Hi.
I bought an ATmega328P chip from mouser. After soldering it to a PCB, it worked just fine, but the clock seemed to be 8 times slower than it should have been. I thought that the problem is with the fuses, so after searching for a bit I found the default fuses for the Arduino and uploaded them to my ATmega328p. Since then the USBaps cannot communicate with it.
I am using an 8MHz external crystal oscillator.
As far as I understand the fuses are both for 8MHz and the 16MHz versions of the Arduino, so my question is, do I have to change the crystal oscillator to a 16MHz one, or did I just brick the microcontroller?
Thanks for the help in advance!
The manufacturer ships chips with internal RC oscillator and the CKDIV8 fuses set.
If you are using an external oscillator, the fuses must be set for that, and the Arduino IDE must be informed of the frequency. See the data sheet for the details.
I know this, and I uploaded the fuses (LFUSE: 0xFF, HFUSE: 0xDA, EFUSE: 0x05) with AVRDUDESS.
Looks like you made one or more mistakes. Please explain what you believe those fuse settings to accomplish, the IDE settings, the details of the external oscillator and wiring, and describe the failure symptoms.
Well, using the LFUSE: 0xFF, I should be able to use an external crystal oscillator from 8MHz and above. The crystal oscillator I am using is a ECS-80-10-33-CHN-TR with a 22pF capacitor on the input and a 22pF capacitor on the output of the crystal.
The crystal oscillator in connected to XTAL1/PB6 and XTAL2/PB7.
As failure symptom, the microcontroller simply does not repsond.
Please post a complete schematic diagram of your setup and a photo of the assembled PCB. Do you have the required minimum circuitry, including reset pullup resistor and the decoupling capacitors?
See this "bare bones" getting started tutorial.
Here is the schematic, and yes I have all the minimum required components. As I was saying the board worked just fine before changing the fuses.
The reset pullup is not shown on the schematic. It is required.
Please post a complete schematic, including the crystal wiring, and a photo of the assembled PCB.
Forum members are happy to help, but to guess what might be wrong, generally need a complete picture of what you are doing. See the "How to get the best out of this forum" post for more information.
Hey, sorry I just disappeared. Turn out the crystal was not making a good contact on the board or when I installed it, I might have messed up its orientation. Now it is working just fine.
P.S: I had a 10kOhm resistor as a pull-up on the RESET pin.
Thanks for your help tho!
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