Re: [Ftdi-usb-sio-devel] Problems with FT245 on ttyUSB0

[Ralph L. <suc...@ih...>]

Also, is the board designed to operate with the FT245 in synchronous or
async mode?

The sync. mode requires the strobes on the FT245 to be driven
externally (e.g., by a microcontroller) - this is the default I think.

The easiest way to set the mode is probably to use libftdi - it has
python bindings.

Ralph.

On Thu, 18 Apr 2013 13:19:19 -0400
Ryan Neve <ne...@em...> wrote:

> I'm having trouble with a FT245RL based USB-relay board. It should be 
> easy enough to use. When I plug it in it appears as a serial port. I 
> send it three bytes which tell it what to turn on and off. E.g. 
> \xFF\x01\x01 turns on just relay 1 and \xff\x01\x00 turns everything off.
> 
> I wrote a very simple python program to test this on a Debian squeeze 
> machine:
> 
> import serial
> ser = serial.Serial('/dev/ttyUSB0') # Defaults to 9600 8N1
> ser.open()
> ser.write(chr(255) + chr(1) + chr(1))
> ser.close
> 
> ...and nothing happened no matter how much I fiddled. usually I get 
> nothing, and sometimes it blocks when I write. I installed the drivers 
> on a win7x64 machine, and changed one line to point to COM3, it works 
> great. I then tried it on a CentOS5 machine and it doesn't work here 
> either. I don't think it is permissions, I've added the users to the 
> dialout and uucp groups respectively. I've also tried it as root. I was 
> able to set up a udev rule on Debian which seems to work.
> 
> I'm wondering if there might be a problem with ftdi_sio? I'm a little 
> over my head, but I did this:
> 
> #/sbin/modprobe ftdi_sio vendor=0x403 product=0x6001 debug
> 
> and
> 
> #dmesg | grep ftdi
> [71621.091869] ftdi_sio ttyUSB0: ftdi_submit_read_urb - failed 
> submitting read urb, error -1
> [74607.375564] ftdi_sio ttyUSB0: ftdi_submit_read_urb - failed 
> submitting read urb, error -1
> 
> Ftdi has a Linux driver on their web site, but I think my kernels should 
> be new enough (2.6.33.7.2-rt30-1-686 and 
> 2.6.18-348.3.1.el5.centos.plusPAE) to not need it. If I do need it, is 
> there a guide on how to install available?
> 
> Thanks.
> -- 
> *Ryan Neve*
> University of North Carolina
> Institute of Marine Sciences
> 3431 Arendell St
> Morehead City, NC 28557
> (252) 726-6841 x179
> (252) 726.2426 Fax
>