NT3H1101/NT3H General description. 2. Features and benefits. NTAG I 2 C, NFC Forum type 2 Tag compliant IC with I 2 C interface

Transcription

1 NTAG I 2 C, NFC Forum type 2 Tag compliant IC with I 2 C interface General description The NTAG I 2 C is the first product of NXP s NTAG family offering both contactless and contact interfaces (see Figure 1). In addition to the passive NFC Forum compliant contactless interface, the IC features an I 2 C contact interface, which can communicate with a microcontroller if the NTAG I 2 C is powered from an external power supply. An additional externally powered SRAM mapped into the memory allows a fast data transfer between the RF and I 2 C interfaces and vice versa, without the write cycle limitations of the EEPROM memory. The NTAG I 2 C product features a configurable Field Detection Pin, which provides a trigger to an external device depending on the activities at the RF interface. The NTAG I 2 C product can also supply power to external (low power) devices (e.g., a microcontroller) via the embedded energy harvesting circuitry. NFC enabled device EEPROM I 2 C Energy Harvesting Micro controller Data Field detection Data Energy Energy aaa Fig 1. Contactless and contact system 2. Features and benefits 2.1 Key features RF interface NFC forum Type 2 Tag compliant I 2 C interface

2 Configurable field detection pin based on open drain implementation that can be triggered upon the following events: A RF field presence The first Start-of-Frame The selection of the tag only 64 byte SRAM buffer for fast transfer of data (Pass-through mode) between the RF and the I 2 C interfaces located outside the User Memory Wake up signal at the field detect pin when: New data has arrived from one interface Data has been read by the receiving interface Clear arbitration between RF and I 2 C interfaces: First come, first serve strategy Status flag bits to signal if one interface is busy writing to or reading data from the EEPROM Energy harvesting functionality to power external devices (e.g. microcontroller) FAST READ command for faster data reading 2.2 RF interface Contactless transmission of data NFC Forum Type 2 tag compliant (see Ref. 1) Operating frequency of MHz Data transfer of 106 kbit/s 4 bytes (one page) written including all overhead in 4,8 ms via EEPROM or 0,8 ms via SRAM (Pass-through mode) Data integrity of 16-bit CRC, parity, bit coding, bit counting Operating distance of up to 100 mm (depending on various parameters, such as field strength and antenna geometry) True anticollision Unique 7 byte serial number (cascade level 2 according to ISO/IEC (see Ref. 2) 2.3 Memory 1904 bytes freely available with User Read/Write area (476 pages with 4 bytes per pages) for the NTAG I 2 C 2k version 888 bytes freely available with User Read/Write area (222 pages with 4 bytes per pages) for the NTAG I 2 C 1k version Field programmable RF read-only locking function with static and dynamic lock bits configurable from both I²C and NFC interfaces 64 bytes SRAM volatile memory without write endurance limitation Data retention time of 20 years Write endurance 200,000 cycles 2.4 I 2 C interface I 2 C slave interface supports Standard (100 khz) and Fast (up to 400 khz) mode (see Ref. 3) of 62

3 16 bytes (one block) written in 4,5ms (EEPROM) or 0,4 ms (SRAM - Pass-through mode) including all overhead RFID chip can be used as standard I 2 C EEPROM 2.5 Security Manufacturer-programmed 7-byte UID for each device Capability container with one time programmable bits Field programmable read-only locking function per page (per 32 pages for the extended memory section) 3. Applications 2.6 Key benefits The Pass-through mode allows fast download and upload of data from RF to I²C and vice versa without the cycling limitation of EEPROM NDEF message storage up to 1904 bytes (2k version) or up to 888 bytes (1k version) The mapping of the SRAM inside the User Memory buffer allows dynamic update of NDEF message content 4. Ordering information With all its integrated features and functions the NTAG I 2 C is the ideal solution to enable a contactless communication via an NFC device (e.g., NFC enabled mobile phone) to an electronic device for: Zero power configuration (late customization) Smart customer interaction (e.g., easier after sales service, such as firmware update) Advanced pairing (for e.g., WiFi or Blue tooth) for dynamic generation of sessions keys Easier product customization and customer experience for the following applications: Home automation Home appliances Consumer electronics Healthcare Printers Smart meters Table 1. Ordering information Type number Package Name Description Version NT3H1101W0FHK XQFN8 Plastic, extremely thin quad flat package; no leads; 8 terminals; body 1.6 x SOT x 0.6mm; 1k bytes memory, 50pF input capacitance NT3H1201W0FHK XQFN8 Plastic, extremely thin quad flat package; no leads; 8 terminals; body 1.6 x 1.6 x 0.6mm; 2k bytes memory, 50pF input capacitance SOT of 62

