dmxftdi.py

from pyftdi import ftdi

#FTDI device info
vendor=0x0403
product=0x6001

#####################
# DMX USB controller
#####################
class OpenDmxUsb():
    def __init__(self):
        self.baud_rate = 250000
        self.data_bits = 8
        self.stop_bits = 2
        self.parity = 'N'
        self.flow_ctrl = ''
        self.rts_state = 0
        self._init_dmx()

    #Initialize the controller
    def _init_dmx(self):
        self.ftdi=ftdi.Ftdi()
        # self.ftdi.open(vendor,product,0)
        self.ftdi.open_from_url('ftdi:///1')
        self.ftdi.set_baudrate(self.baud_rate)
        self.ftdi.set_line_property(self.data_bits,self.stop_bits,self.parity,break_=0)
        self.ftdi.set_flowctrl(self.flow_ctrl)
        self.ftdi.purge_rx_buffer()
        self.ftdi.purge_tx_buffer()
        self.ftdi.set_rts(self.rts_state)

    #Send DMX data
    def send_dmx(self,channelVals):
        self.ftdi.write_data(channelVals)
        # Need to generate two bits for break
        self.ftdi.set_line_property(self.data_bits,self.stop_bits,self.parity,break_=1)
        self.ftdi.set_line_property(self.data_bits,self.stop_bits,self.parity,break_=1)
        self.ftdi.set_line_property(self.data_bits,self.stop_bits,self.parity,break_=0)

if __name__=="__main__":
    dmxUsb=OpenDmxUsb()

    channelVals=bytearray([0]*513)
    channelVals[0]=0 # dummy channel 0
    for i in range(512):
        channelVals[i]=255
        print('sending ', channelVals)
        dmxUsb.send_dmx(channelVals)