Question about Arduino embedding on circuit board.

Hi, I built a circuit using an lcd and temp sensor using the Arduino. It worked on the breadboard, but when I wired everything up to a perf board with new 328 chip (it had bootloader already on it, and I programmed it by inserting it into the dip socket of UNO), it didn't work. I triple and quadruple checked all of the connections. I am using an external 16 MHz crystal and two .1uF caps at the crystal. Can these capacitor values keep the circuit from running. Are they necessary?

Thanks,

Kevin

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colecago over 13 years ago +1

Yeah, those are way high. I think we used 18-22pF on our AVR designs. Here is a document from Atmel that talks a bit about crystal cap selection and other AVR recommendations. http://www.atmel.com/images…

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0 Blacksheep32 over 13 years ago

Any chance you could post up your circuit?
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0 e14 Contributor over 13 years ago in reply to Blacksheep32

Hi, the circuit has physical Atmega328 pins 7, 20, 21 to 5v. Pins 8 and 22 to ground. Xtal to pins 9 and 10 with .1uF caps. The RGB LCD is going to digital pins D3, and D5 thru D12 as well as appropriate vcc and ground and pot. The circuit worked when breadboarded along with the UNO. I have temp sensor on pin A0. Also reset pin is going to 5v thru 10K resistor

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0 shabaz over 13 years ago in reply to e14 Contributor

Perhaps one board was configured to use the internal oscillator. If it is desired to use an external crystal, the 0.1uF capacitors need to be replaced with something in the region of 22pF. If it still doesn't work then it can be investigated further, but definitely the external crystal does need a far lower value. Atmel devices can often be configured to use an internal oscillator, or an external crystal.
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0 shabaz over 13 years ago in reply to e14 Contributor

Perhaps one board was configured to use the internal oscillator. If it is desired to use an external crystal, the 0.1uF capacitors need to be replaced with something in the region of 22pF. If it still doesn't work then it can be investigated further, but definitely the external crystal does need a far lower value. Atmel devices can often be configured to use an internal oscillator, or an external crystal.
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