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Topic: SIM900 Auto Power On w/ Pin D9 (Read 427 times) previous topic - next topic

jtbennett

Hi - I have a SIM900 shield sitting here (the one with the yellow and red pin headers) and I was reading that I could turn on the shield via software by connecting Pin 9 from the shield to pin D9 on the Arduino and doing 1s High, 5s low.

Is it absolutely necessary for me to use Pin D9 on the Arduino? I have a Mega with a TFT shield taking that one up, so I have some Analogs and digital pins from 22 up - no 9.

What's special about D9?

pert

As long as you update your code accordingly, you can use any free pin. If the pin number is hardcoded into a library, that is a little more tricky than just editing your sketch, but it's not too difficult.

jtbennett

As long as you update your code accordingly, you can use any free pin. If the pin number is hardcoded into a library, that is a little more tricky than just editing your sketch, but it's not too difficult.
OK great - I'll give it a try then! Thanks

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