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Connect Orange PI One through USB OTG with a computer

reamond

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reamond

reamond

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Hi,

 

I would like to establish communication between Pi One and a computer through OTG Usb to USB. My goal is to use it to create a serial communication between the PI One and the computer to be able to send quick strings from the PC to the PI.

I have a program which only communicate through serial com port and I would like to feed it with data from the PI.

 

Is it possible... to use the physical interface to communicate?  Is it possible to establish serial communication between them?

 

I would be very grateful for any extensive help. 

Thanks in advance!

 

 

 

 

Hi again, 
I don't think I got closer to the solution... I don't want to use the debug port or the GPIO to create a fysical interface. What I would like to use USB<>Micro-USB cable to connect the otg port with a computer... And use the connection as a serial interface for communication. So, can anything like that work...? 
Thanks for your help and patience. /Regards 

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zador.blood.stained

zador.blood.stained

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Most probably @reamond meant OTG serial gadget (g_serial), which may not be activated in the kernel and also require patch similar to g_ether.

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reamond

reamond

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Hi,

 

I would like to establish communication between Pi One and a computer through OTG Usb to USB. My goal is to use it to create a serial communication between the PI One and the computer to be able to send quick strings from the PC to the PI.

I have a program which only communicate through serial com port and I would like to feed it with data from the PI.

 

Is it possible... to use the physical interface to communicate?  Is it possible to establish serial communication between them?

 

I would be very grateful for any extensive help. 

Thanks in advance!

Hi again, 

I don't think I got closer to the solution... I don't want to use the debug port or the GPIO to create a fysical interface.

 

What I would like to use USB<>Micro-USB cable to connect the otg port with a computer... And use the connection as a serial interface for communication.

 

So, can anything like that work...? 

Thanks for your help and patience. /Regards 

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tkaiser

tkaiser

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What I would like to use USB<>Micro-USB cable to connect the otg port with a computer... And use the connection as a serial interface for communication.

 

We added that to the kernel config yesterday. You find a pre-compiled kernel here (use dpkg -i *.deb to install followed by a reboot). Then please report back (and please also read through the commit comments what at least I would expect ;)

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rodolfo

rodolfo

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OPI ONE as serial gadget

 

 

Code snippets to enable/disable usb serial gadget on OPI ONE with Armbian_5.14

 

 

g_serial_start() {

echo -n 0 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
modprobe g_serial
echo -n 2 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
}

g_serial_stop() {

echo -n 0 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
rmmod g_serial
echo -n 1 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
}
 

On the OPI ONE side the serial port is /dev/ttyGS0

 

On the host side the serial port is /dev/ttyACM0

 

 

Testing the serial connection ( plug in USB-cable on host , new interface /dev/ttyACM0 is created )

 

( OPI ONE )

 

echo "xxxxxxxxxxxx hello from OPI xxxxxxxxxxxx" >/dev/ttyGS0

 

( host )

 

cat /dev/ttyACM0

 

( OPI ONE )

 

cat /dev/ttyGS0

 

( host )

 

echo "xxxxxxxxxxxx hello from host xxxxxxxxxxxx' >/dev/ttyACM0

 

( OPI ONE )

 

<ctrl><c> to close

 

 

Note on usage :

 

Only basic functions for simple serial communication tested. A quick test setting up a login console on /dev/ttyGS0 and conneting to it with screen /dev/ttyACM0

quickly showed the limits of g_serial gadget. To use it as a USB serial console does not make sense as g_ether provides a full fledged fast ethernet connection providing reliable network commmunication.

 

Enjoy !

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reamond

reamond

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Thanks for your add to the thread... I would need some more guiding, because I just can not make it work  :(

(. I take it up (ttyGS0 is created, and the OTG_ROLE is 2)... connect to my Mac..,which shows a new tty.usbmodem2411 connection.

I try to send a string as you did... but its not coming up with "cat" on the other side... not even on the PI ONE in an other terminal window.

Is it a config problem or I am just off the right path? Some print out about the port

ttySG0:

root@orangepione:/home/sdosa/DATA# dmesg | egrep -i 'serial|ttySG'
[ 7.088856] systemd[1]: Starting system-serial\x2dgetty.slice.
[ 7.105037] systemd[1]: Created slice system-serial\x2dgetty.slice.
[ 7.930490] systemd[1]: Starting LSB: controls configuration of serial ports...
[ 8.680042] systemd[1]: Started LSB: controls configuration of serial ports.
[ 8401.713876] g_serial gadget: Gadget Serial v2.4
[ 8401.713917] g_serial gadget: g_serial ready
[ 8409.225911] g_serial gadget: high-speed config #2: CDC ACM config
[ 9022.693175] g_serial gadget: high-speed config #2: CDC ACM config

root@orangepione:/home/sdosa/DATA# stty -F /dev/ttyGS0
speed 9600 baud; line = 0;
-brkint -imaxbel

tty.usbmodem2411:

stty -f /dev/tty.usbmodem2411
speed 9600 baud;
lflags: -icanon -isig -iexten -echo
iflags: -icrnl -ixon -ixany -imaxbel -brkint
oflags: -opost -onlcr -oxtabs
cflags: cs8 -parenb

Any hint where the problem should be... I just installed setserial to be able to administrate the port... but setserial seem to have problem to find it.

I know its not the topic of the thread... Please help me out to figure out the problem. /R

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rodolfo

rodolfo

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@reamond

 

Seems like the serial gadget is created ( /dev/ttyGS0 ) on OPI and does show up on the MAC side ( tty.usbmodemxxxx ). Without any further configuration OPI serial defaults to 115200 baud. For testing purposes work as root user ( sudo ) and retry the simple procedure outlined above . It is tested and works on the OPI side - you might have to google the OS-X part. Good luck.

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reamond

reamond

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Hi, Unfortunately I back again... Its just not giving any result... no matter what I try. To eliminate the problem I just concentrated on the OPI,

with two terminal windows...one in one out. But no matters what I do... nothing I can see trough the CAT command. 

I followed your lead on all points... but nothing. Can I somehow verify that all components are in place and arbian have no issue...

dont really know, just fishing. I tried to use "setserial" (installed), but its did not even see it (it see ttyS0, but not ttyGS0).

So now I am stuck... have no idea what causing the problem, that I can not even establish a "local loop" for verification.

Any hint which way should I search in the darkness?


I try to set the baud rate (looks like the port is on 9600), but it can not even change it!

root@orangepione:/home/cdosa# stty -F /dev/ttyGS0 38400
stty: /dev/ttyGS0: unable to perform all requested operations
 

 

The rest shows my attempt to show what I fed in... 

root@orangepione:/home/cdosa# ls /dev/ttyGS*
/dev/ttyGS0
root@orangepione:/home/cdosa# ls -l /dev/ttyGS0
crw-rw---- 1 root dialout 247, 0 Jun 30 17:23 /dev/ttyGS0

root@orangepione:/home/cdosa# stty -F /dev/ttyGS0 -a
speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff
-iuclc -ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt
echoctl echoke

root@orangepione:/home/cdosa# echo "xxxxxxxxxxxx hello from OPI xxxxxxxxxxxx" >/dev/ttyGS0

root@orangepione:/home/cdosa# setserial -g /dev/ttyGS0
Cannot get serial info: Invalid argument

 

 

 So thats it... no luck for me yet. /R

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rodolfo

rodolfo

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Just rechecked the steps outlined in previous posts so there must be something different in your setup. Connect Armbian device ( OPI ) to Linux host and you should be able to communicate when the /dev/ttyACMx shows up on the host without any need of setting up serial parameters ( baud rate, parity, flow control etc...). On the OS-X side this would require a suitable (acm) driver for the specific interface that shows up when you plug in the USB cable. Best of luck - you're close.

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