ST25 NFC/RFID tags and readers

I’m designing a tag coil for the ST25DV-04k. I am planning to use the ST25 to harvest NFC energy from a phone tap for a bioimpedance sensor (MAX30002). The ST25DV will then relay the sensor measurement to the phone via NFC again. I used an online calculator to design the tag coil, and these were the parameters I chose. Parameters for tag coilHowever, I am unsure if my quality factor is too high. “59.77” is before coupling, and I assume it will be lower after that. I understand that a high Q is great for energy harvesting, but it can limit the bandwidth and garble communication between the tag and the reader.Is my Q too high right now? If so, what is the optimal Q factor range? Anything else that stands out from my coil design?

Hello,I am using the ST25R200 evaluation board with the STSW-ST25R020 firmware package.I am planning to develop a custom Python GUI that displays a specific text string whenever an NFC tag is detected by the board. To achieve this, I want to modify the C firmware so it actively streams out a text string via UART/VCP as soon as a tag enters the field.Could you please guide me on the following?Which specific source file and function in the STSW-ST25R020 package handle the successful tag detection/inventory loop where the tag's UID is retrieved? Where is the best place to insert a custom printf or logging function to stream this text data out via UART immediately upon detection? Thank you very much for your help!

Hi, Could you please confirm whether an external NFC antenna can be connected to the X-NUCLEO-NFC08A1 board? I see P200 and P202 in the schematic, but it is not clear to me whether these are intended for external antenna connection or only for optional/test points. If an external antenna can be used, could you explain how the on-board etched PCB antenna should be disconnected from the ST25R3916B antenna path, where the external antenna should be connected instead, and what antenna inductance or electrical parameters should be targeted before tuning the matching network?Thanks!Best regards, Jose 

Hello, I have a STM32F401RCT connected to a ST25R100.In the ioc file I enabled the X-CUBE-NFC9 library with all the necesary dependencies.All the IOs also have pins assigned to them.Plus Pull ups enabled on the IRQ (open drain) and NFC_Reset.Currently I have found out that it crashes somewhere after MX_X_CUBE_NFC9_Init();ret code: 0NFC BSP COM = 100Welcome to X-NUCLEO-NFC09A1 entered error handlerThis is what I get in my console. I added some printfs in the code already.When I run it in debug mode to check were it calls the error handler it for some reason does not hit the error handler but it gets stuck in stm32F4xx_il_usb.c; when I click pauze, this seems rather odd.HAL_StatusTypeDef USB_FlushTxFifo(USB_OTG_GlobalTypeDef *USBx, uint32_t num){ __IO uint32_t count = 0U; /* Wait for AHB master IDLE state. */ do { count++; if (count > HAL_USB_TIMEOUT) { return HAL_TIMEOUT; } } while ((USBx->GRSTCTL & USB_OTG_GRSTCTL_AHBIDL) == 0U); /* Flush TX Fifo

Hello Team,I am facing RF read and write issues with the M24LR16E‑R EEPROM.The exact problem is as follows:When I take a new EEPROM and write data to it using an RF NFC reader for the first time, the operation is successful. However, during subsequent attempts to read and write: In some EEPROMs, RF read works but write fails but I2C read/Write working. In some devices, both read and write operations fail but I2C read/Write working. A few EEPROMs work correctly without any issues. In our application, we are using Sector 2 and Sector 3 for user data storage.When I read data from the problematic EEPROMs through St25 mobile application, I observe the following:Sector 0 and Sector 1 Security Status is 0x00. And the data read and write is working in these 2 sectors. Sector 2 to Sector 15 Security status: Current Security Status: 0x09 New Security Status: 0x09 Additionally, I receive the warning:“Sector locked. Security Status can only be changed through I2C.”I am not sure why the security

Hi,I am evaluating the ST25R200 using the ST25R200 Eval GUI. In Reader Mode, there is a Field Measurement tab that displays a numerical value together with a circular indicator. However, the displayed value does not appear to have any unit.Could you please clarify:What exactly is being measured in this tab? Does the value correspond to a physical quantity (e.g., magnetic field strength, ADC count, RSSI, amplitude, etc.)? Is there a conversion from the displayed value to a standard unit (A/m, µT, V, etc.)? Which ST25R200 registers or measurement circuitry are used to obtain this value? Is this functionality available through the ST25R200 firmware/API so that it can be implemented in a custom application?Any explanation of the measurement principle and interpretation of the displayed value would be greatly appreciated.Thank you.

