Trouble with analogWrite/serial and detecting Arduino

I have an Arduino Uno running on Ubuntu 10.10 (intel processor) (arduino-0021) IDE

I have no problems uploading to the arduino when it is only a digitalWrite command, but as soon as I upload a program to the Arduno that uses the analog commands it works fine on the arduino but I can no longer access the arduino through "Tools --> Serial Port --> /dev/ttyACM0"

Its like the program running on the Arduino is "hogging" the usb cable and I can no longer upload another file. If I am patient and try a few times I can finally upload another program that doesn't use the serial command or analog inputs and then it works fine until another serial type program is loaded then it does it again.

Is it my arduino, or my drivers, or the Arduino IDE, (arduino-0021)

same problem here, ubuntu 9.10 with arduino uno, with arduino ide 0022.

just uploaded my second program: a serial echo.

void setup() {
void loop() {
char c =;

/dev/ttyACM0 doesnt show up in the ide.
the TX led is glowing permanently.

Just got it today, and im afraid that i could have broke it :confused:

Uploading to ttyACM0 (if it shows up) gives my the error, that the programmer doesn't respond.

if i start the ide as root the ACM0 shows but if i upload it doesn't show me Done nor the blinking RX and TX on the board.

if you haven’t used any other wiring with your UNO, it can be ensured pretty easily that you haven’t screwed on your UNO(That’s definite.).

Time to do some googling. There is a fix to the bootloader for the UNO that fixes the inability to upload new code when the current code is flooding the serial port with data.

By the way,

void loop() {
char c =;

is just plain stupid. Reading data that isn't there is not real bright. There is a reason that there is a function to report how much data is available to be read.

with 2 new uno – both not the smd-version- i had same problems. and i am new with arduino. i updated the firmware using this site:

No guarantee, but both work fine now. i tried many times and problems seem to be gone .

I am using ubuntu 10.10 with an older IBM thinkpad T30.


good luck