Arduino Forum

Using Arduino => Microcontrollers => Topic started by: Vincent19 on Feb 06, 2013, 02:35 pm

Title: Attiny 85
Post by: Vincent19 on Feb 06, 2013, 02:35 pm
Dear friend,

recently I get myself some attiny85. So, by referring to the datasheet, it mention it has 6 programmable I/O. But I just only can see there are 5 programmable IO only. Is it that the RESET pins also can be the IO  ?

Thanks
Title: Re: Attiny 85
Post by: strykeroz on Feb 06, 2013, 02:39 pm
Hi,

Yes it is possible to reassign the reset pin as an IO pin, but you won't be able to reprogram your ATTiny85 in the usual way after that, as the reset pin is required for that.  If you're using the Arduino IDE you'll typically treat it as 5 + reset + the two power pins.

What are you hoping to use them for?  It's possible you can work around this limitation.

Geoff
Title: Re: Attiny 85
Post by: Erni on Feb 06, 2013, 02:39 pm
Quote
Is it that the RESET pins also can be the IO  ?

Yes it can, but if you use it as IO, you cannot reprogram the chip unless you use a High Valtage programmer

Ups, sorry strykeroz, I was too slow
Title: Re: Attiny 85
Post by: Vincent19 on Feb 06, 2013, 02:40 pm
USBasp consider HVP ? Oh, so for normal usage, I onyl can use 5 pins ?

Thanks
Title: Re: Attiny 85
Post by: fungus on Feb 06, 2013, 03:08 pm

Oh, so for normal usage, I onyl can use 5 pins ?


Realistically? 5 pins is the limit, yes. 6 pins needs special hardware to program it.

PS: You can use the RESET pin as an analog input so long as you don't take the voltage low enough to cause a reset :)