diff --git a/lib/ds3231.py b/lib/ds3231.py
index 1159d4a..5ec777f 100644
--- a/lib/ds3231.py
+++ b/lib/ds3231.py
@@ -1,4 +1,5 @@
 # Driver for ds3231 clock.
+#Uses I2C communication.
 
 import pyb, utime
 
@@ -21,7 +22,7 @@ class ds3231(object):
 
   def __init__( self, aLoc ) :
     """aLoc I2C pin location is either 1 for 'X' or 2 for 'Y'."""
-    self.rtc = pyb.RTC()
+    self.rtc = pyb.RTC() #Real time clock.
     self.i2c = pyb.I2C(aLoc, pyb.I2C.MASTER)
     self._buffer = bytearray(7)
     self.time(True)
diff --git a/lib/pca9865.py b/lib/pca9865.py
new file mode 100644
index 0000000..81e7f03
--- /dev/null
+++ b/lib/pca9865.py
@@ -0,0 +1,88 @@
+# MicroPython PCA9865 16 servo controller driver.
+
+import pyb
+from time import sleep_us
+
+class pca9865(object):
+
+  _ADDRESS = 0x40
+  _MODE1 = const(0)
+  _PRESCALE = const(0xFE)
+  _LED0_ON_L = const(0x6)
+#  _LED0_ON_H = const(0x7)
+#  _LED0_OFF_L = const(0x8)
+#  _LED0_OFF_H = const(0x9)
+
+#  _ALLLED_ON_L = const(0xFA)
+#  _ALLLED_ON_H = const(0xFB)
+#  _ALLLED_OFF_L = const(0xFC)
+#  _ALLLED_OFF_H = const(0xFD)
+
+  _DEFAULTFREQ = const(60)
+  _MINPULSE = const(150)
+  _MAXPULSE = const(600)
+  _PULSERANGE = const(450)
+
+  def __init__(self, aLoc) :
+    """aLoc I2C pin location is either 1 for 'X' or 2 for 'Y'."""
+    super(pca9865, self).__init__()
+    self.i2c = pyb.I2C(aLoc, pyb.I2C.MASTER)
+#    print(self.i2c)
+    self._buffer = bytearray(4)
+    sleep_us(50)
+    self.reset()
+
+  def read( self, aLoc ) :
+    return self.i2c.mem_read(1, self._ADDRESS, aLoc)
+
+  def write( self, aVal, aLoc ) :
+    self.i2c.mem_write(aVal, self._ADDRESS, aLoc)
+
+  def reset( self ):
+    self.write(0, _MODE1)
+    self.setfreq(_DEFAULTFREQ)
+
+  def setfreq( self, aFreq ) :
+    aFreq *= 0.9  #Correct for overshoot in frequency setting.
+    prescalefloat = (6103.51562 / aFreq) - 1  #25000000 / 4096 / freq.
+    prescale = int(prescalefloat + 0.5)
+
+    data = self.read(_MODE1)
+    oldmode = data[0]
+    newmode = (oldmode & 0x7F) | 0x10
+    self.write(newmode, _MODE1)
+    self.write(prescale, _PRESCALE)
+    self.write(oldmode, _MODE1)
+    sleep_us(50)
+    self.write(oldmode | 0xA1, _MODE1)  #This sets the MODE1 register to turn on auto increment.
+
+  def setPWM( self, aServo, aOn, aOff ) :
+    """aServo = 0-15.
+       aOn = 16 bit on value.
+       aOff = 16 bit off value.
+    """
+    #Data is on low, on high, off low and off high.  That's 4 bytes each servo.
+
+    loc = _LED0_ON_L + (aServo * 4)
+#    print(loc)
+    self._buffer[0] = aOn
+    self._buffer[1] = aOn >> 8
+    self._buffer[2] = aOff
+    self._buffer[3] = aOff >> 8
+    self.write(self._buffer, loc)
+
+  def setpin( self, aServo, aVal ) :
+    on = 0
+    off = min(aVal, 4095)
+    if off == 4095 :
+      on = 4096
+      off = 0
+    elif aVal == 0 :
+      off = 4096
+
+    self.setPWM(aServo, on, off)
+
+  def setangle( self, aServo, aAng ) :
+    """Set the angle 0-100%"""
+    val = _MINPULSE + ((_PULSERANGE * aAng) // 100)
+    self.setPWM(aServo, 0, val)