topic Re: Fastest encoder IC in NFC

Fastest encoder IC

fernandohcoelho — Tue, 13 Dec 2016 12:22:54 GMT

Hi everyone,

I'm working with a arduino NFC shield, with a NXP RC522 chip. With my program, I'm getting this timming:

Discover tag: 25ms

Write mem sector: 10ms

Halt tag: 25ms

The question: Can I bring this values down with another NXP IC? Or this values are a technology limitation?

If I can do it faster, which IC must I use?

Thanks!!!

Fernando Coelho

Re: Fastest encoder IC

weidong_sun — Wed, 14 Dec 2016 07:25:31 GMT

Hello Fernando,

The speed is not releated to reader IC, it is determined by 4 factors:

(1) Interface type between CPU and Reader IC

For example, SPI is faster than UART and I2C.

(2) Speed of RF channel

(3) Handling speed of software

(4) Reflection speed of tag

regards,

weidong

Re: Fastest encoder IC

fernandohcoelho — Wed, 14 Dec 2016 11:09:09 GMT

weidong.sun‌, how you doing?!

Yeah, you are right. But the aspects you mentioned are not about the IC only. I think the IC have a lot of operations been done before send the response to a SPI port, for example.

I wanna know if a PN532 IC is faster than a RC522, for example, handling all this operations.

Thanks in advance!

Re: Fastest encoder IC

weidong_sun — Thu, 15 Dec 2016 07:00:47 GMT

Hello Fernando ,

I confirmed quesiton on the speed of PN532 & RC522 with NFC technical team, we can't say whose speed is faster, speed is determined by transaction & CPU handling time, not RF firmware( firmware in reader IC ).

Hope above information can help you!

Best Regards,

Weidong

Re: Fastest encoder IC

christianeisend — Thu, 15 Dec 2016 07:22:03 GMT

Hi,

speed is not directly determined by the used RF frontend but rather by the overall system partitioning. If you compare both devices, RC522 and PN532 there is one big difference: RC522 is a hard-wired logic, register based frontend. All hardware and protocol abstraction logic has to be implemented on your microcontroller.

PN532, on the other hand, is an integrated NFC controller so hardware and protocol abstraction runs diectly inside PN532 and is tightly coupled with the contactless interface. On host micrcontroller side only a few commands have to be sent in order to activate/detect a tag for instance whilst RC522 requires multiple low level register operations, each operation results in a single SPI/I2C transfer. PN532 performs this low level register operations directly onchip (inside PN532), so one register operations takes not even 1us. Writing a register from a host microcontroller into RC522 can take several hundred microseconds (counting software overhead, SPI/I2C transfer times etc.)

So looking at these facts I would say from overall system perspective PN532 could operate much faster than RC522.

Advantage of RC522 of course is a higher flexibility, since host micrcontroller has direct register access to the contatless interface hardware.

HTH,

Christian.

Re: Fastest encoder IC

fernandohcoelho — Thu, 15 Dec 2016 12:56:32 GMT

Hi Christian!

Thanks for the answer. Now the difference between the two IC become clear.

I'll buy a PN532 Arduino Shield and run some tests.

Thanks again!

Fernando Coelho