I am using the STEVAL-25R300KA board with ST25PC-NFC version 3.0.2 on a PC running Windows 11.The software opens for a few seconds and then closes automatically by itself. I have already tried the following steps:Reinstalled the softwareRestarted my PCInstalled both x64 and x86 versions of the Microsoft Visual C++ Redistributable packagesChecked the Windows Event Viewer / Journal logs for any related errorsUnfortunately, none of these steps resolved the issue, and no specific error was detected in the logs.Could you please let me know what I can do to fix this problem and use the software properly?Thank you for your support.

Hello everyone,Has anyone successfully used the "ST25R95 EMI FILTER CALCULATION.xlsm" spreadsheet?I'm currently trying to use it for tuning the matching network of an ST25R95 design, but it doesn't seem to work correctly on my side. As soon as I modify any parameter or use the reset function, all the graphs disappear and I can no longer obtain any meaningful results.At the moment, this tool would be very useful for optimizing the matching network, and without it I'm having some difficulties proceeding with the tuning process.Has anyone experienced the same issue? Is there a specific Excel version, macro setting, or workaround required to make the spreadsheet work properly?Any suggestions, advice, or alternative methods for tuning the matching network would be greatly appreciated.Thank you in advance for your help.Marco

Hi again,Since the new version of ST Community I can't find my previous post, so I'm creating a new topic to follow up on the old one. The replies from @AScha.3 and @Brian TIDAL on that thread helped me a lot before it disappeared.As I mentioned, I'm a beginner in this field. The full context is in my earlier post:I have just one more question. You mentioned that building an external antenna is easy, but is it really doable for a beginner? I'd like to know whether I can realistically do it myself if I buy the right equipment to measure inductance, or whether I need an expert to guide me.Also, in addition to AN6065, I found AN2866, which is more readable in my opinion and provides a step-by-step procedure. I don't understand everything yet, but I'll work through it.Thanks!

Hello,I start testing with the STEVAL-M25R16B Board and use this Time the self compiled Demo from ST to test it. All works find.Then i made an own PCB with Reader IC  and Antenna on it and connect it to your MCU /Display Board.The Board is connected to 3.3V, GND and the SPI / IRQ Lines. The Antenna on my PCB is very small, only 21x26mm. Inductance measured with Siglent VNA 770nH.( 0.5mm Track Width, 0.3mm Distance, 3 Turns) The from your Tools calculated Values and my final Values after tuning differ..My Result: L=270nH, Cemv 680pF, Cs 220pF, CTune 430pF, Rs 0.68R I tuned the Circuit using my VNA and get a Reading Distance of about 25mm for 14443 Keyfobs and Cardsand about 6cm for ISO15693 Card.This all works fine.  Smith Chart looks perfect.The Rx Voltage is about 1.5Vpp. The Voltage Divider Capacitors are 33p/120p.ST25RProblem: Tags are working but in Emulate Mode i got no Reaction. With the Original Antenna (66x66mm) all is fine.Need a little help

Hi STM teams , i have developed a custom NFC board using the STM32L476RCT6 and the ST25R3916B NFC reader, based on the reference design of STEVAL-D25R16B (https://www.st.com/resource/en/schematic_pack/steval-25r3916b-schematic.pdf). I am using an external sticker antenna (Manufacturer Part Number: V2089-013-A-01). Currently, the board detects only the STEVAL-SMARTAG2 NFC tag card (https://www.st.com/resource/en/schematic_pack/steval-smartag2-schematic.pdf), while other NFC cards are not being detected. However, when I connect the custom NFC board to the DK antenna, it successfully detects the STEVAL-SMARTAG2 card as well as all other NFC cards. so i think issue may be sticker antenna Could anyone suggest a suitable sticker antenna or recommend an alternative external antenna solution? I have attached pictures of the sticker antenna, the STEVAL-SMARTAG2 card, and the other NFC tags for reference.

Hi everyone! I'm working with the NFC07A1 board associated with the Nucleo L053R8, with the intention of being able to perform ADC readings. I configured everything(ADC, pin, NFC07A1, etc.) on CubeMx, and then, opened the generated file on CubeIde. After writing the code for reading the ADC in the main file, i tried to run it, but even though there were no errors in the code, the  "startup_stm32l053r8tx.s" tab opens by pointing to line 51 (as well as Reset_Handler: ldr r0, =_estack). Consequently, the values acquired via the ADC are not printed on the screen, but the only thing printed on the sreen is "welcome to x-cube-nfc7 example". Could you help me solve the problem?

