Raspberry Pi communicating with I2C PWM chip CAT9532 (16-bit Programmable LED Dimmer)

rpi-cat9532.py

###############################################################################
# rpi-cat9532.py
#
# Author: electronut.in
#
# Description:
#
# Raspberry Pi communicating with I2C PWM chip CAT9532
# (16-bit Programmable LED Dimmer)
#
###############################################################################

import sys
import smbus
import time

# registers
INPUT0 = 0x00
INPUT1 = 0x01
PSC0 = 0x02
PWM0 = 0x03
PSC1 = 0x04
PWM1 = 0x05
LS0 = 0x06
LS1 = 0x07
LS2 = 0x08
LS3 = 0x09

# test based on CAT9532 data sheet example
# LED 0-3: ON
# LED 4-7: Dimming 30%, Blink 1: 152 Hz, 30% duty cycle
# LED 8-11: Blink at 2 Hz, 50% duty cycle (Blink 2)
# LED 12-15: OFF
def test1():
  bus = smbus.SMbus(1)
  addr = 0x60
  # auto increment (AI) flag is set to 0
  bus.write_byte_data(addr, 0x02, 0x00)
  bus.write_byte_data(addr, 0x03, 0x4d)
  bus.write_byte_data(addr, 0x04, 0x4b)
  bus.write_byte_data(addr, 0x05, 0x80)
  bus.write_byte_data(addr, 0x06, 0x55)
  bus.write_byte_data(addr, 0x07, 0xaa)
  bus.write_byte_data(addr, 0x08, 0xff)
  bus.write_byte_data(addr, 0x09, 0x00)
  return

# main() function
def main():
  # use sys.argv if needed
  print 'starting CAT9532 comms...'
  print 'press Ctrl-C to exit.'
  bus = smbus.SMBus(1)
  addr = 0x60

  # set Blink 0 frequency
  # T_BLINK0 = (PSC0 + 1)/152
  # 0 for always on
  bus.write_byte_data(addr, PSC0, 0)

  # set PWM0 to 50 %
  bus.write_byte_data(addr, PWM0, 128)

  # set LED 7 to Blink 0
  bus.write_byte_data(addr, LS1, 0b10000000)

  # set Blink 1 frequency
  # T_BLINK1 = (PSC1 + 1)/152
  # for f = 3 Hz, PSC0 = 152/3 - 1 = 50
  bus.write_byte_data(addr, PSC1, 50)

  # set PWM1 to 50 %                                                           
  bus.write_byte_data(addr, PWM1, 128)

  # set LED 8 to Blink 1
  bus.write_byte_data(addr, LS2, 0b00000011)

  while True:
    try:
      # generate duty cycle array for 0-255-0
      # to "pulse" the LED intensity
      vals = range(0, 256, 10)
      vals = vals + vals[::-1]
      for i in vals:
        bus.write_byte_data(addr, PWM0, i)
        time.sleep(0.025)
    except IOError, err:
      print err
    except KeyboardInterrupt:
      # turn off LEDs
      bus.write_byte_data(addr, LS1, 0x0)
      bus.write_byte_data(addr, LS2, 0x0)
      print 'bye...'
      exit()

# call main
if __name__ == '__main__':
  main()