Need NFC Suggestion. Chip Emulation with ~1KB ram - Page 1
Forum section: electronics / projects

author: rfleming
author_rank: Regular Contributor
timestamp: March 02, 2021, 02:00:50 am
content: Hi All,I have been playing around with these for a bit now and I have been trying to find an IC that I could use for on-going read/write operations of the NFC. The device requires to be ran in NFC ISO14443 A or B mode as an emulated tag so a mobile or similar could read it. Though also needs to be capable of holding roughly 1Kb or greater.Since I plan to read/write from the chip up to 100 times a day and needs to work for a few yeas, EEPROM won't work as an option. So the ST chipsets wont fit the billI went through all the possible ICs on DigiKey and the only 2 I found were both from TI. The first (RF430CL330H) was spec'd perfectly, though turns out iOS doesn't support it, I found that out after physically testing it and found a discussion on the forums that mentioned the same thing. The second was a full transciever (TRF7960). I played around quite a bit with this one. When Chip Emulation ISO14443A is enabled, Android and iOS are unable to read it, though seems to work with ISO14443B. Since it is a transceiver though, it has a huge processing requirement and the micro we chose that we have already invested in for this project running on FreeRTOS cannot keep with up with latency requirements. Even the example devkits: LaunchPad+TRF7960A Dev board + external antenna had very poor connection and would take often minutes at a time to find the correct position for a mobile to initiate a data exchange - Android, even worse for an iPhone 10. Regardless, this solution would require a Co-Processor to run the transceiver...seemed a bit overkill and a rabbit hole that would take weeks to get right.Finally I came accross the NTAG series from NXP, their NT3H2211 should've been the perfect IC, though only has 64Bytes of sram. Despite having a higher eeprom write endurance of 500k, it wont fit our application. Finally NXP has a Smart Sensor series (Smart Sensorhttps://www.nxp.com/products/rfid-nfc/nfc-hf/ntag-smartsensor:NTAG-SMART-SENSOR) that appears to be the only chip available anywhere that has the capability to do what I am after. I originally rejected this IC series because DigiKey advertised them as a Reader/Writer, not a transponder.My question is, based on the requirements (before my bit spiel) could anyone suggest a more appropriate IC while confirming or rejecting what I have mentioned about the NTAG Smart Sensor series that it could be a viable option?

author: girishv
author_rank: Regular Contributor
timestamp: March 02, 2021, 04:06:23 am
content: Quote from: rfleming on March 02, 2021, 02:00:50 amCheckout ST M24SR series of products. They provide Type 4 tag emulation.https://www.st.com/en/nfc/m24sr-series-dynamic-nfc-tags.htmlThey support "NFC forum tag type 4". Probably they meet your requirements.

author: rfleming
author_rank: Regular Contributor
timestamp: March 02, 2021, 07:16:59 am
content: This series is unfortunately eeprom based, so I will elapsed the limit too quickly based on expected use of product.Based on the specifications we (sorry I mis-typed them) requires me to write to the NFC device to be ready for a read every 5seconds on-going. This would mean ~6mill writes/year if used continuously.

author: girishv
author_rank: Regular Contributor
timestamp: March 03, 2021, 01:53:52 am
content: Quote from: rfleming on March 02, 2021, 07:16:59 amYou can consider using PN512 NFC Front End which supports Type 4 Tag card emulation according to NFC Forum Type 4 Tag specification.https://www.nxp.com/products/rfid-nfc/nfc-hf/nfc-readers/standard-nfc-frontend:PN512Here is an example of card emulation.https://www.nxp.com/downloads/en/software-support/SW282911.zip

author: rfleming
author_rank: Regular Contributor
timestamp: March 03, 2021, 04:26:17 am
content: I have just been reading up on this exact one. I do find the NXP offering of the PNxxxx series of parts quite confusing to find the differences between them.I believe based on same very rudementary reading that the PN5180 is the next evolution of this series, though wasn't a big fan of the BGA package.I am still trying to find my feet with NFC, correct me if I am wrong, but does the IC only have 64 bytes of fifo memory, so if I had a 1kb payload, I would be sending it "live" from my main MCU -> PN512 -> Reader?Finally, would I require the S2C external IC to utilise this example?

