[PLUG] USB Serial Port Adapters
Tim Wescott
tim at wescottdesign.com
Sat Jun 18 00:03:16 UTC 2011
On 06/17/2011 04:46 PM, Rich Shepard wrote:
> On Fri, 17 Jun 2011, Tim Wescott wrote:
>
>> Is there a way to map specific USB serial port adapters to specific device
>> names?
> Tim,
>
> Yep.
>
>> As far as I know, as I plug USB serial port adapters into the system
>> they'll appear as ttyUSB0, ttyUSB1, etc., in the order that I plug them
>> in.
> They tend to appear as pairs; e.g., ttyUSB0 and ttyUSB1.
>
>> But I want to have them show up as "ttyUSBcamera", "ttyUSBdata_aq", etc.,
>> or something similar -- so that when I plug in a _specific_ hardware
>> device, it maps to a specific device in the /dev directory.
> I used to have /dev/pilot defined for syncing my Palm (now Treo 700p), but
> that went away with the advent of udev. However, hardware does show up on
> consistent devices. For example, jpilot is set to connect on /dev/ttyUSB1,
> my thumb drives are defined in /etc/fstab as:
>
> /dev/sdb /mnt/thumb vfat noauto,users,rw 0 0
> /dev/sdc /mnt/flashdrive vfat noauto,users,rw 0 0
>
> which depends on which USB hole I use for it.
I think you misunderstand. I did an experiment: I started with my Fax
modem and the board I'm developing plugged in. I did ls /dev/ttyU*.
Then I unplugged the development board and did ls again. Then I plugged
in a debugger that has its own USB serial port adapter, and did ls
again. Here's my results:
tim at servo:~$ ls /dev/ttyU*
/dev/ttyUSB0 /dev/ttyUSB1
tim at servo:~$ ls /dev/ttyU*
/dev/ttyUSB0
tim at servo:~$ ls /dev/ttyU*
/dev/ttyUSB0 /dev/ttyUSB1
What _did_ happen is that at different times the same device -- ttyUSB1
-- got mapped to different physical devices. That is what I _do not_
want to happen. What I want to happen is to plug in the development
board and have /dev/ttyUSBdevelop appear, and to plug in the debugger
and have /dev/ttyUSBdebug appear (or some similar me-defined mapping).
Different devices. Different, _unique_, identifiers.
Otherwise, every time I plug a bunch of stuff in to the machine, I'm
going to have to do a bunch of hand work to figure out what ports map to
what devices at the moment.
--
Tim Wescott
Wescott Design Services
Voice: 503-631-7815
Cell: 503-349-8432
http://www.wescottdesign.com
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