Programming FabISP Attiny44 with Arduino

Question

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.

Thanks!

• PeterJ: 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.

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.

• xanadu: But I would have to change fuses, no? How would that be done?
• Ignacio Vazquez-Abrams: With the lfuse, hfuse, and efuse memory types in AVRDUDE.