4 5. Marking Table 2. Marking codes Type number NT3H1201FHK NT3H1101FHK Marking code N12 N11 6. Block diagram VCC GND Vout POWER MANAGEMENT/ ENERGY HARVESTING I 2 C SLAVE LA DIGITAL CONTROL UNIT MEMORY SDA LB RF INTERFACE ARBITER/STATUS REGISTERS ANTICOLLISION I 2 C CONTROL EEPROM SCL COMMAND INTERPRETER MEMORY INTERFACE SRAM FD aaa Fig 2. Block diagram of 62

5 7. Pinning information 7.1 Pinning A LB LA VOUT A VSS 2 6 VCC SCL 3 5 SDA 4 FD Transparent top view B side view aaa (1) Dimension A: 1.6 mm (2) Dimension B: 0.5 mm Fig 3. Pin configuration 7.2 Pin description Table 3. Pin description Pin Symbol Description 1 LA Antenna connection LA 2 VSS GND 3 SCL Serial Clock I 2 C 4 FD Field detection 5 SDA Serial data I 2 C 6 VCC VCC in connection (external power supply) 7 V out Voltage out (energy harvesting) 8 LB Antenna connection LB NXP recommends leaving the central pad of the package unconnected of 62

6 8. Functional description 8.1 Block description NTAG I 2 C ICs consist of (see details below): 2016 bytes of EEPROM memory, 64 Bytes of SRAM, a RF interface, Digital Control Unit (DCU), Power Management Unit (PMU) and an I²C interface. Energy and data are transferred via an antenna consisting of a coil with a few turns, which is directly connected to NTAG I 2 C IC. No further external components are necessary. RF interface: modulator/demodulator rectifier clock regenerator Power-On Reset (POR) voltage regulator Anticollision: multiple cards may be selected and managed in sequence Command interpreter: processes memory access commands supported by the NTAG I 2 C EEPROM interface 8.2 RF interface The RF-interface is based on the ISO/IEC Type A standard. During operation, the NFC device generates an RF field. The RF field must always be present (with short pauses for data communication), as it is used for both communication and as power supply for the tag. For both directions of data communication, there is one start bit at the beginning of each frame. Each byte is transmitted with an odd parity bit at the end. The LSB of the byte with the lowest address of the selected block is transmitted first. The maximum length of an NFC device to tag frame is 163 bits (16 data bytes + 2 CRC bytes = start bit). The maximum length of a fixed size tag to NFC device frame is 307 bits (32 data bytes + 2 CRC bytes = start bit). The FAST_READ command has a variable frame length, which depends on the start and end address parameters. The maximum frame length supported by the NFC device must be taken into account when issuing this command. For a multi-byte parameter, the least significant byte is always transmitted first. For example, when reading from the memory using the READ command, byte 0 from the addressed block is transmitted first, followed by bytes 1 to byte 3 out of this block. The same sequence continues for the next block and all subsequent blocks Data integrity The following mechanisms are implemented in the contactless communication link between the NFC device and the NTAG I²C IC to ensure very reliable data transmission: 16 bits CRC per block of 62

