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Topic: [SOLVED] Sketch won't load after power off/up, need to reset (Read 2085 times) previous topic - next topic

kahuna0k

May 09, 2011, 11:29 pm Last Edit: May 13, 2011, 10:45 pm by kahuna0k Reason: 1
I have got two Arduino UNO Model R2, and have built a Photoduino shield following instructions http://code.google.com/p/photoduino/ and have the following problem. I can flash the firmware provided in the Photoduino page without problems, and it works. But if I power off the Arduino and then power on it (either using USB or external power adaptor) it does not work, it seems that the bootloader does not load the sketch. If I reset the Arduino it works again, until the next poweroff. I have tried the following:

Upgrading firmware using dfu-programmer following: http://arduino.cc/en/Hacking/DFUProgramming8U2
Upgrading bootloader following: http://marcoramilli.blogspot.com/2011/03/arduino-uno-bootloader-fix-aka-30k.html

still not working.

I have also tried to flash a simple sketch, Blink, and it seems to work even after powerof without need of reset. But if I plug the photoduino shield Blink sketch start failing the same as Photoduino sketch, and start needing a reset after poweroff.

Could anybody take a look at the Photoduino project to detect any incompatibility with Arduino UNO R2? The Photoduino is working perfectly with other Arduino boards. I have images of everything under http://flic.kr/s/aHsjuHUKJs

Grumpy_Mike

It could because your power supply dose not come on quickly enough to trigger the auto reset circuit. Try a power supply with more current capability.

kahuna0k

I'm using a 9V 500mA adapter, and have also tried with the USB port, neither of them work. Also as I have said the Blink sketch, works out of the box. Could it be that the photoduino shield needs more current that available from the 500mA adapter and the autoreset circuit gets disabled?

Grumpy_Mike

So load up the blink sketch into the arduino.
Does that work from power up?
Add the photoduino shield nothing more, and nothing attached to the shield.
Does it now require a reset before the blink will start?
If so there is something wrong with the shield's construction. There is nothing in the schematic that would affect the reset.
The other possibility is that your computer is not initialising the COM port correctly on plug in, but if you get the same effect from just powering it up with a 500mA supply then it points to the shield.

kahuna0k

It seems that you were right and the problem is the autoreset circuit, I followed your instructions and found that everything works without problems while there is no LCD connected so maybe it has something to do with power, as I suppose the LCD is the more power hungry element there. Both blink and photoduino  (just checking the buzzer and the switches, as the LCD need to be unplugged) are working even after power recycling. I have tested two LCDs one of them is http://www.display-elektronik.de/DEM16216SYH-LY.PDF, anyway it seems that it has nothing to do with arduino UNO itself, firmware or bootloader.

Grumpy_Mike

Has the LCD got a backlight you are trying to power, if so have you got a current limiting resistor in series with it?

kahuna0k

I thought that the photoduino shield take care of this itself, but I have soldered a variable resistor to the pin 16 in serial with the cable, and I get the same result, even when increasing the resistor enough to have no backlight. Any other idea?

Thanks!

Grumpy_Mike

Well if it is the auto reset circuit then you could try upping the size of capacitor linking the DTR signal to the reset line. Fortunately all you need to do is to solder another capacitor across the existing one. A 0.1uF would double it but you could try anything up to 1.0uF depending on what you have on hand.

kahuna0k

It seems that I has solved it. I have break the trace in RESET-EN and now everything works as expected, I don't really understand how it works, because I thought RESET-EN was what was not working and causing the malfunction.

Regards

gerschu

hi, same problem here.
how did you solve the no-reset issue ?

thx,

gerhard

gerschu

Thanks, cutting the bridge solved my reset problem, too

efspi


It seems that I has solved it. I have break the trace in RESET-EN and now everything works as expected, I don't really understand how it works, because I thought RESET-EN was what was not working and causing the malfunction.

Regards


Good evening, I have the same problem, but i can't understand what I must do to solve it!

Can you explain me with a drawing?

Thank's a lot!

Grumpy_Mike

Quote
It seems that I has solved it. I have break the trace in RESET-EN and now everything works as expected,

This is odd because it removes the auto reset.

Now you will not be able to upload a sketch without holding down the reset button and releasing it at the right moment.

It doesn't make much sense unless you have a wiring error when you made the shield.
While it might appear to be working I don't think you have got to the root of your problem.

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