Hello There,I am currently trying to use the ST25R200 with the X-CUBE-NFC10 Software package.First thing am not sure about: In the "Software Packs Component Selector" I have to configure the "Board Extension NFC/NFC10A1" even when i don't plan to use this board. Otherwise i get a warning that "NFC10Boardlface" requires "NFC/NFC10A1". If I don't select the board part, I get a simmilar warning from the RFAL component.If i either don't add NFC/NFC10A1 in the component selector or don't select "Board Part NFC10Boardlface" in the Mode selection for the X-CUBE-NFC10 package, CubeMX seems to have problems generating the header "nfc_conf.h", which i have attached to this post.This is how the configuration looks, which generated nfc_conf.h:Am I using this library not correctly? Or rather which components of this library am i supposed to configure if i want to use the library with a custom board based on the ST25R200?Best Regards, Cecil

Hi,I have derived this code from the ST25NFCLib, and the software works correctly when interfacing with the NUCLEO-L476RG board.However, when I connect the same setup to my proto board, I observe a difference during the following I2C transaction.During the initialization process, the master sends command 0xDF (Measure Power Supply) and then waits for the IRQ signal.In the working setup, the IRQ status registers (1Ah–1Dh) return the values:00, 80, 00, 00Whereas in the non-working setup, the IRQ status registers return:00, 00, 00, 00I am not sure why the IRQ response is different in the proto board setup.Please note the following:Both the working and non-working setups use the same ST25R3918 daughter board.Both setups use the same interface signals: 3.3V, GND, IRQ, SCL, and SDA.The I2C communication speed is identical on both setups.I am attaching the I2C transaction screenshots for reference:The upper transaction belongs to the non-working setup.The lower transaction belongs to the work

Hello ST TeamI am using the ST25R3911B-DISCO board with an ST25DV16KC tag.I am trying to communicate with the tag directly from Python using the ST25R3911DISCOComm.dll from STSW-ST25R001.My setup is:ST25R3911B-DISCOST25DV16KCWindows PCPython 3.13ctypesThe DLL loads successfully.Reader connection works correctly.RF initialization works correctly.These APIs return success:rfalInitializeiso14443aInitrfalFieldOnAndStarGTcheckConnectionThe ST GUI software works correctly and can:detect the tagselect the tagread UIDread tag dataFrom Python I cannot:detect the tagselect the tagread UIDread memoryThe DLL exports these APIs:iso14443aSelectiso14443aRATSiso14443aPPStxrxBytesnfcTxNBytesnfcRxNBytesrfalStartTransceiverfalTransceiveBlockingTxrfalTransceiveBlockingRxrfalTransceiveBlockingTxRxrfalISO14443ATransceiveShortFramerfalISO14443ATransceiveAnticollisionFramerfalIsoDepInitializerfalIsoDepStartApduTransceivepollInterruptObserved issues:iso14443aSelect causes access violation.t2tRead4Pages returns

Hello,   I'm updating an ST25R3916B project to use the ST25R300 due to the obsolescence of the Murata variable capacitor. This project is read/write of ISO15693 tags only, no card emulation or anything fancy. It uses one IC which is then multiplexed with relays to 20 different antennae, each about 2cm square. The tag that we're reading is about 2cm by 1cm, and has been working reliably. So for this update I start by finding all the reference designs, and I saw this little gem, the STEVAL-ALOCKCB. It looks like it has an antenna the same size - how do I get more information about it? Can you please post the dimensions, or even better just send me the Altium files and I can get it out of there cleanly. Reference designator on there is ANT700.Also one question on that design - on PDF page 8 of the schematic it has the filter and antenna match but it looks like it's duplicated on both sides of the connector - why? Is that in case someone wants to use a different antenna at t

Hello,I am a French engineering student working on a startup project as part of my MBA. We are developing an interactive musical box for children aged 3 to 7 years old.The core feature of the product relies on RFID detection: small figurines shaped like musical instruments are placed on a circular rotating tray (15 cm diameter). Each figurine has an RFID tag under its base. When a figurine is placed on the tray, the reader must detect it and trigger the corresponding audio track.Here are our technical constraints:- The reader will be fixed under the tray, at a very short vertical distance (1 to 2 cm at most)- The detection zone must cover the full surface of the tray, meaning a lateral radius of 7.5 cm- The tags will be in slow rotational movement- The reader must be connectable to a PC via USB for prototyping purposes, so we can retrieve detected tag UIDs in real time via a Python or JavaScript script- Budget constraint: under 100€After research, we identified the ST25R3911B-DISCO eva

I want to try the multi antena design mentioned in AN6121. where can I either download the gerber files for the PCB or order a PCB?

