Short Circuiting a RN-XV WiFly 171

I was troubleshooting my RN-XV WiFly RN-171 some more last night and I think I finally destroyed it. But I don't understand why. Just trying to learn from my mistakes. Unfortunately with hardware, mistakes are expensive.

My current set up:

  1. RN-XV WiFly RN-171 (
  2. Arduino Wireless SD Shield (
  3. Arduino Uno Rev 3

The Problem:

I'm trying figure out how I fried it. I think I short circuited it somehow. Because the WiFly no longer lights up.

Strangely it does power up if I hook a wire from 3.3V to the pin 1 or 3. It's strange.


So I was reading up some more on WiFly and compatibility with XBee shields (

Apparently there is an issue with a diode on pin 3 that causes problems with the WiFly. So I thought maybe that was an issue with Arduino Wireless SD Shield too.

Pin 3 on the WiFly 171 is RX. I believe that is DIN.

I read that a 10K pull up resistor was needed to bridge pin 1 and 3. I saw this in several places. Here is one example:

What I did to fry it

I wasn't sure how to attach the pull up resistor on the Wireless SD Shield, so I just took a 10K resister and tried to wrap the pins 1 and 3.

I wasn't getting a response, so I figured that I could attach one end of the resistor to 3.3V to pin 3. I tried this a few times and then finally I see the pwr led on the Wireless SD Shield light up red.

But then I realized the WiFly leds were no longer lit, so I quickly unplugged the Arduino. I removed the resister and then turned on the Arduino again. The lights on the WiFly were no longer lighting up.

As mentioned earlier, I am still able to power up the WiFly if I attach a jumper from 3.3V to pin 1 or 3. I don't quite understand what happened.

The only thing I can think is that I short circuited something.


My guess is you have fried the voltage regulator on the Wireless SD Shield. Have you checked that with a multimeter?

Thanks for the response pylon. I haven't check the shield with a multimeter yet. Mainly because I don't have one. I plan to buy one soon.

I thought I could forgo one of most basic tools in electronics, but clearly I need to read up on the basics more.

At least a basic multimeter is probably a must when doing electronics. The cheaper ones are only a few dollars and will fulfill your needs at the beginning.

Sketch Arduino for Wifly RN-XV modem configuration without Wifly library and
with front-end: