snir nisim

how to dissable ttyUSB0 loopback

Discussion created by snir nisim on Apr 9, 2012
Latest reply on Apr 9, 2012 by snir nisim

hello every one,

i've connected an arduino1280 board using usb to the QSB.

i've check the FTDI driver which is needed for the arduino board to recognized as serial port and that works fine.

i've also compiled my progrem to the board.


my env vars has been set like this:


setenv bootcmd_obds 'ext2load mmc 0:1 0x70800000 /unit_tests/obds.bin; go 70800000'

setenv bootargs_base 'setenv bootargs console=ttymxc0,115200'

setenv bootargs_nfs 'setenv bootargs ${bootargs} root=/dev/nfs ip= nfsroot=${serverip}:${nfsroot},v3,tcp'

setenv bootcmd_net 'run bootargs_base bootargs_nfs; tftpboot ${loadaddr} ${kernel}; bootm'

setenv bootargs_mmc 'set bootargs ${bootargs} root=/dev/mmcblk0p1 rw rootwait'

setenv bootcmd_mmc 'run bootargs_base bootargs_nfs bootargs_mmc; mmc dev 0; mmc read ${loadaddr} 0x800 0x2076; bootm'

setenv bootcmd 'run bootcmd_mmc'



the problem is that whenever the arduino board is sending a message it automatic loops back instead of being read() by the progrem.

the oposite way works just fine (the progrem sends with write() command to the arduino).


it seems that the usb acting as a output channel and loopback for input.

how to i make it to work in full duplex?


the arduino is just a developing platform for atmel's atmega1280 and it's using FTDI usb to serial converter (as i mentioned, i've added this driver to the kernel config...)