Using RESET as IO port

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#1
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Just want to verify if I am reading correctly
On the ATmega8, by programming a fuse the RESET pin can be used as PC6
Since the serial and parallel programing modes us the RESET, if this fuse is programmed, the chip can only be reprogrammed by the boot loader.
Further, since the fuse bit can not be written by the boot loader, once it is programmed, there is no way to undo it.

Is this correct, or have I missed something :?:

Laurence Boyd II

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You have missed the alternate method of parallel programming in the data sheet, p. 221.
Dave Raymond

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I have no experience with the ATmega8 but have programmed the ATtiny15 using parallel programming mode once the RSTDISBL fuse has been programmed.

According to page 225 of the ATmega8 datasheet dated 10/04, parallel programming can be used with the reset pin being used as an I/O as long as you can supply 11.5 to 12.5 Volts to the reset pin. It looks like PD7-PD1 and PC2 are also used for parallel programming.

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Thanks :) , I hadn't looked very closely at the parallel mode. but I can see where +12 could take control.

Laurence Boyd II