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     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/python-rpi-pyglow/stuff/vortex.py	Thu Apr 24 20:43:02 2014 +0200
     1.3 @@ -0,0 +1,71 @@
     1.4 +# Sample script for PiGlow that creates a continuous whirly vortex animation
     1.5 +#
     1.6 +# Please see our GitHub repository for more information: https://github.com/pimoroni/piglow
     1.7 +#
     1.8 +# Once running you'll need to press ctrl-C to cancel stop the script
     1.9 +
    1.10 +import time
    1.11 +from smbus import SMBus
    1.12 +
    1.13 +# command register addresses for the SN3218 IC used in PiGlow
    1.14 +CMD_ENABLE_OUTPUT = 0x00
    1.15 +CMD_ENABLE_LEDS = 0x13
    1.16 +CMD_SET_PWM_VALUES = 0x01
    1.17 +CMD_UPDATE = 0x16
    1.18 +
    1.19 +class PiGlow:
    1.20 +	i2c_addr = 0x54 # fixed i2c address of SN3218 ic
    1.21 +	bus = None
    1.22 +
    1.23 +	def __init__(self, i2c_bus=1):
    1.24 +		self.bus = SMBus(i2c_bus)
    1.25 +
    1.26 +        # first we tell the SN3218 to enable output (turn on)
    1.27 +		self.write_i2c(CMD_ENABLE_OUTPUT, 0x01)
    1.28 +
    1.29 +        # then we ask it to enable each bank of LEDs (0-5, 6-11, and 12-17)
    1.30 +		self.write_i2c(CMD_ENABLE_LEDS, [0xFF, 0xFF, 0xFF])
    1.31 +
    1.32 +	def update_leds(self, values):
    1.33 +		print "update pwm"
    1.34 +		self.write_i2c(CMD_SET_PWM_VALUES, values)
    1.35 +		self.write_i2c(CMD_UPDATE, 0xFF)
    1.36 +
    1.37 +	# a helper that writes the given value or list of values to the SN3218 IC
    1.38 +	# over the i2c protocol
    1.39 +	def write_i2c(self, reg_addr, value):
    1.40 +        # if a single value is provided then wrap it in a list so we can treat
    1.41 +        # all writes in teh same way
    1.42 +		if not isinstance(value, list):
    1.43 +			value = [value];
    1.44 +
    1.45 +        # write the data to the SN3218
    1.46 +		self.bus.write_i2c_block_data(self.i2c_addr, reg_addr, value)
    1.47 +
    1.48 +# a list of 18 values between 0 - 255 that represent each LED on the PiGlow.
    1.49 +# to change the LEDs we set the values in this array and then pass it to the
    1.50 +# update_leds() function to actually update the LDEs
    1.51 +values = [0x01,0x02,0x04,0x08,0x10,0x18,0x20,0x30,0x40,0x50,0x60,0x70,0x80,0x90,0xA0,0xC0,0xE0,0xFF]
    1.52 +
    1.53 +# create an instance of our PiGlow class and tell it that "1" is the I2C bus
    1.54 +# index (should be 0 for old old old Pis)
    1.55 +piglow = PiGlow(1)
    1.56 +
    1.57 +# loop forever, i mean why would we ever want to stop now the party has started?
    1.58 +# you can however use Ctrl+C to stop the script and reset the LEDs to off state
    1.59 +try:
    1.60 +        while True:
    1.61 +                # pop the first value off then drop it back on again - this just cycles the values around
    1.62 +                values.append(values.pop(0))
    1.63 +
    1.64 +                # update the piglow with current values
    1.65 +                piglow.update_leds(values)
    1.66 +
    1.67 +                # sleep for a bit, don't go too fast!
    1.68 +                time.sleep(0.1)
    1.69 +                
    1.70 +except KeyboardInterrupt:
    1.71 +	# set all the LEDs to "off" when Ctrl+C is pressed before exiting
    1.72 +        values = [0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00]
    1.73 +        piglow.update_leds(values)
    1.74 +