Getting status of serial ports (ttyS*) via linux terminal is simple:
sudo cat /proc/tty/driver/serial
Then it shows serinfo with list of all uarts with info about status and buffers. When I call
sudo cat /proc/tty/drivers
then I can see that rfcomm drivers are available:
rfcomm /dev/rfcomm 216 0-255 serial
And, of course, reading data comming from paired bluetooth device is not a problem.
The question is: how to get status of rfcomm serial ports (e.g. Blueotooth SPP devices)? Is this information available somewhere in the /proc directory like for ttyS* or could I use totally different way?
It depends what status you are looking for. The "rfcomm" command that comes with bluez does have some status info. It depends if that is adequate for you.
% rfcomm -h
RFCOMM configuration utility ver 4.101
Usage:
rfcomm [options] <command> <dev>
Options:
-i [hciX|bdaddr] Local HCI device or BD Address
-h, --help Display help
-r, --raw Switch TTY into raw mode
-A, --auth Enable authentication
-E, --encrypt Enable encryption
-S, --secure Secure connection
-M, --master Become the master of a piconet
-f, --config [file] Specify alternate config file
-a Show all devices (default)
Commands:
bind <dev> <bdaddr> [channel] Bind device
release <dev> Release device
show <dev> Show device
connect <dev> <bdaddr> [channel] Connect device
listen <dev> [channel [cmd]] Listen
watch <dev> [channel [cmd]] Watch
Related
I am trying alsa speaker-test utility after playing a .mp3 file using gst-play-1.0 in my customized Linux Os.but the speaker-test utility is unable to produce the sound over any channel and its producing a following error message given below.
speaker-test -p 1000 -t wav -c 6 -s 6
speaker-test 1.2.1
Playback device is default
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Playback open error: -16,Device or resource busy.
Based on my analysis, I found that the audio card/device "/dev/snd/pcmC0D0p" was used by gst-play-1.0 and its is not released even after gst-play-1.0 command execution.
I could see the result of lsof /dev/snd/* as
root 29u CHR 116,16 0t0 13359 /dev/snd/pcmC0D0p
Is anyone know how to release this resource so that I can use it for speaker-test ?
Your device is busy and your lsof shows about a process using the device, just that doesn't seems to indicate the exact command where this comes. Probably because of the CoreUtils your custom Linux uses for these tools, in this case lsof. Otherwise you will have a little more info, some output similar to this one:
$ lsof /dev/video*
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
gst-launc 20425 my-user 5u CHR 81,0 0t0 606 /dev/video0
As your lsof seems to indicate that someone is using that device, let's suppose it is an instance of speaker-test. So that you can just do a process search and kill that process to free the device; rerun lsof and see if the device is now available. If it is try again with your sound test!
ps aux | grep speaker
kill -9 <PID for Speaker>
lsof /dev/snd/*
Still asking about BLE devices and gatttool.
I'm able to send a char-write-cmd in interactive mode, but I'm not able to do the same in non-interactive.
This is what I send in interactive mode :
gatttool -I
[]> connect BTADDR
[BTADDR]> char-write-cmd 0x0040 01
[BTADDR]> exit
In this way I start the Alert service, which in my case makes the buzzer sounds.
In theory, the non-interactive mode should be:
gatttool -b BTADDR --char-write -a 0x0040 -n 01
But this do not send the request command event to the board, I'm checking it using a dev board.
The manual (non-interactive) way to read or write to your BLE peripheral:
To write and receive reply once: (depending on how you configure your BLE device)
sudo gatttool -i hci0 -b xx:xx:xx:xx:xx:xx --char-write-req -a 0x0025 -n ff
To write and receive reply indefinitely: (Until you disconnect from BLE device or stop your Bluetooth client)
sudo gatttool -i hci0 -b xx:xx:xx:xx:xx:xx --char-write-req -a 0x0025 -n ff --listen
Notice I only added the --listen option at the end. This mechanism only works if you configure your BLE node (sensor or actuator) to read and reply.
sources::
How to use gatttool non-interactive mode
Bluetooth Low Energy: listening for notifications/indications in linux
All that said, I still do not think it is best to control or get values from a BLE device. My direction is to move forward and use an API (maybe in python) to do the job for you.
https://github.com/peplin/pygatt
This API has been proven to work with Raspberry Pi Jessie destro.
Within a bash script, I use the following:
$ stty -F /dev/ttyUSB0 921600 raw
$ echo -n "some test data" >/dev/ttyUSB0
and it works as expected.
Using a PL2303 USB to RS232 adapter:
$ lsusb
...
Bus 006 Device 010: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 006 Device 011: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Now I tried to do the same with 1 MBd, but got an error:
$ stty -F /dev/ttyUSB0 1000000 raw
stty: /dev/ttyUSB0: unable to perform all requested operations
Also the same message when I try with 500 kBd. Trying 250 kBd the error message is different:
$ stty -F /dev/ttyUSB0 250000 raw
stty: invalid argument `250000'
Try `stty --help' for more information.
As seen here, it's a problem in the PL2303 linux driver.
I'm working on Kubuntu 12.04, 32 Bit. Unfortunally, I don't know how to fix that driver on my system (getting driver source, patch em, compile, install … hmm, maybe I learn a bit and give it a try - advice is welcome).
But maybe there is an updated driver avaliable which is easy to install?
