Motors problem

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Motors problem

Postby madwhistler » Wed Mar 07, 2007 4:35 am

Ok, I have hammered NXJ alpha into submission on OSX :? and it now downloads into my brick. Here's the problem:

The first couple of times, my program seemed to work OK...the motors ran, and I learned to put a loop in main() and wait for the ENTER button so I could run things more than once :roll:

About the third time I ran the program, the motors refused to run. Not even a nudge. I saw my display codes, so I knew I was calling Motor.B.setSpeed(800); and Motor.B.forward(); -- but no action. Re-downloaded several times and pulled some hair out.

Finally decided to go back to the regular NXT firmware for a while, so I brought up the Mindstorms program and updated firmware. Downloaded my old Mindstorms (non-lejos) code, and guess what? NO MOTORS. :shock:

Some panic and more loss of hair, then I tried turning off and turning back on. Like magic, the motors are back running again! :D I repeated the test, loading the lejos firmware and program, verifying the motors don't work, reloading Mindstorms firmware, motors still don't work, restart, motors work. Yep.

So I'm guessing there's some odd state the motors can get left in that is non-functional, even through firmware reset...but something in the Mindstorms firmware start-up sequence clears the state. Any clues here? Anyone else seen this odd phenom?

Thnx...hey, I know it's alpha...

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Postby lawrie » Sun Mar 11, 2007 9:52 pm

This problem occurs when the ARM chip in the NXT stops talking to the AVR chip. This stops all motors and sensors (other than I2C sensors) from working. I don't know what is causing it in your case.

Removing and reinserting the batteries should always clear it.

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