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Topic: Standalone 328 - 8mhz, 3,3V problems (Read 831 times) previous topic - next topic

Erni

Mar 27, 2012, 08:49 pm Last Edit: Mar 27, 2012, 08:51 pm by Erni Reason: 1
I have build a breadbord Arduino according to this tutorial

http://arduino.cc/en/Main/Standalone

Everything works fine with a 16 Mhz crystal.

Next step was to make it run at 8mhz using 3,3 Volt, so i changed the crystal to 8mhz

I can burn the  bootloader using Arduino pro mini (8 mhz 3,3 V) with Atmega328
I can upload sketches

But only if I use 5V

If I use 3,3Volt I get the following error

avrdude: verification error, first mismatch at byte 0x0000
        0x0c != 0x00
avrdude: verification error; content mismatch


I have checked the fuses using avrdude:
Code: [Select]
avrdude: Device signature = 0x1e950f
avrdude: safemode: lfuse reads as FF
avrdude: safemode: hfuse reads as DA
avrdude: safemode: efuse reads as 5


I am using USBasp programmer, but i have tried Arduino as Isp with the same result
it IS a 328P-PU I am using

Any suggestions?

Coding Badly


Do you have AVCC and the second GND connected?

Erni

Yes

GND pin8 and GND pin 22 connected to ground
VCC pin 7, AVCC pin20, AREF pin21 to +5v (+3.3v)

I have also disconnected my LED on pin 13, because of the warning "Avoid lowimpedance loads when using the ICSP header"

Coding Badly

Quote
but i have tried Arduino as Isp with the same result


Are you adjusting the voltage level from the 5 V on the Arduino side to 3.3 V on the target side?

Erni

Quote
Are you adjusting the voltage level from the 5 V on the Arduino side to 3.3 V on the target side?


I must admit that I didn't think about that, so I will follow your method given here:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1258947348

use 5V when programming, that seems to be the easyest way. My project is to make a datalogger with SD card, and the 3.3V is a way to avoid the level shifting.

Thanks for the advice

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