Dual interface memory (RFID/I2C)

Sorry I didn't specified, but I'm looking for a passive tag. I read the RF130CL330H datasheet and it say you only have active dual interface tag.

I'll find something else. Thank you for the answer J.D  ;)

Hey Clem,

Clem22 said:

Sorry I didn't specified, but I'm looking for a passive tag. I read the RF130CL330H datasheet and it say you only have active dual interface tag.

I couldn't find this in the datasheet, but the RF430CL330H is by NFC definition a "Passive Tag".  It's an ISO14443B Compliant NFC Type 4 Tag.  What defines a tag or reader as passive or active is if it has the ablility to generate an RF field.  The RF430CL330H cannot generate it's own RF field, so therefor it is a passive tag.  The Reader, lets say a cell phone for example, can tell no difference between RF430CL330H and an other passive tag.   

The real difference between RF430 and a standard ISO14443B tag, and what makes RF430CL330H "Dynamic", is the fact that RF430 has the I2C back side connecting it to a host MCU.  This can enable things like bi-directional communication between you application and a NFC enabled phone for example.  Because the RF430CL330H does have SRAM, it will still need to be powered from the application side to retain it's memory. 

We will also be releasing a wake-up circuit along with it which would allow the RF430 to be turned off.  Once a RF field is detected, the host would have to power and initialize the RF430 and then the Reader could talk with it.

Let me know if you have any questions about this.  RF430CL330H should have it's full datasheet released to the web and have EVM's available next week. 

I hope this is helpful.

Thanks,

JD      

Yes sorry, I misread the datasheet.

I forgot to mention I'm looking for a non volatile memory, so the SRAM is going to be a problem.

I found the TMS37157 but unfortunately it's a LF tag.

Alright Clem22,

Just wanted to clear that up.  Hopefully when we come out with the FRAM version of the RF430CL330H, that will fit your needs.  It should be coming out later this year, and FRAM is non-volitile.

Good luck!

JD

Hi JD,

     I'd like to know the security issue of  RF430CL330H, does RF430 embed with any password verification or data encryption protection? If I want to keep the specific user information in the memory sector, can it be duplicated or copy thru I2C bus directly? Any protected memory sector that could keep the confidential data in it?

Scott

Hey Scott,

There are no security/encryption features on RF430CL330H like what you are interested in.  Yes, If someone had access to the I2C lines, then they could read out RF430's memory contents.  But if they have a NFC enabled cell phone they could do the same.

In Type B NFC spec there isn't any password/encryption support, so as long as a reader sends NFC compliant commands, they are going to read the entire memory sector as well.  Now, you can fill the NDEF Message with encrypted data if you like, and have your reader need to have the key to decrypt it.

NFC is "intrinsically safe" because you have to get close enough to almost physically touch the tag.  Let me know if you have any more questions.

Thanks,

JD      

Hi JD,

      Thanks for your reply. Can you further explain ....." you can fill the NDEF Message with encrypted data if you like, and have your reader need to have the key to decrypt it."

If someone duplicates the entire memory contents including the encrypted data in NDEF Message thru I2C or RF interface by a NFC/RFID compliant reader and  then makes a same tag, the new copy tag can then pass the verification by my reader,right? If yes, is there a way to prevent it? How to protect my tag to be copy by any anyone else?

Scott 

Hey Scott,

You are correct about someone being able to clone the NDEF Message.  RF430CL300H isn't really designed for Access Control type solutions, which sounds like what you are looking for.  Writing Pre-Encrypted data into the NDEF message would allow only readers that knew your key to decrypt the message, but there is no way for the reader to tell between 2 different RF430's with the same NDEF message (except for the PUPI, but it is randomly selected at each power-up of the RF430).

For what you are wanting to do it might make since to look at passive tags that have built in encryption engines such as Mifare DESFIRE EV1 cards.  

With RF430 there is no way to prevent the data memory from being read through I2C or over the air when RF is on.

Thanks,

JD 

Hi JD,

Please let me confirm your answer as below.

> We will also be releasing a wake-up circuit along with it which would allow the RF430 to be turned off.  Once a RF field is detected, the host would have to power and initialize the RF430 and then the Reader could talk with it.

How is the host detected the RF field? And are you releasing this circuit?

Best regards,

Kaka

Hi Kaka,

An external transistor switch circuit is used to provide an interrupt signal from the RF430CL330H Vcore pin when a field is detected.  Please see the attached brief overview slides.  The circuit is actually layed out on the RF430CL330HTB, but not populated.  This is being documented and will be released as an application note. 

Also, here is the example code for the RF430CL330HTB + MSP-EXP430FR5739 boards as shown in the presentation.  Let me know if you have questions.

Hi Eddie,

Thank you for your response.

Also I would like to know whether you can provide the circuit in case of using the RF430CL330H as passive tag.

i.e. Can you provide the circuit which the RF430CL300H + MSP430 will completely work with field powered? (Rectify the RF signal on the antenna, and use it to power the circuit. )

If you have any questions, please let me know.

Best regards.

Kaka

Kaka,

It is possible to operate purely passive.  See the attached document.  It is important to note that the phone/tablet transceivers do differ in field strength and the length of the RF "field on" time during the polling cycle.  The performance of the passive operation with phones will vary.  If you have control of the reader, this is predictable.

Eddile,

Thank you for providing that documents. I will use this document if customer requests to use the RF430CL330H as passive tag.

Best regards.

Kaka

Is there any update on the new RF430CL330H part that uses non volatile FRAM as opposed to SRAM?

I believe that you are referring to RF430FRL152H.  That part is expected to be available late Q4 of this year.

There is a preview webpage available at this link:

http://www.ti.com/product/RF430FRL152H/description#features