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[Lcdproc] lcdproc v0.5.3 - ConnectionType=ftdi [[ Segmentation fault ]]

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  • From: santanu at (Santanu Das)
  • Subject: [Lcdproc] lcdproc v0.5.3 - ConnectionType=ftdi [[ Segmentation fault ]]
  • Date: Sun, 24 Oct 2010 20:21:42 +0100

Hi Markus,
> [ ... ]
> Displays like Mplay (or Crystalfontz or MatrixOrbital) usually have the
> display connected to a microcontroller instead which takes care of
> displaying the data. That MC has to be connected to the computer somehow.
> One common way is to use a FT232 to connect the MC to the PC using USB. On
> the PC side the display appears as a serial port to which an application
> (like LCDd) can send/read data.
I think, that's exactly what it does; it uses FT232 USB to COM chip.

> If your display appears like a serial port to the OS and the Mplay
> sub-driver does not work, there may be an issue with the driver itself or
> you have a type of display which the sub-driver does not know how to talk
> to.

It appears to be a serial device to the system; this in the

root at htpc:~# ls -l /dev/serial/by-id/
total 0
lrwxrwxrwx 1 root root 13 2010-10-24 19:59
usb-FTDI_FT232R_USB_UART_A600dyfH-if00-port0 -> ../../ttyUSB0

Also in the dmesg, it appears as an USB Serial device:

root at htpc:~# dmesg | grep -i serial
[ 0.449409] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 0.449533] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 13.157754] usbcore: registered new interface driver usbserial
[ 13.157769] USB Serial support registered for generic
[ 13.157847] usbcore: registered new interface driver usbserial_generic
[ 13.157849] usbserial: USB Serial Driver core
[ 13.160189] USB Serial support registered for FTDI USB Serial Device
[ 13.160251] ftdi_sio 3-1:1.0: FTDI USB Serial Device converter detected
[ 13.161692] usb 3-1: FTDI USB Serial Device converter now attached to
[ 13.161755] ftdi_sio: v1.5.0:USB FTDI Serial Converters Driver

I tried "mplay" driver before, which didn't work. I can try again.
Actually, for LIRC I had to modify the hw_mplay.c as well for the remote
to work.

> I will have a look at the Mplay driver, but I will be away for a few days.

Thanks for that, I really appreciate it. Just let me know if any other
info you may need to make it work.


> Regards
> Markus
> -------- Original-Nachricht --------
>> Datum: Sun, 24 Oct 2010 02:28:37 +0100
>> Von: Santanu Das<santanu at>
>> An: lcdproc at
>> Betreff: Re: [Lcdproc] lcdproc v0.5.3 - ConnectionType=ftdi [[
>> Segmentation fault ]]
>> Hi Markus,
>>> Hello Santanu,
>>> please note that the hd44780 FTDI connection type is for use with FT2232
>> or FT245 FIFO chips and requires special wiring.
>> From the various source of reading, it does look like the display/IR is
>> based on FTDI FT232R USB to serial chip. What kind of "special wiring"
>> you are talking about? Although I connect the display directly to a
>> internal USB header; is it possible that the "wiring" is done internally?
>> Cheers,
>> Santanu
>>> Unless you know that your MPlay device makes use of these, the hd44780
>> ftdi connection is probably not what you are looking for.
>>> You may try hd44780's 'mplay' connection type instead.
>>> See
>> for more information.
>>> Regards
>>> Markus
>> _______________________________________________
>> LCDproc mailing list
>> LCDproc at

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