FTDI breakout kills ATmega

Forum 2005-2010 (read only) Hardware Development
1

hi all,

i build a little Arduino compatible board with a atmega8 uc. i'm uploading the code with a ftdi connector (sparkfun) under ubuntu 9.04. in the beginning it works fine but after a couple of uploads (3-4) the ftdi kills the controller during or after uploading the code. and the serial port is greyed out in the serial port menu. the /var/log/messages shows
"kernel: [ 348.986078] ttyUSB0: 1 input overrun(s)" replugging the ftdi does not help. i have to restart the machine to use the ftdi again.
some chips just loose the code and i can reprogram it later. some are not programmable anymore. but sometimes it is possible to burn the bootloader (mkII) again but uploading code it not possible anymore. it seems that the tx/rx ports are killed.

i tried a couple of things:

  1. put a 1k resistor in-line the rx pin and another for the tx pin. like in the original Diecimila layout. without any result.
  2. to disable the dtr line with the same result.
  3. i enabled the brown-out detection fuse bit which helped to solve an other problem that was caused by the slow rising/falling power supply. (also erased the chip)

[EDIT] i tried the same now under windows xp. and it seems that the problem does not occur. is this a linux problem? avrdude? ftdi driver?

[EDIT2] currently the atmegas don't get killed (brown-out detection helped). just the ftdi gets unusable until a reboot.

am i overlooking something very basic? did anybody had similar problems?

i would be very thankful for help.

cheers,
ralf

btw: i use Arduino 0016 on ubuntu 9.04 and the sparkfun ftdi basic 5v adapter. power comes from a atx pc power supply.

2

my board layout

3

I've never had problems with FTDI cables or other breakout boards based on the chip on linux. I'm using openSUSE with 2.6.25.20-0.4-pae.

4

are you using avrdude/rxtx library packed with arduino? i tried to use a fresh installed arduino-0016. but didn't have luck.
it also seems to work fine under virtualbox and windows xp guest.

[EDIT]
when i try to upload via commandline and avrdude, i get:
avrdude: ser_open(): can't open device "/dev/ttyUSB0": Input/output error
but lsusb still shows:
005 Device 004: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) ICs the FTDI connector

[EDIT2]
putting an active usb extension cable between laptop and ftdi adapter solved the problem. maybe a dirty workaround. linux seems to be very thin-skinned dealing with interferences on the usb bus.

5

I just use V16 as it is. I had to install the avr-gcc packages and adjust RW perms (add to uucp group), but that's all. And I don't use 64bit, only trouble with that so far.