Is there a way to program the Attiny44 on a FabISP board using an Arduino board? I read through a few online tutorials, and the ones that even mention using the Arduino as an ISP for an Attiny44 don't mention the issue of programming a chip that's meant to be clocked at a different speed (12 MHz)than the Arduino itself.

I would like to do this with the components I have if at all possible; I'm a poor student with no job, and I've unfortunately spent a lot of money on parts already. I also don't know anyone who has an AVR programmer, so that's out of the question.


  • \$\begingroup\$ The ISP speed is different to the clock rate which is probably why it's not mentioned. Did you have a link or two to the tutorials you're looking at? As long as it allows the ISP clock rate to be reduced to a suitable speed it should be OK. \$\endgroup\$
    – PeterJ
    Feb 12, 2014 at 3:41

1 Answer 1


Section 19 of the ATtiny24/44/84 datasheet, "Memory Programming", subsection 5, "Serial Programming", gives the minimum pulse width for ISP. Based on the values given (a minimum of 3 clock pulses for high and low each for a system clock >= 12MHz) the ISP clock must be no higher than 2MHz. As long as you can find a programming algorithm that respects that (and most do), you can use it to program the device.

  • \$\begingroup\$ But I would have to change fuses, no? How would that be done? \$\endgroup\$
    – xanadu
    Feb 12, 2014 at 4:43
  • \$\begingroup\$ With the lfuse, hfuse, and efuse memory types in AVRDUDE. \$\endgroup\$ Feb 12, 2014 at 4:44

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