Go Down

Topic: DisablingAutoResetOnSerialConnection for Duemilanove (Read 7967 times) previous topic - next topic

MartinP

Hi
I am having auto reset problems when connecting to a Mac using Windows 7. I found this way(s) to disable auto reset on connecting the USB cable. This appears to only deal with the ATmega168 and Diecimila.

http://arduino.cc/playground/Main/DisablingAutoResetOnSerialConnection

Will any of these methods work on a Duemilanove? and could this create any problems. My system works fine on a PC with Windows XP and also Windows 7.
Thanks
Martin

baum

Yep. The only difference between the two boards (I think) is a new atmega and some other small stuff- basic idea is the same.

Be adventurous! Try it! You can't hurt anything!

pluggy

An alternative to a resistor of a fairly specific value, is a small electrolytic capacitor in a wide value range (1uF - 47uF) between Gnd & Reset.  So long as its bigger than the autoreset capacitor its value doesn't really matter.  If its too big, it will delay the startup of the arduino when powering up due to the capacitor charging through the pull-up resistor in the reset circuit. 
http://pluggy.is-a-geek.com/index.html

MartinP


MartinP

The hardware solution did not work on a MAC + Win 7 running a VB6 App. I found a solution propsed by "jumpjack" at (old Forum) http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1213719666/60

Using this code in VB6 solved the problem of the MAC OS resetting my Arduino on opening the USB port:
   MSComm1.Settings = "9600,n,8,1"
   MSComm1.CommPort = 4
   MSComm1.InBufferCount = 0
   MSComm1.DTREnable = False
MSComm1.PortOpen = True

MartinP

The "MSComm1.DTREnable = False" does the trick
Martin

retrolefty

Or use a Seeeduino board, they have a manual switch to turn on or off the auto-reset feature.

http://garden.seeedstudio.com/index.php?title=Seeeduino_v2.21


MartinP

Unfortunately Seeeduino is not readily available in the Southern tip of Africa. Arduinos are stocked here.

rin3

As pluggy suggested, even as less as 0.1uF between RESET and GND worked for my boards, though I haven't tested the values less than that.
I've found also that plugging between RESET and +5V do the same trick.

Go Up