Merge pull request #337 from sourcebots/servo

Update servo limits, numbers and defaults for servo fw 4.4

Author: inventor02

sbot/servo_board.py

@@ -16,10 +16,11 @@
     get_USB_identity, map_to_float, map_to_int,
 )
 
-DUTY_MIN = 500
+DUTY_MIN = 300
 DUTY_MAX = 4000
-START_DUTY_MIN = 1000
-START_DUTY_MAX = 2000
+START_DUTY_MIN = 350
+START_DUTY_MAX = 1980
+NUM_SERVOS = 8
 
 logger = logging.getLogger(__name__)
 BAUDRATE = 115200  # Since the servo board is a USB device, this is ignored
@@ -77,7 +78,7 @@ def __init__(
         self._serial = SerialWrapper(serial_port, BAUDRATE, identity=initial_identity)
 
         self._servos = tuple(
-            Servo(self._serial, index) for index in range(12)
+            Servo(self._serial, index) for index in range(NUM_SERVOS)
         )
 
         self._identity = self.identify()