Dear ST colleagues,I tried recently the package X-CUBE-NFC12.First I tested on NUCLEO-L476RG board the delivered example and it was working out of the box, then I tried on NUCLEO-C071RB but it was not working, first I noticed that the Pins configuration are not correct it was fixed, but still not working, did anyone ever test this example, because I assume it needs to work without any modification.Thank you in advance for your support.Best regardsBassem Taamallah

I am currently working with the X-NUCLEO-NFC10A1 board and interfacing it with an ESP32 DevKit V1. While attempting to establish communication between the two, I have tried all SPI modes as well as different reset logic configurations, but I am still unable to get them to communicate properly.I have included my Arduino test code below for reference, which I am using to verify the communication:Please check in attachment section there is code file

Hi all! I'm trying to implement a wear leveling in user memory accessed from I2C for a counter on bit level. My question is: Are ST25DV eeprom byte cells similar to classic ones where each write cycle starts with a clear (which sets the byte to 0xFF) and after it writes 0 bits where needed? Or is there somewhere an inversion taking place? Could someone help me, by pointing out some directions in datasheets for me in this matter? I found another post where memory default state is quoted from the datasheet which specifies that factory default is 0x00, but this doesn't imply that it's default state isn't 0xFF. Thanks in advance, notram

I have been using RFAL succesfully with STM32L4. For a more price sensitive project I need to port the code to STMG070 and I cannot get RFID readings to work. Measuring ampltiude gives same result on both codes:st25r3911MeasureAmplitude(&c); printf("Amplitude %d\n\r", c); The following have been verified:* Same RFID PCB is used for both processors (RFID PCB and processor PCB are connected by pin connector)* Same RFID card is used* Init of RFAL gives ID 13 on both codes* GPIO interrups are generated* Same LDO on both PCB* Voltage to ST25R3911B is stable* Both processors runs at same frequency 16 MHz On STM32L4 the state change (during a succesful RFID read) of rfalNfcWorker goes like:RFAL_NFC_STATE_IDLERFAL_NFC_STATE_POLL_TECHDETECT x 19RFAL_NFC_STATE_POLL_COLAVOIDANCE x 29RFAL_NFC_STATE_POLL_ACTIVATION x 2But when running on STM32G070 RFAL_NFC_STATE_IDLERFAL_NFC_STATE_POLL_TECHDETECTRFAL_NFC_STATE_LISTEN_TECHDETECT until timeout  Anyone have

Just a heads-up, this post was written by AI. I used it to document a process of debugging this board, and create a summary for a forum post.Platform: ST25R3911B, RFAL library, ISO 14443AConfig: Single-ended mode, 0.3m 50Ω coaxial cable, remote antenna PCBSupply: 5V on VDD and VIORead range: ~10mm (expected 40-80mm for antenna size)Setup OverviewI'm using an ST25R3911B driving a remote PCB antenna via a 0.3m 50Ω coaxial cable in single-ended mode (RFO1). The antenna is a 2-turn square loop, 70×70mm outer dimension, 1.4mm trace width, 0.7mm spacing, calculated inductance ~735nH.The chip drives two antennas switched alternately — RFO1 to the remote antenna via coax, RFO2 to a local antenna. Both antennas show identical poor range (~10mm), so the problem is not specific to the coax path.Hardware — Reader PCB Matching NetworkDesigned using the ST25R Antenna Matching Tool V3.6.2 with these parameters:Target: ST25R3911BConfig: single-ended-cableAntenna inductance: 701 nHTarget matching Z: 8

Hello, we have a working design that is in production, but obviously cannot keep building because of the EOL variable capacitors. Our application is reader only, no card emulation. Since we don't need CE, do the variable capacitors need to be populated? Or can they be replaced with a fixed value capacitor? If the latter is correct, then what value capacitor to use? We want to minimize changes to the design since it is working well. In the future we will change to the ST25R300 bur right now we have to stick with the current design. Thanks,Derek

Hi everyone,I’m currently working with the CR95HF and looking into using the provided DLL (CR95HF.dll) for PC-side communication.From the documentation and software packages I understand that a DLL is provided to interface with the CR95HF demonstration board (). However, it seems this DLL was originally built for older environments and is typically installed in x32 systems, which suggests it may be a 32-bit library.I searched the community and found a previous discussion where someone asked about x64 compatibility ( Solved: CR95HF DLL for x64 - STMicroelectronics Community ) and was provided with source code instead of a precompiled DLL.So my questions are:Is there now an official x64-compatible version of the CR95HF DLL available?Or is the recommended approach still to request/use the source code and rebuild the DLL for x64 systems?If rebuilding is required:Is there any official guidance or updated project for generating a 64-bit version?Thanks in advance for your help!