COM.LTE pin 2?

[aezero]

Hi all,

I have a number of COM.LTE modems running successfully with CoreBasic units. I was just going through some of my code to make a list of which pins are available for use when I noticed a reference to pin 2 during the modem initialization.

I see it show up in almost every sample config and forum post like this:

SerialAT.begin(115200, SERIAL_8N1, 5, 13); 
pinMode(2, OUTPUT);
digitalWrite(2, 0);
delay(3000);
digitalWrite(2, 1);

What is the purpose of pin 2 here? Many of the examples will have a comment along the lines of "set pin 2 high for using the modem (simulates a power button press)".

My code doesn't have the two digitalWrite lines, but a single modem.restart() and it has been working fine. As an experiment, I tried removing the pinMode(2, OUTPUT) line in my code and reassigning it as an input connected to a toggle switch, and everything still seems to be fine.

Thanks!

aezero

[felmue]

Hello @aezero

this code sequence is used to power on a given modem. Some types of modems power on automatically and other types of modems need a short pulse to turn on.

The SIM7600 used in COM.LTE is wired to automatically turn on - no additional pin is required for that. In other words you can use pin 2 for something else.

Thanks
Felix

[aezero]

@felmue Thanks, Felix! You're the best!