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Topic: ATmega328 random reset (Read 1 time) previous topic - next topic

dc42

Three possibilities come to mind:

1. Lack of decoupling capacitors. See previous posts. The most important one is between Vcc and Gnd of the atmega328p. I suggest you solder one directly across the Vcc and ground pins of the chip, on the underside of the board, with really short leads.

2. Power supply brownout, e.g. if the peak fan current is too much for either the 7805 or the supply that is providing 12V. Need to know more about the fan and the supply before we can discount this as a possibility.

3. Software problem.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Docedison

#11
Jan 12, 2013, 07:29 pm Last Edit: Jan 12, 2013, 07:31 pm by Docedison Reason: 1
Somehow you missed this part...
Quote
The schematic was very good well laid out and almost perfect but it can't possibly work as drawn or designed. The CD4050 or 74HC4050 or whatever is a 5V part and I assume that the device was intended as a level shifter for the 3V3 SD card? Most of the ones I've seen are 3V3 interface and your level shifter Vcc is connected to 5 V defeating the level shifting, were it so you could have used one of the remaining 3 buffers for the MISO connection from the card to the controller.

Before that board is going to work you will have to fix the level shifter Vcc. If the CD4050 is seeing 5V as it's supply it will output 5V.. Not 3V3 as you need for proper operation.
{Edit}
Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

luxy


Before that board is going to work you will have to fix the level shifter Vcc. If the CD4050 is seeing 5V as it's supply it will output 5V.. Not 3V3 as you need for proper operation.
{Edit}
Bob


Oh my.. Hmm.

I saw that sd card module have voltage regulator for 3,3V. It uses AMS1117 and it should provide up to 1A current. Is it possible to use this voltage regulator for supplying 74HC4050? I think in my case this would be the easiest solution, if it could work that way of course.

luxy

I think i solved my problem.. 

Like i said in my previous post, now i am powering 74HC4050 through 3.3V regulator. I also added 0,1uF ceramic caps between VCC and GND of ATmega328, 74HC4050, 74HC595 and LCD. 

Up till now (after half an hour of testing) everything works fine, without problems.. And i hope it will stay that way :) 

Thank you for all guys! :D

Docedison

A Good Job, well Done.

Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

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