The PEN pin

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#1
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I want to make sure I understand the PEN pin's function before I end up pulling it up with a resistor. The PEN pin is another way to force the Atmega chip into ISP mode. If CLK is held low and PEN is held low then the chip will enter ISP mode. All I need in order to disable this pin is use a pull up right?

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Quote:
All I need in order to disable this pin is use a pull up right?

You don't even need that, it is pulled high internally. If you are not going to use it, then do nothing with it.

Regards,
Steve A.

The Board helps those that help themselves.

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Our motto: Just say "No!" to connecting PEN.

It has been kicked around before; try searching out those discussions. Opinions vary somewhat, but PEN is a historical artifact and, like a mummy, best left undisturbed.

https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Koshchi wrote:
Quote:
All I need in order to disable this pin is use a pull up right?

You don't even need that, it is pulled high internally. If you are not going to use it, then do nothing with it.

I did. The search function is pretty iffy or Im horrible at searching. Is a pull up needed for the reset pin? Atmel recommends a 4.7K resistor.

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Have a read of AVR040 and AVR042 if making your own layout.

BTW a search for "PEN" currently hits 209 threads a number of which mention "PEN pin" in the thread title.

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clawson wrote:

BTW a search for "PEN" currently hits 209 threads a number of which mention "PEN pin" in the thread title

Thanks I was searching correctly. I didn't realize the default search is an or and not the typical and.