7 Parity bits for each byte Bit count checking Bit coding to distinguish between 1, 0 and no information Channel monitoring (protocol sequence and bit stream analysis) The commands are initiated by the NFC device and controlled by the Digital Control Unit of the NTAG I 2 C IC. The command response depends on the state of the IC, and for memory operations, also on the access conditions valid for the corresponding page RF communication principle POR HALT IDLE WUPA REQA WUPA identification and selection procedure READY 1 ANTICOLLISION HLTA SELECT cascade level 1 READY 2 ANTICOLLISION SELECT cascade level 2 ACTIVE READ (16 Byte) FAST_READ WRITE SECTOR_SELECT GET_VERSION memory operations aaa Fig 4. RF communication principle of NTAG I 2 C The overall RF communication principle is summarized in Figure IDLE state After a power-on reset (POR), the NTAG I 2 C switches to the IDLE state. It only exits this state when a REQA or a WUPA command is received from the NFC device. Any other data received while in this state is interpreted as an error, and the NTAG I 2 C remains in the IDLE state of 62

8 After a correctly executed HLTA command e.g., out of the ACTIVE state, the default waiting state changes from the IDLE state to the HALT state. This state can then only be exited with a WUPA command READY 1 state In the READY 1 state, the NFC device resolves the first part of the UID (3 bytes) using the ANTICOLLISION or SELECT commands in cascade level 1. This state is correctly exited after execution of the following command: SELECT command from cascade level 1: the NFC device switches the NTAG I 2 C into READY2 state where the second part of the UID is resolved READY 2 state In the READY 2 state, the NTAG I 2 C supports the NFC device in resolving the second part of its UID (4 bytes) with the cascade level 2 ANTICOLLISION command. This state is usually exited using the cascade level 2 SELECT command. Remark: The response of the NTAG I 2 C to the cascade level 2 SELECT command is the Select AcKnowledge (SAK) byte. In accordance with ISO/IEC 14443, this byte indicates if the anticollision cascade procedure has finished. NTAG I 2 C is now uniquely selected and only this device will communicate with the NFC device even when other contactless devices are present in the NFC device field ACTIVE state All memory operations are operated in the ACTIVE state. The ACTIVE state is exited with the HLTA command and upon reception, the NTAG I 2 C transits to the HALT state. Any other data received when the device is in this state is interpreted as an error. Depending on its previous state, the NTAG I 2 C returns to either the IDLE state or HALT state HALT state HALT and IDLE states constitute the two wait states implemented in the NTAG I 2 C. An already processed NTAG I 2 C can be set into the HALT state using the HLTA command. In the anticollision phase, this state helps the NFC device distinguish between processed tags and tags yet to be selected. The NTAG I 2 C can only exit this state upon execution of the WUPA command. Any other data received when the device is in this state is interpreted as an error, and NTAG I 2 C state remains unchanged. 8.3 Memory organization The memory map is detailed in Figure 5 (1k memory) and Figure 6 (2k memory) from the RF interface and in Figure 7 (1k memory) and Figure 8 (2k memory) from the I 2 C interface. The SRAM memory is not mapped from the RF interface, because in the default settings of the NTAG I 2 C the Pass-through mode is not enabled. Please refer to Section 11 for examples of memory map from the RF interface with SRAM mapping. The structure of manufacturing data, static lock bytes, capability container and user memory pages (except of the user memory length) are compatible with other NTAG products of 62

9 Any memory access which starts at a valid address and extends into an invalid access region will return 0x00 value in the invalid region Memory map from RF interface Memory access from the RF interface is organized in pages of 4 bytes each. Sector adr. Page address Byte number within a page Access Hex. Dec. Hex conditions 0h 0 0h Serial number READ 1 1h Serial number Internal data READ 2 2h Internal data Lock bytes READ/R&W 3 3h Capability Container (CC) READ&WRITE 4 4h 15 0Fh User memory READ&WRITE 225 E1h 226 E2h Dynamic lock bytes 00h R&W/R 227 E3h 228 E4h 229 E5h 230 E6h 231 E7h 232 E8h 233 E9h Configuration See section EAh 255 FFh 1h 2h 3h 0 0h F8H F9H Session registers See section FFH aaa Fig 5. NTAG I²C 1k memory organization from the RF interface of 62

