Hello !
I need help, I played with the fuses of the 8U2 of my arduino uno, I have enabled the CKOUT (Enables Clock Output on PORTC7 as avr studio says)
I'm now unable to ISP the chip !
I'm using AVR Studio 4.18 build 684, with a avr500usb programmer. I tried severals ISP Frequencies, still nothing.
How to take back the control of my chip ?
I need help !
I think there is a provision to force a logic-level clock into the X1 pin so even if the oscillator settings are bad the chip will still run. Remember that SPI has its own serial clock so 'baud rate' is not something to worry about. Just set the SPI rate very slow. The SPI clock ON and OFF times must be at least 2 CPU cycles if the CPU clock is <12MHz and 3 CPU cycles if >12MHz, at least on the ATmega168.