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Topic: Breadboard 328P Accepting Bootloader but failing Sketch upload (Read 5186 times) previous topic - next topic

nickgammon



The blue capacitors are the decoupling capacitors. They are required for reliable operation. In fact they should be closer than I showed there. Directly adjacent to the chip legs, not a couple of centimeters away.

I should have cut those blue and red wires shorter and put the capacitors next to the pins. However this particular setup worked.

Quote
Using Atmega_Board_Detector I DO have to press the reset button for it to work.


That's odd. Can you post a picture? I never have to press reset. Something is seriously wrong if you do. I should point out that the Atmega_Board_Detector holds /Reset low during programming (that's how you enter programming mode). However it does it programmatically. If you have to do it yourself there is something major wrong.
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

hiduino

#16
Jul 13, 2013, 12:52 am Last Edit: Jul 13, 2013, 01:11 am by hiduino Reason: 1

I have a 10 Kohm pull up resistor on the reset pin of the atmega.  The reset pins for the AVRISPMKII and Atmega_Board_Detector goes directly to the reset pin.  Using the AVRISPMKII I do not have to do anything and it works.  Using Atmega_Board_Detector I DO have to press the reset button for it to work.


Ahh, For the Atmega_Board_Detector, you need to use pin D10 to the reset on the m328p.(Not reset to reset)



I do NOT have a 0.1uF from the DTR pin to the reset pin.  Is this needed? I thought/hoped I could just hit reset before it started programming. 

That is fine, you don't need the reset capacitor.  You just need to time when you hit the reset button.

stephenholm

nbenm:  It worked ... do you happen to know why?  I put the two 10 Kohm pull up resistors on the two communication pins between the USB controller and the atmega chip.  Did that and bingo!  it works!  Is still am not using the .1 uF on the DTR pin, I'm just hitting reset instead.

Nick: I do have a 10 uF capacitor on the analog power circuit and it is right next to the pin.  On the power side I have the 4.7 uF I mentioned but it is closer to the power supply.  So you believe I should have the .1 uFs right next to the chip also?

hiduino: Understood, I had it wired incorrectly for the Atmega_Board_Detector.

Thanks again for all your help everyone!

nickgammon


Nick: I do have a 10 uF capacitor on the analog power circuit and it is right next to the pin.  On the power side I have the 4.7 uF I mentioned but it is closer to the power supply.  So you believe I should have the .1 uFs right next to the chip also?


Yes I do. The 0.1 uF filter a different frequency than the 4.7 uF.
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

hiduino


I put the two 10 Kohm pull up resistors on the two communication pins between the USB controller and the atmega chip.  Did that and bingo!  it works!


After reviewing the FT232RL breakout board from SparkFun, it turns out that it is running at default of 3.3v i/o levels which explains why the serial was not working correctly.  You have a mismatch of i/o voltage level interfacing to the m328P.  The 10K pull-up is probably biasing the level enough to work, but not the recommended way to do level conversion.


Docedison

The input clamp diodes will limit the input voltage to the lower Vcc.. But @ 3.6 V and above the data is well into the upper switch threshold range and should work fine although somewhat dodgy electronically...

Doc
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