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USB to DMX: alternate chipsets

Discussion in 'Lighting and Electrics' started by headcrab, Dec 23, 2010.

  1. headcrab

    headcrab Active Member

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    Are there drivers to allow USB to serial adapters based on the Prolific PL2303 chip to be used (with appropriate line drivers) to generate DMX? I find that I can get these for less than FTDI breakouts.

    To further cloud the water, later on the page someone says the cable uses the MCS7703 chip.

    Thanks in advance.
  2. n1ist

    n1ist Active Member Premium Member

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    Looking briefly at the data sheet for the PL2303, the driver doesn't support 250kBaud as an available baud rate, so I would guess that it won't work without some custom code (but the data sheet doesn't describe how to set a non-standard baud rate). As for cost, you can get a FTDI-based board with TTL output (good to drive a 75176 or similar RS485 driver) for about $10 to $15; they are commonly used as programming dongles for the Arduino. This will still only give you Enttec Open functionality, not Pro, so the quality of your DMX timing will be dependent on the PC and what Windows feels like doing.
    /mike
  3. headcrab

    headcrab Active Member

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    Thanks for the info. When I take that into consideration it seems like a lot more trouble and expense than just learning to hand-solder the FT232RL.
    I'm fine with processor-dependent bit-bashing, I won't be running a show with this.
  4. n1ist

    n1ist Active Member Premium Member

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    Look at Sparkfun's USB to RS-485 Converter. It's a readymade board with the FT232RL and RS485 driver; they also give the schematic and Eagle layout files. The pinout on the RJ45 output jack, however, isn't the DMX standard pinout, but you will probably want to wire it up to an XLR anyway.
    /mike

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