Arduino Forum

Products => Arduino GSM Shield => Topic started by: jtbennett on Apr 05, 2019, 02:59 am

Title: SIM900 Auto Power On w/ Pin D9
Post by: jtbennett on Apr 05, 2019, 02:59 am
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?
Title: Re: SIM900 Auto Power On w/ Pin D9
Post by: pert on Apr 06, 2019, 07:42 am
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.
Title: Re: SIM900 Auto Power On w/ Pin D9
Post by: jtbennett on Apr 09, 2019, 01:43 am
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