Hello, hopefully someone can help me with this.
Here is the problem: I am using an Arduino Ethernet http://arduino.cc/en/Main/ArduinoBoardEthernet with a Arduino Motor Shield R3 http://arduino.cc/en/Main/ArduinoMotorShieldR3. When starting up, meaning either connecting it to a powersupply (USB or power cable) or after a new sketch was uploaded, my motor connected to channel B runs crazy. This means, the speed (on PMW Pin 11) is set to high and the Direction (Pin 13) changes all the time, in a high frequency. Why is this a problem? Well I have a printermotor hooked up and on startup it runs on full power, changing it's direction many times and then just keeps running in one direction for 1-2seconds and therefor crashing in to the end of the rail.
This doesen't happen on channel A, (which uses other PINs) but I can't use that one, since I need the precious "interrupt" PIN3 for my encoder.
My guess is that it is the bootloader, since this phenomena appears even before the sketch loads. (I also tried it with the bareminimum sketch) Now, I found several hints for this problem:
- arduino.cc/forum/index.php/topic,51774.0.html - This post discusses, as I think, exactly my problem, but they found no solution. Also he states that the problem disappears when he connects the battery pack instead of the USB. But in my case, the external power cable produces the same problem.
- http://arduino.cc/en/Hacking/Bootloader?from=Main.Bootloader - It says:
The only differences is the time the bootloader waits for a new program to arrive and the number of times it flashes the pin 13 LED when it starts.
This would atleast explain the change in direction...
Does anyone have an explanation on why it does that? And wheather I can supress this in any way?
Thank you for your help!