author: girishv
author_rank: Regular Contributor
timestamp: March 03, 2021, 12:56:09 pm
content: Quote from: rfleming on March 03, 2021, 04:26:17 amYou should be able to send the payload from MCU.Quote from: rfleming on March 03, 2021, 04:26:17 amYou can integrate PN512 frontend with your main MCU. The example code is based on a PN512 reference board with LPCXpresso MCU.Further, checkouthttps://www.nxp.com/products/rfid-nfc/nfc-hf/nfc-readers/explore-nfc-exclusive-from-element14:PNEV512R

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 03, 2021, 06:32:45 pm
content: I can highly recommend AMS for this, for instance the AS3953:https://ams.com/AS3953

author: rfleming
author_rank: Regular Contributor
timestamp: March 03, 2021, 10:26:59 pm
content: I looked through the AMS catalogue, though all 4 options (on their website) are Discontinued or Last Time to Buy. Are they still making these? We want to be able to use the same IC for a few years.Also reading into the datasheet for your example it did look promising though also used EEPROM as its memory source for data exchange.

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 03, 2021, 10:44:23 pm
content: Quote from: rfleming on March 03, 2021, 10:26:59 pmWell, you're right.It's still in stock but I don't know what's their intention. I've used the AS3953 a few years ago. Last year, I noticed the status of those chips began to change on their website. Several times. This is odd. Contacting them may help understand the situation.If they really discontinue those devices, it's too bad really. I liked the AS3953 a lot. On top of implementing standard tags, you could use it as a general-purpose NFC data link along with some MCU and it supported up to 848 kb/s too (which I think no other similar product does.) It also was able to generate a power supply just from NFC energy so you could power your (low-power) MCU without any battery.Quote from: rfleming on March 03, 2021, 10:26:59 pmWell, either EEPROM, or as I said, you can use it for absolutely arbitrary data exchange, but in this case, you need to associate it with a MCU. Data interface is SPI. Any small MCU would do really.I haven't looked lately, but last year (or so) I noticed some of their NFC parts (the reader ICs) were handed off to ST Microelectronics. So maybe they are also going to do the same for their NFC tag ICs. have a look there.

author: harerod
author_rank: Frequent Contributor
timestamp: March 04, 2021, 06:22:20 pm
content: Quote from: rfleming on March 02, 2021, 03:00:50 am

author: rfleming
author_rank: Regular Contributor
timestamp: March 04, 2021, 10:42:36 pm
content: The highest endurance I have seen so far for the eeprom is 1million. Though I mistyped the specs. It requires to be written to whenever a reader comes in proximity or store on the device ready for when a reader is presented. The updates can be in intervals as low as 5 seconds, so it has a possible 6.3 million writes/year. Its intended to be an actual product, not so much a testing productI think it comes down to my lack of nfc knowledge of the ICs. I have specifically been looking through ICs and rejecting those that could not hold a 1kb sram frame internally instead of looking into a "pass through" option.

author: harerod
author_rank: Frequent Contributor
timestamp: March 05, 2021, 06:57:53 am
content: Ah, sorry, I got the "emulated tag" part wrong.Looking at your requirements, you might need something with wear leveling in the cells. Last time I dabbled in this stuff (ancient MyFare), I added a small MCU to the transponder driver. Depending on your estimated volume and seize requirements, you might want to contact some manufacturers directly.

author: Gribo
author_rank: Frequent Contributor
timestamp: March 05, 2021, 01:47:42 pm
content: TI has the RF430 parts which use FRAM.https://www.ti.com/lit/ds/symlink/rf430frl152h.pdf?ts=1614942656599&ref_url=https%253A%252F%252Fwww.ti.com%252Fwireless-connectivity%252Fother-wireless-technologies%252Fproducts.html%253FkeyMatch%253DNFC%2526tisearch%253DSearch-EN-everything