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Topic: [SOLVED] Set Low Fuse Bit, Now Can't Program over ISP (Read 6 times) previous topic - next topic

Aakash

Nick,

I installed your sketch and hooked up the ICSP lines and the only serial output I got was "Atmega chip detector." I also tried connecting D9 to XTAL1 through a 1.5K resistor and the same was outputted.

Should I be doing something differently?

Thanks,
Aakash

Nick Gammon

I wouldn't worry about the resistor, but that sounds OK, assuming you followed my wiring. Sounds to me confirmation that it isn't responding to programming.

I wonder if, when you were changing the fuse in the Atmel Studio, you accidentally didn't notice that at the same time the high fuse was set to something that wasn't appropriate (like SPIEN). Once you turn off SPIEN you can't program through the SPI interface.

Aakash

#27
Nov 18, 2012, 05:44 am Last Edit: Nov 18, 2012, 05:46 am by Aakash Reason: 1
Nick,

AVR Studio read in the existing fuses, and showed me that only the low fuse had been modified (the field shows up with a notice once you modify it)

So, I'm pretty confident that I didn't change anything except low fuse.

Thanks though. 
Aakash

Nick Gammon

OK, well I would remove the resonator if that is possible. Then feed the clock (XTAL1) from the clock output on my test sketch with no resistor. No capacitors or anything on XTAL1 or XTAL2. Check the voltages on the other pins (VCC, AVCC). Use the logic analyzer to confirm you are getting the 8 MHz clock in, and that the SPI data is arriving on the correct pins.

Do you have decoupling capacitors on VCC, AVCC?

Aakash

Nick,

I do have decoupling caps on both. I'll have to buy a hot air gun to remove the resonator. I'll order one and update this thread in a few days.

Thanks,
Aakash

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