Strange motor movement - Sanguinololu

Hey all,

I got a problem: after setting up my rig (Prusa Mendel, sanguinololu with stepsticks, atx power supply, sprinter firmware) I loaded up pronterface to do some calibration. Everything worked fine after a few adjustments to the configurations.h, all accept the x axis. It moves only one direction, to the left, when I press both x- and x+ , both move to the left.

After a bit of troubleshooting, I swapped cables and it did it on the other motor, swapped drivers and it still did it on the x axis. This seems to point to the board, so I consulted the schematic and traced the x-direction pin for the driver to the corresponding pin on the atmega644. My meter says the continuity between them is sound. So I'm figuring its a bad atmega644. I double checked all my solder joints.

Did I miss something? Is there a way to test the pin on the chip before replacing it? Any advice?

It's very frustrationing to come so close and hit a wall that involves ordering another part and waiting a few more days.

I know how you feel - I recently had a rather major incident with my board so that I am having to replace most of the semiconductors.

Unfortunately, I am not very good at configuring firmware, but I can try anyway:

Check the Configurations.h file again for any mistyped or wrong options.

If you can, reinstall the firmware.

If none of these turn anything up, it would probably be best to just order a new one. Be sure to check Ebay (if you aren't using it already) in case there are any cheaper options available.

-SC

P.S. Also try testing or replacing the X-axis stepper driver with another one that you know works.

As well as checking for continuity you also need to check for shorts.

You can test the atmega by inserting it in the socket with that pin bent out and then measure the voltage on it when moving + and -.

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[www.hydraraptor.blogspot.com]

thanks for the help.

does anyone know if there is an unused pin i can reassign as the xdirection in hte pin assignments?

There are spare pins connected to the expansion connector that you could use. Have a look at the schematic.

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[www.hydraraptor.blogspot.com]

well, borrowed an used pin (D17) and connected it to the D21 pin socket after bending the D21 up out of the way, reassigned D17 to x direction and it works. I finally have both directions on the x axis. this will have to be a temporary fix until i can replace the chip.

thanks for the help.

Edited 2 time(s). Last edit at 07/11/2012 03:45PM by Ej.

thanks for your last comment.

I have the same problem and you help me to found a temporary solution.

No problem.

Have you seen this: [forums.reprap.org]

this evening i love you !!!!!!

but i don't understand how to modify JTAG

can you explain me, please ? (for a noob....)

Sorry, I haven't tried it yet. Still using my work around, and dealing other problems.

I'll look into and maybe try soon. As a fellow noob, we're all in this together.