10 Sector adr. Page address Byte number within a page Access Hex. Dec. Hex conditions 0h 0 0h Serial number READ 1 1h Serial number Internal data READ 2 2h Internal data Lock bytes READ/R&W 3 3h Capability Container (CC) READ&WRITE 4 4h 15 0Fh 1h FFh 0h 1h DFh E0h E1h E2h E3h E4h E5h E6h E7h E8h E9h EAh FFh User memory Dynamic lock bytes 00h READ&WRITE R&W/R Configuration See section h 3h 0 0h F8H F9H Session registers See section FFH aaa Fig 6. NTAG I²C 2k memory organization from the RF interface Memory map from I²C interface The memory access of NTAG I²C from the I²C interface is organized in blocks of 16 bytes each of 62

11 Byte number within a block I 2 C block address Access conditions Dec. Hex h I 2 C addr.* Serial number R&W/READ Serial number Internal data READ Internal data Lock bytes READ/R&W Capability Container (CC) READ&WRITE 1 1h User memory READ&WRITE 55 37h 56 38h User memory READ&WRITE User memory READ&WRITE Dynamic lock bytes 00h R&W 00h 00h 00h 00h READ 57 39h 58 3Ah Configuration See section fixed 00h fixed 00h fixed 00h fixed 00h READ fixed 00h fixed 00h fixed 00h fixed 00h READ 59 3Bh 247 F7h 248 F8h SRAM memory (64 bytes) READ&WRITE 251 FBh 254 FEh Session registers (requires READ-Register command) See section fixed 00h fixed 00h fixed 00h fixed 00h READ fixed 00h fixed 00h fixed 00h fixed 00h READ aaa Fig 7. Remark: * The Byte 0 of Block 0 is always read as 04h. Writing to this byte modifies the I²C address. NTAG I²C 1k memory organization from the I²C interface of 62

12 Byte number within a block I 2 C block address Dec. Hex h I 2 C addr.* Serial number Serial number Internal data Internal data Lock bytes Capability Container (CC) 1 1h User memory h h Dynamic lock bytes 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h 00h h Access conditions R&W/READ READ READ/R&W READ&WRITE READ&WRITE R&W READ 122 7Ah Configuration See section fixed 00h fixed 00h fixed 00h fixed 00h READ fixed 00h fixed 00h fixed 00h fixed 00h READ 123 7Bh 247 F7h 248 F8h SRAM memory (64 bytes) READ&WRITE 251 FBh 254 FEh Session registers (requires READ-Register command) See section 8.9 fixed 00h fixed 00h fixed 00h fixed 00h READ fixed 00h fixed 00h fixed 00h fixed 00h READ aaa Fig 8. Remark: *The Byte 0 of Block 0 is always read as 04h. Writing to this byte modifies the I²C address. NTAG I²C 2k memory organization from the I²C interface EEPROM The EEPROM is a non volatile memory that stores the 7 byte UID, the memory lock conditions, IC configuration information and the 1904 bytes User Data (888 byte User Data in case of the NTAG I 2 C 1k version) SRAM For frequently changing data, a volatile memory of 64 bytes with unlimited endurance is built in. The 64 bytes are mapped in a similar way as is done in the EEPROM, i.e., 64 bytes are seen as 16 pages of 4 bytes of 62

