Reprogram with RESET used as IO pin

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#1
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While working on a design using an ATmega8, discovered we need one more I/O pin. The external RESET pin can become PC6 by programming the RSTDISBL fuse.
Both the serial and parrallel programming mode use the RESET pin.
Does this mean that once the fuse is programmed, the chip can only be reprogrammed by using a boot loader? :(

Laurence Boyd II

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After using Reset as an I/O pin, ISP programming will be unavailable.

In parallel programming mode, though, an illegal voltage is fed into the Reset pin -- this will override its function as an I/O pin. You'll still be able to program it using a high-voltage parallel programmer.

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Hi,

Quote:
an illegal voltage is fed into the Reset pin

I guess that means there is no protection diode to Vcc on that pin? If so, then you would need to be careful what you feed into PC6...is that correct?

Regards,
Steve