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Topic: Please help, error from Arduino shield board[Solved] (Read 887 times) previous topic - next topic

littleming

Feb 14, 2013, 05:43 pm Last Edit: Feb 15, 2013, 06:18 pm by littleming Reason: 1
Dear All,

I fabricated a shield board for the Arduino Mega. I guess I may use some ATMega communication pin because I cannot upload the program to Mega directly within my shield board. I need upload the program to Mega first, then insert back the shield board, the function for both board would be Okay. Otherwise, the error would appear "avrdude:stk500_getsync(): not in sync:resp=0x00."

The PWM pin 2 to 13, all of the power pins, analog in pin 5 to 7, digital pin 22, 24, 32, 34, 44, 46, 52, 53 are used. The Tx, Rx pin are empty.

How can I solve that problem. Please help me.

Thank you very much.

PaulS

Can you upload to the Mega without your shield in place?


littleming

I check the datasheet it only mention Tx and Rx cannot be used. Otherwise, the program cannot upload to the Arduino board. But, any other pins would affect the program uploading excepted Tx and Rx for Mega board?

PaulS

Quote
But, any other pins would affect the program uploading excepted Tx and Rx for Mega board?

Perhaps because you have created a short circuit, or are demanding more current that the Mega can provide, or a host of other reasons. Other that "handmade" and that it uses a lot of pins, you've said nothing about your shield.

littleming

My shield board is connected with Mega1280 by using jumper. The PWM pin 2 to 13, all of the power pins, analog in pin 5 to 7, digital pin 22, 24, 32, 34, 44, 46, 52, 53 are connected to my board.

I don't think there are demanding too much current because I have not insert any IC into the shield board. And both shield board function and Mega function are Okay when I install back the shield board after the Mega download the program from USB without shield.

littleming

#6
Feb 15, 2013, 06:25 pm Last Edit: Feb 15, 2013, 06:28 pm by littleming Reason: 1
Thank you guys. I solved the problem. The reset circuit of my shield board is affected the program downloading. At the beginning, I found my reset circuit is wrong, +5V -> push button parallel 10uF  -> reset pin series 8.2k resistor -> ground, then I removed the resistor. I think it should be Okay because the reset pin is floating again. However it is wrong!!!

Now I cut the jumper between the Mega reset pin and shield board reset circuit. Everything is alright!!

littleming

But, now I have another question is why the Arduino would run normal when I connected a wrong reset circuit to the reset pin after I have uploaded program.

liudr


But, now I have another question is why the Arduino would run normal when I connected a wrong reset circuit to the reset pin after I have uploaded program.


I was reading your post and had a fear you never figured out why since you posted nothing regarding your shield but good thing you did find out what was causing the problem. Now to the why:

The reset pin needs to be toggled to low then back to high before program upload so arduino resets and runs bootloader that takes the sketch. If you have a huge capacitor like that 10uF and a large resistor like 8.2K, the time to discharge to 0V (maybe 0.5V) will be huge. I calculated 0.19 seconds, that's like human response time. I don't have the number (how soon after reset the computer sends out the secret knock) at hand but suspect the cap is the problem. On arduino dev board, there seems to be no cap (well there is one but not hooked up the way you did).

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