13 The SRAM is only available if the tag is powered via the VCC pin. The SRAM is located at the end of the memory space and it is always directly accessible by the I 2 C host (addresses F8h to FBh). An RF reader cannot access the SRAM memory in normal mode (i.e., outside the Pass-through mode). The SRAM is only accessible by the RF reader if the SRAM is mirrored onto the EEPROM memory space. With Memory Mirror enabled (SRAM_MIRROR_ON_OFF=1 - see Section 11.2), the SRAM can be mirrored in the User Memory (page 1 to page see Section 11.2) for access from the RF side. The Memory mirror must be enabled once both interfaces are ON as this feature is disabled after each POR. The register SRAM_MIRROR_BLOCK (see Table 10) indicates the address of the first page of the SRAM buffer. In the case where the SRAM mirror is enabled and the READ command is addressing blocks where the SRAM mirror is located, the SRAM mirror byte values will be returned instead of the EEPROM byte values. Similarly, if the tag is not VCC powered, the SRAM mirror is disabled and reading out the bytes related to the SRAM mirror position would return the values from the EEPROM. In the Pass-through mode (PTHRU_ON_OFF=1 - see Section ), the SRAM is mirrored to the fixed address for RF access (see Section 11) in the first memory sector for NTAG I 2 C 1k and in the second memory sector for NTAG I 2 C 2k UID/serial number The unique 7-byte serial number (UID) is programmed into the first 7 bytes of memory covering page addresses 00h and 01h - see Figure 9. These bytes are programmed and write protected in the production test. SN0 holds the Manufacturer ID for NXP Semiconductors (04h) in accordance with ISO/IEC MSB LSB manufacturer ID for NXP Semiconductors (04h) byte page 0 UID0 UID1 UID2 UID3 page 1 page 2 UID4 UID5 UID6 SAK bytes UID ATQA0 ATQA1 lock bytes aaa Fig 9. UID/serial number Static lock bytes The bits of byte 2 and byte 3 of page 02h (via RF) or byte 10 and 11 address 0h (via I 2 C) represent the field programmable, read-only locking mechanism (see Figure 10). Each page from 03h (CC) to 0Fh can be individually locked by setting the corresponding locking bit Lx to logic 1 to prevent further write access. After locking, the corresponding page becomes read-only memory of 62

14 The three least significant bits of lock byte 0 are the block-locking bits. Bit 2 controls pages 0Ah to 0Fh (via RF), bit 1 controls pages 04h to 09h (via RF) and bit 0 controls page 03h (CC). Once the block-locking bits are set, the locking configuration for the corresponding memory area is frozen. MSB L 7 L 6 L 5 L 4 L CC BL BL 9-4 LSB BL CC MSB L 15 L 14 L 13 L 12 L 11 L 10 L 9 LSB L 8 page lock byte 0 lock byte 1 Lx locks page x to read-only BLx blocks further locking for the memory area x aaa Fig 10. Static lock bytes 0 and 1 For example, if BL15-10 is set to logic 1, then bits L15 to L10 (lock byte 1, bit[7:2]) can no longer be changed. The static locking and block-locking bits are set by the bytes 2 and 3 of the WRITE command to page 02h. The contents of the lock bytes are bit-wise OR ed and the result then becomes the new content of the lock bytes. This process is irreversible from RF perspective. If a bit is set to logic 1, it cannot be changed back to logic 0. From I²C perspective, the bits can be reset to 0. The contents of bytes 0 and 1 of page 02h are unaffected by the corresponding data bytes of the WRITE. The default value of the static lock bytes is 00 00h Dynamic Lock Bytes To lock the pages of NTAG I 2 C starting at page address 0Fh and onwards, the dynamic lock bytes are used. The dynamic lock bytes are located at page E2h sector 0h (NTAG I 2 C 1k) or address E0h sector 1 (NTAG I 2 C 2k). The three lock bytes cover the memory area of 830 data bytes (NTAG I 2 C 1k) or 1846 data bytes (NTAG I 2 C 2k). The granularity is 16 pages for NTAG I 2 C 1k and 32 pages for NTAG I 2 C 2k compared to a single page for the first 48 bytes (NTAG I 2 C 1k) or the first 64 bytes (NTAG I 2 C 2k) as shown in Figure 11 and Figure 12. Remark: Set all bits marked with RFUI to 0 when writing to the dynamic lock bytes of 62

15 MSB LSB MSB LSB LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE RFUI RFUI LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE bit bit page 226 (E2h) MSB LSB RFUI BL BL BL BL BL BL BL bit aaa Fig 11. NTAG I 2 C 1k Dynamic lock bytes 0, 1 and 2 MSB LSB MSB LSB LOCK PAGE bit bit page 224 (E0h) MSB LSB BL BL BL BL BL BL BL BL LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE RFUI LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE LOCK PAGE Block Locking (BL) bits bit aaa Fig 12. NTAG I 2 C 2k Dynamic lock bytes 0, 1 and of 62

