I am using an Arduino as ISP to program an Attiny85. Is there any way to disable the reset pin such that it is not functional. I think this is a fuse setting but I am not sure.

  • 1
    \$\begingroup\$ Keep in mind, you will need a high voltage serial programmer to reprogram the chip after you disable the reset pin. \$\endgroup\$
    – bitshift
    Sep 21, 2016 at 8:45
  • \$\begingroup\$ @bitshift is right, but I can tell you it's much easier all round if you just throw the chip in the bin and buy a new one instead of trying the high-voltage programming method. Keep a bunch of spare 85's nearby like I do! \$\endgroup\$
    – user98663
    Sep 21, 2016 at 8:48
  • \$\begingroup\$ I was aware of this. It seems there is no way to do this simply through the Arduino IDE or code. \$\endgroup\$
    – Kafros
    Sep 21, 2016 at 8:53
  • \$\begingroup\$ A bit lazy to toss them, make up your own HVP rig. It's really no trouble to do them. You can make the fuse change the last thing done in the makefile, or do it from the command line. Toss them when the pins break. \$\endgroup\$
    – mckenzm
    Oct 25, 2017 at 6:05

1 Answer 1


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There is indeed a fuse, it's called RSTDISBL and it's in the second out of three fuse bytes. See the Datasheet and note you wont be able to do ISP anymore.


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