AR300M, GPIO and PCIE or RESET

I have acquired an AR300M and am thinking of using it in IoT applications.

I need access to the serial console, but can use the I2C pads as GPIO. Which gives me 2 IOs.

But when I look at the motherboard (https://www.gl-inet.com/ar300m/#1442566013976-f19448f7-2698), I note that GPIOs 15, 11, 8-3 are not mentioned.

Might they be in any way connected to the “PCIE” connector? If some of them are, that would make the device much more capable, in terms of IOs.

In addition, GPIO13 is connected both to a LED and to a switch. Could that circuitry be clarified)

 

Thanks in advance

updated the pintout. The button is GPIO3, not 13.

We nearly used all the GPIO and I don’t there is any spare GPIO left.

I have used a generic usb to rs232 adaptor with no problems (cheapest I could find on Amazon). A quick search on Google shows quite a few usb to gpio cards that present as rs232 so I guess these will work well. This would be a pretty good solution.