16 The default value of the dynamic lock bytes is h. The value of Byte 3 is always 00h when read. Reading the 3 bytes for the dynamic lock bytes and the Byte 3 (00h) from RF interface (address E2h sector 0 (NTAG I 2 C 1k) or E0h sector 1 (NTAG I 2 C 2k) or from I 2 C (address 38h (NTAG I 2 C 1k) or 78h (NTAG I 2 C 2k)) will also return a fixed value for the next 12 bytes of 00h. Like for the static lock bytes, this process of modifying the dynamic lock bytes is irreversible from RF perspective. If a bit is set to logic 1, it cannot be changed back to logic 0. From I²C perspective, the bits can be reset to Capability Container (CC bytes) The Capability Container CC (page 3) is programmed during the IC production according to the NFC Forum Type 2 Tag specification (see Ref. 1). These bytes may be bit-wise modified by a WRITE command from the I²C or RF interface. See examples for NTAG I 2 C 1k version in Figure 13 and for NTAG I 2 C 2k version in Figure 14. page 3 byte byte E1h 10h 6Dh 00h CC bytes Example NTAG I 2 C 1k version default value (initialized state) CC bytes write command to page result in page 3 (read-only state) aaa Fig 13. CC bytes of NTAG I 2 C 1k version page 3 byte data E1h 10h EAh 00h CC bytes Example NTAG I 2 C 2k version default value (initialized state) CC bytes write command to page result in page 3 (read-only state) aaa Fig 14. CC bytes of NTAG I 2 C 2k version The default values of the CC bytes at delivery are defined in Section of 62

17 8.3.9 User Memory pages Pages 04h to E1h via the RF interface - Block 1h to 37h, plus the first 8 bytes of block 38h via the I 2 C interface are the user memory read/write areas for NTAG I 2 C 1k version. Pages 04h (sector 0) to DFh (sector 1) via the RF interface - Block 1h to 77h via the I 2 C interface are the user memory read/write areas for NTAG I 2 C 2k version. The default values of the data pages at delivery are defined in Section of 62

18 Memory content at delivery The capability container in page 03h and the page 04h and 05h of NTAG I 2 C is pre-programmed to the initialized state according to the NFC Forum Type 2 Tag specification (see Ref. 1) as defined in Table 4 (NTAG I 2 C 1k version) and Table 5 (NTAG I 2 C 2k version). This content is READ only from the RF side and READ&WRITE from the I²C side. The User memory contains an empty NDEF TLV. Remark: The default content of the data pages from page 05h onwards is not defined at delivery. Table 4. Memory content at delivery NTAG I 2 C 1k version Page Address Byte number within page h E1h 10h 6Dh 00h 04h 03h 00h FEh 00h 05h 00h 00h 00h 00h Table 5. Memory content at delivery NTAG I 2 C 2k version Page Address Byte number within page h E1h 10h EAh 00h 04h 03h 00h FEh 00h 05h 00h 00h 00h 00h NTAG I 2 C configuration and session registers NTAG I 2 C functionalities can be configured and read in two separate locations depending if the configurations shall be effective within the communication session (session registers) or by default after Power On Reset (POR) (configuration bits). The configuration registers of pages E8h to E9h (sector 0 or 1 depending if it is for NTAG I²C 1k or 2k) via the RF interface or block 3Ah or 7Ah (depending if it is for NTAG I²C 1k or 2k) via the I 2 C interface, see Figure 5, Figure 6, Figure 7 and Figure 8, are used to configure the default functionalities of the NTAG I 2 C - see Table 6. Those bits values are stored in the EEPROM and represent the default settings to be effective after POR. Their values can be read & written by both interfaces when applicable and when not locked by the register lock bits (see REG_LOCK in Table 9). Table 6. Configuration memory NTAG I²C 1k RF address (sector 0) I 2 C Address Byte number Dec Hex Dec Hex E8h 58 3Ah NC_REG LAST_NDEF_BLOCK SRAM_MIRROR_ WDT_LS BLOCK 233 E9h WDT_MS I2C_CLOCK_STR REG_LOCK 00h fixed of 62

