[Swansea Hackspace] RC522 RFID module from China...

[Justin Mitchell]

On Sat, 2014-10-25 at 21:06 +0100, Emyr Morris wrote:
> well, I mentioned a few weeks ago at 'the space' that I was waiting
> for one of those dead cheep RFID modules from China.

> http://playground.arduino.cc/Learning/MFRC522

> 
> 
> Concerns were voiced at 'the space' that the module is 3.3V
> 
> 
> Power must be sent to it from the Arduino 3.3V pin - and the consensus
> online is that the unit is 5V tolerant - so far mine has worked fine
> without using a level converting dooffer.

I had wondered this, as there are mixed reports of wether it was 5v
tolerant or not, looking up the datasheet for the NXP chip that is
definitely not 5v tolerant, the max input voltages for the input pins
are quite clearly below that (Vdd + 0.5V)

But there are rather a lot of resistors on the board, hard to tell
exactly what they are all for so it might be, but when the level
converter boards are so cheap i haven't risked it.