• Registered: 2011-05-08
  • Posts: 2

Topic: building my own board and looking for advice

I am very new to NFC, so please excuse my ignorance.

I have a fair bit of experience with hardware like custom FPGAs, and uC boards. So I would like some advice on picking a chip for custom NFC board for various 13.56 MHz applications. I would defiantly want this board to be able to use PayPass type tags for actual financial transactions, but I would also like to use it for other types of access control cards.

The TS-7500 ARM SBC board that is part of my preexisting system that I want to integrate NFC board into by mating the boards together via the 40pin header. It has hardware serial UARTs, SPI, I2C available. I am not interested in a chip with a USB only interface. I have a open-embedded based distro on the board so compiling libnfc shouldn't be an issue.

I was staying away from the PN532 since its being phased out, and the board I am making might need to be in active production for a while. So what is the difference in functionality between a PN512 "transmitter" (what NXP calls it) and a "controller" like the PN532/PN533?

Some open source schematics I have read use pins SIG_IN, SIG_OUT, SIG_CLK. What tags, protocols, and situations require the SAM? Is the sam usable without SSC hardware (like the kind onboard ATMel chips, I ask because I have seen references to timing issues when using GPIOs).

Thanks ahead of time for the help.

  • rconty
  • Administrator
  • Offline
  • Registered: 2009-04-22
  • Posts: 673

Re: building my own board and looking for advice

cargoudel wrote:

I was staying away from the PN532 since its being phased out, and the board I am making might need to be in active production for a while.

Are you sure that PN532 is being phased out ?
I know that PN531 is deprecated (and not sold anymore) but PN532 and PN533 seems to be (and stay) on market, am I wrong ?
BTW, PN544 (used in Google Nexus S) is a new NFC controller from NXP but I don't know if it will replace PN532 soon.

cargoudel wrote:

So what is the difference in functionality between a PN512 "transmitter" (what NXP calls it) and a "controller" like the PN532/PN533?

PN512 could be consider as a RFID/NFC (@13,56Mhz) modulator/demodulator. PN53x provides some convenient higher level commands.

cargoudel wrote:

Some open source schematics I have read use pins SIG_IN, SIG_OUT, SIG_CLK. What tags, protocols, and situations require the SAM? Is the sam usable without SSC hardware (like the kind onboard ATMel chips, I ask because I have seen references to timing issues when using GPIOs).

In NXP terms, SAM (Secure Access Module) is a "wired tag" connected to the PN532.
PN532 can use this SAM, 2 main ways:
* The host can "see" this tag and use it to do some secured tasks (ie. store some datas, sign using PKI -if presents)
* The PN532 can as act a wireless tag using the SAM, in this mode PN532 is an "antenna" for the SAM, thats the external initiator which talk with the SAM.

I hope it helps.

Romuald Conty
  • Registered: 2011-05-08
  • Posts: 2

Re: building my own board and looking for advice

From what I understand then, the PN512 is not usable for libnfc; since it doesn't have higher level commands/functionality built in.

The PN532 seems like best option for me, but the production will by the end of the year. At least according this this: http://www.nxp.com/pip/120112.html

Also, I have seen a lot of people talking about adding SPI or I2C support to libnfc and have seen some general work towards that end, but this work is incomplete correct? So this leaves me with UART interface, and the PN532 is the only NFC with that interface option with libnfc support, correct?

Regarding the SAM again I was reading this PDF
http://www.nxp.com/documents/leaflet/75016623.pdf
It mentions the connection being used to emulate a Paypass tag, but can you use a PN532 without a attached secure element, to read/make regular PayPass transitions?

  • rconty
  • Administrator
  • Offline
  • Registered: 2009-04-22
  • Posts: 673

Re: building my own board and looking for advice

cargoudel wrote:

From what I understand then, the PN512 is not usable for libnfc

You are right, libnfc doesn't currently support the PN512 but I think it should be possible to implement a driver from it.

cargoudel wrote:

The PN532 seems like best option for me, but the production will by the end of the year.

On the page you point, in "Discontinued information" section there are references from PN5320A3HN/C103 to PN5320A3HN/C105, but the currently sold PN532 is PN5320A3HN/C106, AFAIK.

cargoudel wrote:

Also, I have seen a lot of people talking about adding SPI or I2C support to libnfc and have seen some general work towards that end, but this work is incomplete correct?

Correct, but the job should not take to much time to be done.

cargoudel wrote:

So this leaves me with UART interface, and the PN532 is the only NFC with that interface option with libnfc support, correct?

Correct.

cargoudel wrote:

It mentions the connection being used to emulate a Paypass tag, but can you use a PN532 without a attached secure element, to read/make regular PayPass transitions?

I didn't experiment myself, but AFAIK to act as Paypass PICC (ie. emulate a Paypass tag), you have to use a Paypass compiliant secure element. To act as a Paypass PCD compiliant device (ie. talk to Paypass tag to made transaction), I think you have to fit the "Paypass - ISO/IEC 14443 Implementation Specification 1.1", please note that the PN533 does have some included routines to poll/release Paypass tags. Have a look to:
http://www.nxp.com/documents/user_manua … 080103.pdf

Romuald Conty
  • Registered: 2009-03-31
  • Posts: 12

Re: building my own board and looking for advice

cargoudel wrote:

So what is the difference in functionality between a PN512 "transmitter" (what NXP calls it) and a "controller" like the PN532/PN533?

According to the manual, the PN533 (didn't checked the PN532) could be switched via pins #20 and #21 into PN512 mode during the reset state, it's on the page 175. Nice feature I would say, but didn't tried it yet.

  • rconty
  • Administrator
  • Offline
  • Registered: 2009-04-22
  • Posts: 673

Re: building my own board and looking for advice

Hello,

ynezz wrote:

According to the manual, the PN533 (didn't checked the PN532) could be switched via pins #20 and #21 into PN512 mode during the reset state, it's on the page 175. Nice feature I would say, but didn't tried it yet.

You're right but please note that important information:

PN532 User manual (page 6/200) wrote:

The link used is RS232 at 9600 bauds. It is not possible to change the value of the baud rate; the SerialSpeedReg register is not emulated.

So, unfortunately the PN512 will be limited in UART connection speed, which can be a problem in some cases (ie. emulation).

Romuald Conty
  • Registered: 2010-12-21
  • Posts: 16

Re: building my own board and looking for advice

cargoudel wrote:

I was staying away from the PN532 since its being phased out, and the board I am making might need to be in active production for a while. So what is the difference in functionality between a PN512 "transmitter" (what NXP calls it) and a "controller" like the PN532/PN533?

That's news to me.  I don't believe NXP has any plans to discontinue this chip, and when I asked specifically about it compared to the PN544 they are both targetting seperate audiences.  The PN544 is optimised for mobiled phones, and the PN532 remains their intended chip for general-purpose MCUs, etc.  I think you can safely count on PN532 availability for the near future.  If you've heard differently this isn't the same message I got from NXP not long ago, but feel free to get in touch with them.