Or does someone know an alternate USB to RS232 adapter which works at 1 MBd (hardware flowcontrol via rts/cts is needed, which works pretty well with the PL2303)?
After the realization that »Prolific and FTDI are competitors«, I bought Ftdi US232R-10 which is a FT232R based device and specified for 1 MBd transfer rate.
With this adapter I'd successfully tested communication at 1 MBd by transfering some GiB data without any error (including usage of Rts/Cts hardware flow control).
Configuring this device using stty like:
$ stty -F /dev/ttyUSB0 1000000 raw
works successfully.
Trying to solve this problem (ttyUSB0 that works properly than stop working after about 1hr)I'm thinking on if disconnecting and reconnecting the usb device could be a good fix.
So, it is possibile to cut down power to the USB device and repower it programmatically (bash)?
# lsusb -t
1-1:1.0: No such file or directory
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M
|__ Port 1: Dev 2, If 0, Class=vend., Driver=, 12M
|__ Port 1: Dev 2, If 1, Class=vend., Driver=cp210x, 12M
On am335x, kernel 3.2.0, ubuntu core armhf.
[ 1.784332] usb 1-1: cp210x converter now attached to ttyUSB0
At the moment I need a complete power cycle to have ttyUSB0 back.
This is the solution:
Find the identity of your usb device.
# tree /sys/bus/usb/drivers/cp210x/
/sys/bus/usb/drivers/cp210x/
|-- 1-1:1.1 -> ../../../../devices/platform/omap/musb-ti81xx/musb-hdrc.1/usb1/1-1/1-1:1.1
|-- bind
|-- module -> ../../../../module/cp210x
|-- remove_id
|-- uevent
-- unbind
So 1-1:1.1 is the identifier of my ttyUSB0(it can be discovered also via dmesg).
Then, disconnect the device (as root):
# echo -n "1-1:1.1" > /sys/bus/usb/drivers/cp210x/unbind
reconnect it
# echo -n "1-1:1.1" > /sys/bus/usb/drivers/cp210x/bind
At this point I had the same device but with a different name, it was now ttyUSB1 instead of ttyUSB0.
- To avoid this I added a new rule in /etc/udev/rules.d/ by creating a new file named 99-usb-serial.rules with this line:
SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea70", ATTRS{serial}=="002DCFAF", SYMLINK+="sameName", MODE:="0666"
where idVendor, idProduct and serial must be the values of your device. This rule will create a new device called sameName linked to the ttyUSB* device normally generated from the OS.
As #Robert Harvey Said,
You first need to find our driver that will help you 'unplug and plug' the usb. Type: ls /sys/bus/usb/drivers which should print something like this: btusb ftdi_sio hub usb usbfs usbhid usbserial_generic uvcvideo. These, are all the drivers for each usb device. Now, lets say mine is ftdi_sio, which is a device i use to program my arduino (atmega328p chip). I am not sure how Your/other usb devices name themselves there. Like, i dont know which of these is my mouse.
Now, you can see the driver's commands using:
ls /sys/bus/usb/drivers/ftdi_sio/, which will print something like: 1-4:1.0 bind module uevent unbind, Where 1-4:1.0 is the device's characteristic code, and the bind and unbind command, which are the 'plug' and 'unplug' command respectively.
Now, if i want to unplug programatically the ftdi usb port, i will type:
echo -n "1-4:1.0" > /sys/bus/usb/drivers/ftdi_sio/unbind
and, to plug it again:
echo -n "1-4:1.0" > /sys/bus/usb/drivers/ftdi_sio/bind
Now, we can combine all the commands together, with a ';':
echo -n "1-4:1.0" > /sys/bus/usb/drivers/ftdi_sio/unbind ; echo -n "1-4:1.0" > /sys/bus/usb/drivers/ftdi_sio/bind
I need to deal with two pieces of custom hardware which both send debugging data over two serial connections. Those serial connections go through two serial-to-USB converters. The serial-to-USB devices have the same vendor numbers, device numbers, and, apparently, the same serial numbers.
Here's the issue: I want to log the two serial ports separately. The custom hardware needs to be rebooted constantly, and whether they attach to the same /dev/ttyUSB* is completely random. How can I make them pick the same device path every time? I could make it dependent on what port it is plugged into, but that seems kind of hacky.
So, I ran a diff against the output of udevadm, like so:
$ udevadm info -a -p `udevadm info -q path -n /dev/ttyUSB1` > usb1
$ udevadm info -a -p `udevadm info -q path -n /dev/ttyUSB2` > usb2
$ diff usb1 usb2
The output of the diff is long; you can see it here
Grepping for serial (same for both):
$ udevadm info -a -p `udevadm info -q path -n /dev/ttyUSB2` | grep serial
SUBSYSTEMS=="usb-serial"
ATTRS{serial}=="0001"
ATTRS{serial}=="0000:00:1d.7"
Other info:
I'm using PuTTY to read from the serial ports.
OS:
$ uname -a
Linux xxxxxxxx.localdomain 2.6.32-279.14.1.el6.x86_64 #1 SMP Tue Nov 6 23:43:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
Please check if the usb-serial converter is based on a ftdi chip?
(You can check driver filenames)
If so; you have a chance to change serial number,or even the manufacturer info.
http://www.ftdichip.com/Support/Utilities.htm
Check the tools; MProg and FT_PROG utility tools.