PN532 not working
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PN532 not working

by Ryuske on Tue Oct 29, 2013 12:06 am

So I just received my PN532 breakout board today, and I wired it all up, soldered the pins to the best of my abilities (except for the jumper pins). And when I try and load up the readMifare example from here https://github.com/adafruit/Adafruit_NFCShield_I2C (after downloading that obviously) when I start up the Arduino and open up the Serial Monitor it says
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Hello!
Didn't find PN53*


I have check all the connections numerous times, I have looked a lot of different pictures to make sure everything is connected right and it all looks right to me. I have tried placing resistors inline with the TX/RX like I read somewhere, and I have tried pretty much every jumper combination I could think of. I really have no idea what is going on, and I'd really like to get this working. I order this RFID chip because I couldn't get my last one (SM130) re-flashed to I2C :/

All of this is on an Arduino UNO R3, and here are some pictures. I tried to take the best pictures I could, but they still may not be the best, sorry.

Image

Image

Image
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Re: PN532 not working

by Ryuske on Tue Oct 29, 2013 4:14 am

So after playing with it some more, I've noticed a few things (still doesn't work). The first being that I was looking at the code and the pins didn't really seem to be matching up so I looked at that for a while and realized that all the wiring examples were for SPI, not I2C. Which is fine, I found the SPI library and switched to that. All the pins make sense now, so that is good.

However, I did notice that I had some of the pins wired up backwards. This is what was wrong, and this is how it is now. (the pictures above are not longer accurate for this 1 pin).
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Arduino Pin 3, goes to
NXP 4050 pin 13, which then goes to
NXP 4050 pin 12, which finally goes to
PN532 breakout board pin MOSI/SDA/TX

This is what it looks like now:
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Arduino Pin 3, goes to
NXP 4050 pin 11, which then goes to (notice the change here)
NXP 4050 pin 12, which finally goes to
PN532 breakout board pin MOSI/SDA/TX


Oh, and I checked the continuity of my solder joints to the actual PN532 chip and they were all good. So that eliminates one of my doubts. However, I'm still confused about the jumpers (but even after switching to the SPI library I, again, tried all the combinations I could think of).

Thanks for reading! Any input even if it's just brainstorming is greatly appreciated, cause I'm stumped :/
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Re: PN532 not working

by adafruit_support_bill on Tue Oct 29, 2013 6:45 am

With the exception of the Arduino pin 3 connection change you noted, the connections in the pictures look right. But breadboard connections are never the most reliable. Double check that each wire is firmly gripped in the board for a solid connection.

Also, the solder joint on the GND pin looks suspicious. Usually when the solder balls up like that, the solder has not flowed well onto the surrounding solder pad. Check here for tips to fix that: http://learn.adafruit.com/adafruit-guid ... n-problems
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Re: PN532 not working

by Ryuske on Tue Oct 29, 2013 4:39 pm

Hmm, alright. I will work on the ground solder, but would it not be flowing even if the power LED comes on and I checked all the pins with their respective pin on the PN532 chip and all seemed right.

But I'm willing to try anything so I'll play with the ground solder some more.

Thanks!
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Re: PN532 not working

by Ryuske on Tue Oct 29, 2013 5:48 pm

I did it! I made it work, woohoo! Sorry, I am really excited I've spent the last 2 weeks trying to get any kind of RFID thing working and this is the first one that read a tag.

So, for anyone reading this here is the conclusion of what I found:
    Check your solder joints. The link above was amazingly helpful.
    The silkscreens are still backwards (as of 10/29/2013), so to jumper for SPI you have to do SEL0 OFF and SEL1 ON, and I2C is SEL0 ON and SEL1 OFF
    Check your wiring, and make sure you know what you're wiring for. The examples all use SCK, MISO, MOSI and SESL which is for SPI. For I2C you're only going to use the SESL (which will be called SCL) and MOSI (which will be called SDA)
    Another thing I've learned - fasten down your projects. It doesn't help when your boards keep moving around and dislodging wires. If you look at my pictures, 1 rubber band makes the world of difference. But of course, don't rubber band something that is gonna break!

And that's pretty much all there is to getting this board to work, at least for me. But I'm pretty sure almost anyone can do this, cause I've never really soldered anything before so if I can figure it out I have confidence you can too!
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Re: PN532 not working

by adafruit_support_bill on Tue Oct 29, 2013 6:01 pm

That's good to hear. :) All it takes is one loose breadboard jumper or a dodgy solder joint to cause headaches. And a multimeter is not always a reliable way to verify connectivity (many intermittent joints work just fine when you poke them with a probe).
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