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Topic: 'stty - F /dev/ttyUSB0 -hupcl' doesn't work in php (Read 2005 times) previous topic - next topic


I want to disable DTR (to avoid Arduino 10k autoreset) so I added the following code in php code to get this:

exec ("stty - F /dev/ttyUSB0 -hupcl'";

But it doesn't work: autoreset still works.

How I could disable DTR correctly via software (I use PHP)?



Feb 01, 2009, 04:48 am Last Edit: Feb 01, 2009, 09:04 pm by gnu_linux Reason: 1
An alternative would be to use a modern device / wulfden BBB Rev C without autoreset


The BBB Rev C kit sells for $13 and $2 shipping

You may also need a P4B RS232 to TTL adapter ( $5 ), or a BUB USB adapter ( $13 ), or an FTDI cable ( $20 ), if you don't already have one


Or you can build your own RS232 to TTL adapter from parts

"stty -F /dev/ttyUSB0 -hupcl" might work if you put it in an init script

If it doesn't work on USB try a real RS232 port with an RS232 to TTL adapter

Good luck :)


You have a space between the '-' and the 'F' in that code.  Is that intentional?  Doesn't look right to me...


Feb 01, 2009, 09:09 pm Last Edit: Feb 01, 2009, 09:11 pm by gnu_linux Reason: 1
Thanks Anachrocomputer you can see a lot better than I can :)

The correct command is

Code: [Select]

stty -F /dev/ttyUSB0 -hupcl

You should probably put it in an init script, however it may still not work

The user running the script must have the appropriate permissions to access /dev/ttyUSB0

/dev/ttyUSB0 is usually owner root and group uucp if you followed the arduino instructions

I still think you will probably get better results using a BBB Rev C where you can control autoreset in hardware


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