+
+  _MAXDUTY = const(1023)
+
+  def __init__( self, aForward, aBackward, aFreq = 100 ) :
+    '''aForward = tuple (On Pin #, PWM Pin #)
+       aBackward = tuple (On Pin #, PWM Pin #)
+       aFreq = PWM freq.
+       #Example:
+       m1 = motor((19, 22), (21, 23))
+    '''
+    self._onf = Pin(aForward[0], Pin.OUT)
+    self._forward = PWM(Pin(aForward[1], Pin.OUT))
+    self._onb = Pin(aBackward[0], Pin.OUT)
+    self._backward = PWM(Pin(aBackward[1], Pin.OUT))
+    self._freq = aFreq
+    self._speed = 0
+
+  @staticmethod
+  def seton( aPin, aOn ) :
+    '''Set on/off (free wheeling) state of motor.'''
+    aPin.value(1 if aOn else 0)
+
+  @property
+  def frequency( self ) :
+    return self._freq
+
+  @frequency.setter
+  def frequency( self, aValue ) :
+    '''Set frequency for forward/backward PWM pins.'''
+    self._freq = aValue
+    self._forward.freq(self._freq)
+    self._backward.freq(self._freq)
+
+  @property
+  def speed( self ) : return self._speed
+
+  @speed.setter
+  def speed( self, aValue ) :
+    '''Set velocity and direction of motor with -100 <= aValue <= 100.'''
+    self._speed = aValue
+    pos = True
+
+    if aValue == 0 :
+      motor.seton(self._onb, False)
+      motor.seton(self._onf, False)
+      return
+    elif aValue < 0 :
+      aValue = -aValue
+      pos = False
+
+    motor.seton(self._onf, pos)
+    motor.seton(self._onb, not pos)
+    duty = (min(100, aValue) * _MAXDUTY) // 100
+    self._forward.duty(duty)
+    self._backward.duty(duty)
+
+  def brake( self ) :
+    '''Brake the motor by sending power both directions, then shut it all down.'''
+    self._forward.duty(_MAXDUTY)
+    self._backward.duty(_MAXDUTY)
+    motor.seton(self._onf, True)
+    motor.seton(self._onb, True)
+    sleep_ms(500)
+    self.speed = 0
+