Attiny45 Pin State on Power Up

Discussions on the software and hardware for Atmel's STK standard.

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nvxwax
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Attiny45 Pin State on Power Up

Post by nvxwax » Mon Oct 20, 2014 11:25 am

What is the pin state during power up, Im using an ATtiny45 to control a few relays and when powered up it turns them on for a short time, once everything is settled everything runs fine, they are being controlled via pulse width from a RC radio, is there a way to force the output pins to stay high or low during power up?

Thanks

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leon_heller
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Re: Attiny45 Pin State on Power Up

Post by leon_heller » Mon Oct 20, 2014 2:33 pm

I/O pins are tri-stated on reset. You will have to pull them up or down with resistors if you want them to have a known value on power up.
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nvxwax
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Re: Attiny45 Pin State on Power Up

Post by nvxwax » Mon Oct 20, 2014 5:25 pm

I pull them low to control the relays, how and what resistor would I use to keep them high on reset?

jremington
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Re: Attiny45 Pin State on Power Up

Post by jremington » Mon Oct 20, 2014 5:43 pm

100K to Vdd on each input pin should work well.

nvxwax
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Re: Attiny45 Pin State on Power Up

Post by nvxwax » Mon Oct 20, 2014 6:05 pm

Thanks, I'm kinda new to all of this, it's nice not to get such help for a simple question lol

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