Re: Problems with some of the examples

["E.S. Rosenberg" <es.rosenberg+libftdi.i2net@xxxxxxxxx>]

Hi Ian,
I am running ola on ubuntu gnome 14.10, may switch to 15.04 soon, no problems (at the moment I run from git, but I recall successfully installing debs too).

Rui who is also on this list afaik and me have worked on the OLA plugin to control ftdi chips.

In ola the MAB is done with a libftdi call, my guess as far as your python stuff goes is that you are suffering from timing issues since at least as far as I understand so far you have to do timings....

Have a look at the implementation of FtdiInterface here:
https://github.com/Keeper-of-the-Keys/ola/blob/ftdi_scratch/plugins/ftdidmx/FtdiWidget-libftdi.cpp#L314

They recently pulled my changes and now I need to do cleanup when I have time.... (which is being problematic).

HTH,

Eli

2015-03-02 21:59 GMT+02:00 Ian Carr-de Avelon <carrdeavelon@xxxxxxxxx>:

I'd first like to thank both E.S. Rosenberg and Ryan Tennill for coming back to me. I'd seen OLA while skimming for solutions and the Python API looks good. It would be a sledge hammer to crack a nut, but one of the nice thing about open source is you never have to take second best because it's cheaper. I'd found it a problem because I'm in Ubuntu 14 and support does not seem to have got beyond 12. On the recommendation I fired up an older system, but could not get it to work with the interface I have.

I think that my way to go is pylibftdi as a wrapper to libftdi and I think I'm just 2 steps (maybe only one!) away from home.

I'm attaching 2 scope traces:

One is of the interface running under vendor supplied  windows software (which says it's an Enttec Open DMX USB)  and it controls a DMX light ok.

The second is of me controlling it with python. It is what I would call CW, like an old style morse code key switching on a sinusoid. Does anyone look at that and immediately know what is going on? Is it a function available of the ftdi chip or something else. I may have to take a screw driver to it and void the guarantee.

It looks to me like if I can swap it from the CW mode, I may be able to generate the initial DMX break and MAB by switching to serial with no stop bits and sending 0x00,0x00,0x00,0x0F then switching the stop bits on for the data. Otherwise, I'll have to sort out which line is which in bit-bang mode and add micro-sleeps.

Yours

Ian

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