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Author Topic: $50 robot help with atmega168a  (Read 792 times)

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Offline Neogs RedTopic starter

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$50 robot help with atmega168a
« on: August 10, 2011, 12:10:11 PM »
hi, this is my first robot and when i started i decided to do all the uart modifications to the mcu, however after the uart modifications the robot's two primary drive servos were acting a little funky... they would start and stop continuously creating a vibrating effect through-out the whole chassis. after that, i just wiped the chip and added the original code with the appropriate modifications and now the robot just does not function at all. i have a good feeling this has something to do with the programming... ???

Offline corrado33

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Re: $50 robot help with atmega168a
« Reply #1 on: August 10, 2011, 02:34:57 PM »
Did you change the fuse values back to what they were originally?  More so, did you change the clock speed back to what it was originally?  

Clearing the chip would NOT set this back to normal, and it would most likely make your program useless. 

If you can still successfully program the chip, you haven't bricked it.... yet.  Be careful setting the fuses. 
« Last Edit: August 10, 2011, 02:36:54 PM by corrado33 »

Offline Neogs RedTopic starter

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Re: $50 robot help with atmega168a
« Reply #2 on: August 10, 2011, 03:12:22 PM »
i set the clock speed back to the original settings, but the fuses idea sounds like it could be the underlying problem. any idea how to get the original settings? and how do i check the fuse settings? ??? ???

Offline Neogs RedTopic starter

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Re: $50 robot help with atmega168a
« Reply #3 on: August 10, 2011, 04:27:14 PM »
nevermind.... it appears that i locked it up completely..... any way on resetting it?

Offline joe61

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Re: $50 robot help with atmega168a
« Reply #4 on: August 10, 2011, 04:51:23 PM »
nevermind.... it appears that i locked it up completely..... any way on resetting it?


When you say "locked up completely" do you mean you can't talk to it with your programmer? Or that you can program it but nothing happens, or something else?

If you can't connect with your programmer you might have gotten one of the clock bits wrong. Take a look at this for some possibilities.

Edit: Ask me how I know this works :-)

Joe
« Last Edit: August 10, 2011, 04:54:51 PM by joe61 »

Offline Neogs RedTopic starter

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Re: $50 robot help with atmega168a
« Reply #5 on: August 10, 2011, 05:25:50 PM »
well with that last post, it appears that i have turned off one of the clocksetting fuses. however ponyprog is giving me an error that it cannot read the chip itself. when i say locked up, i mean i cannot read or write anymore data to the chip, and when i hit the ignore on the read it shows me a hex file full of nothing but 0's. when i open up the security bits all the boxes are checked showing me that all the fuses are connected. i will try what that post said and see if i can't fix it that way... and i thought i was going to have something interesting to smash too... dang.  ;)

Offline Neogs RedTopic starter

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Re: $50 robot help with atmega168a
« Reply #6 on: August 11, 2011, 12:50:44 PM »
hey, i found this interesting forum on a "high voltage" programmer. comes with a wiring schematic and everything. it is designed for the atmega168, but apparently somebody was using it to reset their atmega328p's. the link is below.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1278784179

gonna build it and try it out on the 168a.

Offline corrado33

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Re: $50 robot help with atmega168a
« Reply #7 on: August 11, 2011, 05:36:01 PM »
You do realize that buying a new chip would probably be a lot cheaper.   :D

Have you tried a different programmer?  What have you tried? 

I had a chip that I couldn't read or write with one piece of software, but avrdude worked well. 

 


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