19 Table 7. Configuration memory NTAG I²C 2k RF address (sector 1) I 2 C Address Byte number Dec Hex Dec Hex E8h 122 7Ah NC_REG LAST_NDEF_BLOCK SRAM_MIRROR_ WDT_LS BLOCK 233 E9h WDT_MS I2C_CLOCK_STR REG_LOCK 00h fixed The session registers Pages F8h to F9h (sector 3) via the RF interface or block FEh via I 2 C, see Table 8, are used to configure or monitor the values of the current communication session- see Figure 6 and Figure 8. Those bits can only be read via the RF interface but both read and written via the I 2 C interface. Table 8. Session registers NTAG I²C 1k and 2k RF address (sector 3h) I 2 C Address Byte number Dec Hex Dec Hex F8h 254 FEh NC_REG LAST_NDEF_BLOCK SRAM_MIRROR WDT_LS _BLOCK 249 F9h WDT_MS I2C_CLOCK_STR NS_REG 00h fixed Table 9. Configuration bytes Bit Field Access via RF Both the session and the configuration bits have the same register except the REG_LOCK bits, which are only available in the configuration bits and the NS_REG bits which are only available in the session registers. After POR, the configuration bits are loaded into the session registers. During the communication session, the values can be changed, but the related effect will only be visible within the communication session for the session registers or after POR for the configuration bits. After POR, the registers values will be again brought back to the default configuration values. All registers and configuration default values, access and descriptions are described in Table 9 and Table 10. Reading and writing the session registers via I²C can only be done via the READ & WRITE registers operation - see Section 9.8. Access via I²C Default values NC_REG Description 7 I2C_RST_ON_OFF R&W R&W enables soft reset through I²C repeated start - see Section READ R&W No function - keep at 5 FD_OFF R&W R&W 0 defines the event upon which the signal output on the FD pin is brought up 0 if the field is switched off 01b if the field is switched off or the tag is set to the HALT state 1 if the field is switched off or the last page of the NDEF message has been read (defined in LAST_NDEF_BLOCK) of 62

20 Table 9. continuedconfiguration bytes Bit Field Access via RF Access via I²C Default values Description 4 11b (if FD_ON = 11b) if the field is switched off or if last data is read by I²C (in pass-through mode RF ---> I²C) or last data is written by I²C (in passthrough mode I²C---> RF) 11b (if FD_ON = 0 or 01b or 1) if the field is switched off See Section 8.4 for more details 3 FD_ON R&W R&W 0 defines the event upon which the signal output on the FD pin is brought down 0 if the field is switched on 01b by first valid Start-of-Frame (SoF) 1 by selection of the tag 2 11b (in passthrough mode RF-->I²C) if the data is ready to be read from the I²C interface 11b (in passthrough mode I²C--> RF) if the data is read by the RF interface See Section 8.4for more details 1 - READ R&W No function - keep at 0 TRANSFER_DIR R&W R&W 1b defines the data flow direction for the data transfer From I²C to RF interface 1b From RF to I²C interface In case the passthrough mode is not enabled no WRITE access from the RF side of 62

21 Table 9. continuedconfiguration bytes Bit Field Access via RF Access via I²C Default values LAST_NDEF_BLOCK 7 Address of last BLOCK (16bytes) of NDEF 6 message from I²C addressing. An RF read of the last page of the I2C block, specified by 5 LAST_NDEF_BLOCK sets the register 4 LAST_NDEF_BLOCK R&W R&W 00h NDEF_DATA_READ to 1b and triggers FD_OFF if FD_OFF is set to 1 1h is page 4h (first page of the User Memory) from RF addressing 2h is page 8h 3h is page Ch 37h is page DEh - memory sector 0h (last possible page of User memory for NTAG I²C 1k) 77h is page DCh - memory sector 1h (last page possible of the User Memory for NTAG I²C 2k) SRAM_MIRROR_BLOCK 7 Address of first BLOCK (16bytes) of SRAM 6 buffer when mirrored into the User memory from I²C addressing 5 1h is page 4h (first page of the User Memory) 4 SRAM_MIRROR_ R&W R&W F8h from RF addressing 3 BLOCK 2h is page 8h h is page Ch 34h is page DEh - memory sector 0h (last possible page of User memory for NTAG I²C 1k) 74h is page DCh - memory sector 1h (last page possible of the User Memory for NTAG I²C 2k) WDT_LS Description WDT_LS R&W R&W 48h Least Significant byte of watchdog time 3 control register of 62

