power.py

import struct


OUT_H0, OUT_H1, OUT_L0, OUT_L1, OUT_L2, OUT_L3 = range(6)


class Battery(object):
    def __init__(self, handle):
        self.handle = handle

    @property
    def voltage(self):
        """Voltage in Volts"""
        return round(self._get_vi()[0] / 1000.0, 2)

    @property
    def current(self):
        """Current in Amps"""
        return round(self._get_vi()[1] / 1000.0, 2)

    def _get_vi(self):
    	""" Measured in mA and mV"""
    	result = self.handle.controlRead(0x80, 64, 0, Power.CMD_READ_batt, 8)
    	current, voltage = struct.unpack("ii", result)
    	return voltage, current

class Outputs(object):
    def __init__(self, handle):
        self.handle = handle

    def __setitem__(self, index, value):
    	if index > 5 or index < 0:
    		raise Exception("Setting out-of-range rail address")

    	if value:
    		val = True
    	else:
    		val = False

    	cmd = Power.CMD_WRITE_output0 + index
    	self.handle.controlWrite(0, 64, val, cmd, 0)


class Power:
    CMD_WRITE_output0 = 0
    CMD_WRITE_output1 = 1
    CMD_WRITE_output2 = 2
    CMD_WRITE_output3 = 3
    CMD_WRITE_output4 = 4
    CMD_WRITE_output5 = 5
    CMD_WRITE_runled = 6
    CMD_WRITE_errorled = 7
    CMD_WRITE_piezo = 8
    CMD_READ_output0 = 0
    CMD_READ_output1 = 1
    CMD_READ_output2 = 2
    CMD_READ_output3 = 3
    CMD_READ_output4 = 4
    CMD_READ_output5 = 5
    CMD_READ_5vrail = 6
    CMD_READ_batt = 7
    CMD_READ_button = 8

    def __init__(self, path, busnum, devnum, serialnum = None):
        self.serialnum = serialnum

    	self.ctx = None
        self.handle = None

        self.battery = Battery(self.handle)
        self.output = Outputs(self.handle)

    def __repr__(self):
        return "Power( serialnum = \"{0}\" )".format( self.serialnum )

    def set_run_led(self, status):
        pass

    def set_error_led(self, status):
        pass

    def read_button(self):
        pass
    	# result = self.handle.controlRead(0x80, 64, 0, Power.CMD_READ_button, 4)
    	# status, = struct.unpack("i", result)
    	# if status == 0:
    	# 	return False
    	# else:
    	# 	return True
    
    def buzz_piezo(self, duration, frequency):
        pass

    def beep(self, duration, note=None, frequency=None):
	notes = { 
	    'c': 261, 'd': 294, 'e': 329,
	    'f': 349, 'g': 392, 'a': 440,
	    'b': 493, 'uc': 523
	}
        if note is not None:
	    note_frequency = notes.get(note.lower())
	    if note_frequency is not None:
                self.buzz_piezo(duration, note_frequency)
            else:
                raise ValueError('{} is not a recognised note.'.format(note))
        elif frequency is not None:
            self.buzz_piezo(duration, frequency)
        else:
            raise ValueError('`note` must be either a recognised note character or `frequency` an integer frequency.')