libftdi Archives

Subject: Re: FT232R DMX512

From: Thomas Jarosch <thomas.jarosch@xxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Wed, 17 Nov 2010 20:37:57 +0100
Hello Rui,

On 10/26/2010 07:51 PM, Rui Barreiros wrote:
>  * Loop start
>  - ftdi_poll_modem_status
>  - if we got a break
>      - read startbyte (1 byte)
>      - read dmxvalues (512 bytes)
>  - ftdi_usb_purge_buffers
>  * Loop end
> Now, the dmx values are read, but, in the wrong place and sometimes change 
> places. The break detection is not working well, sometimes it's detected 
> other times it isn't, so the update is slow as hell for a 250k baud and I'm 
> almost sure that due to the break issue the values come in a wrong order.
> I could use FTDI own driver, I have an example using Win32 API that works 
> (all those FT_W320_* functions) but I can't make this work with libftdi, and 
> I'd rather use libftdi instead of FTDI own lib.
> Anyone has any idea or pointer to enlighten me over what I might be doing 
> wrong ?

I'm not sure if the ftdi_poll_modem_status() function
gives you access to all sent break signals. Look
into ftdi_read_data(), it filters out the modem status
on every packet border IIRC.


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