Sorry for dumb questions. I have built several Arduino clones with Atmega168 and 328's. These were 5V/16MHz ones. Now i want to make a 3,3V/8MHz board for developing purposes. I have built it, with 8MHz crystal, appropriate power circuit, and so on. I grabbed an Atmega168 which had an 5V/16MHz bootloader installed. Put in the 3,3V board, and wanted to write a 3,3V bootloader in it, but Arduino IDE cannot communicate with the uC. The uC works great in the 5V developer board, i can write any bootloader in it, or upload programs, but in the 3,3V board, it does nothing. No serial communication, no communication via the ICSP header. No miswiring, i checked 100 times. I use DAPA programmer, which works great with the 5V board.
I tried erase the uC with uisp, but no success.
Has someone any ideas, what can be the problem?
(Can it be that i must re-fuse the uC for 3,3V bootloader writing? Or isn't the Atmega168 3,3V tolerant? My programmer, and RS232 converter use 5V TTL levels.)
Thanks for any help!