TRF7970 and MIFARE

user4696470

Other Parts Discussed in Thread: TRF7970A

According to the document, to be compatible with MIFARE, I need to use Direct Mode Special, When in Special Direct Mode the TRF7970A sends a data clock to the MCU on I/O_5 (pin 22) and the Microcontroller controls the TRF7970A through I/O_2 (TX enable) and I/O_3 (data).

MY questions ：

1.When in Special Direct Mode ，Whether to identify other tags？

2.How to identify Mifare tags, automatic identification, or need to manually set up a special direct mode ？

3.It is compatible with Mifare in TRF7970A, the hardware design also need to pay attention to what the problem ?

over 7 years ago

0 Josh Wyatt over 7 years ago

TI__Guru* 90906 points

you would only use SDM after you have activated and selected the tag using ISO14443-2 Type A commands. You will know which type of tag it it by that point.

so, while you are using SDM, you would not be interacting with another card or looking for one, either. (this is no different from doing specific operations on any other tag, after branching off from activation polling cycle.

The ATQA will tell you what type it is, as will the SAK response.

see table 5 & 6 here ==>

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Thank you for your answer.

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Dear Josh，

Excuse me,

1.NFC antenna is required to take additional antenna or do the PCB printed board above?

2.What is the size of the antenna?

3.How much space should be reserved for the antenna periphery can not have metal?

4.The NFC position we have set aside on the device is only 25mm wide，Is the antenna capable of being put down?

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

you mean an antenna coil like this? (this is 25mm outer diameter, 3 turns on each side, 1mm trace width, with 0.5mm between traces

what sort of read range do you expect with that? which kind of tag are you using and what size is it?

any metal should be at least 5mm away or more if possible.

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Dear Josh，
I would like to know the minimum size of the antenna outside diameter can be done？If the metal is 5mm, our antenna size may be smaller.
Our reader needs to support reading the 4 basic NFC Tags 。

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

i would recommend making the antenna coil larger then. since you say you want to support all four tag platforms, this also means you can expect any size or shape to be presented as well. how much more room could you spare? unless you have a specific form factor to target a coupling factor for, then you really need to play it conservatively if you want your user experience to be any good.

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Because of the structure of the restrictions, the area of the antenna as I give you the picture above shows the area ，The width of the antenna is estimated to be only 20mm but the length can be done 80mm。

Antenna dimensions have rounded rectangular antenna？As follows ：

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

what about the perimeter of the PCB?

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Dear Josh，
You mean the perimeter of the antenna printed circuit board？
Our structure allows the space perimeter to be（20+80）x2=200mm

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Dear Josh,
Do you have any better suggestions ?
Looking forward to your reply, thank you.

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

can you send your dimensions again - what you sent must have been some mistake

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Dear Josh，

The size of the attached image is the maximum size that is reserved for the antenna plate on the display.

I mainly want to ask what kind of antenna we should use to meet the design and customer needs.

We need to support reading 4 types of basic NFC Tags

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

well - the forum themselves have published reference antenna sizes for interoperability
in your case, maybe coil size for poller # 6 or poller # 3 sizes would serve you (slide 8)

www.slideshare.net/.../nfc-forum-compliance-program-overview

0 user4696470 over 7 years ago in reply to Josh Wyatt

Prodigy 100 points

Sorry ，the web page can not open。

0 Josh Wyatt over 7 years ago in reply to user4696470

TI__Guru* 90906 points

please try again - it opens fine on my side - maybe you could also copy URL and paste into another browser window.

Other wireless

Other wireless technologies forum

TRF7970 and MIFARE