22 Table 9. continuedconfiguration bytes Bit Field Access via RF Access via I²C Default values WDT_MS WDT_MS R&W R&W 08h Most Significant byte of watchdog time 3 control register I2C_CLOCK_STR READ READ locked to I2C_CLOCK_STR R&W R&W 1b Enables (1b) or disable () the I²C clock stretching REG_LOCK Description READ READ locked to R&W R&W Enable writing of the configuration bytes via I²C 1b Disable writing of the configuration bytes via I²C One time programmable 0 REG_LOCK R&W R&W 0 Enable writing of the configuration bytes via RF 1b Disable writing of the configuration bytes via RF One time programmable of 62

23 Table 10. Session register bytes Bit Field Access via RF Access via I²C Default values NC_REG Description 7 I2C_RST_ON_OFF READ R&W - see configuration bytes description 6 PTHRU_ON_OFF READ R&W 1b enables data transfer via the SRAM buffer (Passthrough mode) 5 FD_OFF READ R&W 4 3 FD_ON READ R&W - see configuration bytes description 2 1 SRAM_MIRROR_ READ R&W 1b enables SRAM mirroring ON_OFF 0 PTHRU_DIR READ R&W see configuration bytes description LAST_NDEF_ BLOCK SRAM_MIRROR_ BLOCK LAST_NDEF_BLOCK READ R&W - see configuration bytes description SRAM_MIRROR_BLOCK READ R&W - see configuration bytes description WDT_LS WDT_LS READ R&W - see configuration bytes description of 62

24 Table 10. continuedsession register bytes Bit Field Access via RF Access via I²C Default values WDT_MS WDT_MS READ R&W - see configuration bytes description I2C_CLOCK_STR READ READ - Locked to I2C_CLOCK_STR READ READ See configuration bytes description NS_REG 7 NDEF_DATA_READ READ READ 1b all data bytes read from the address specified in LAST_NDEF_BLOCK. value is reset to when read 6 I2C_LOCKED READ R&W 1b Memory access is locked to the I²C interface 5 RF_LOCKED READ READ 1b Memory access is locked to the RF interface 4 SRAM_I2C_READY READ READ 1b data is ready in SRAM buffer to be read by I2C 3 SRAM_RF_READY READ READ 1b data is ready in SRAM buffer to be read by RF 2 EEPROM_WR_ERR READ R&W 1b HV voltage error during EEPROM write or erase cycle via I²C needs to be written back to "" to be cleared 1 EEPROM_WR_BUSY READ READ 1b EEPROM write cycle in progress - access to EEPROM disabled EEPROM access possible 0 RF_FIELD_PRESENT READ READ 1b RF field is detected 8.4 Configurable Field Detection Pin Description The field detection feature provides the capability to trigger an external device (e.g. Controller) or switch on the connected circuitry by an external power management unit depending on activities on the RF interface of 62

25 The conditions for the activation of the field detection signal (FD_ON) can be: The presence of the RF field The detection of a valid command (Start-of-Frame) The selection of the IC. The conditions for the de-activation of the field detection signal (FD_OFF) can be: The absence of the RF field The detection of the HALT state The RF interface has read the last part of the NDEF message defined with LAST_NDEF_MESSAGE All the various combinations of configurations are described in Table 9 and illustrated in Figure 15, Figure 16 and Figure 17 for all various combination of the filed detection signal configuration. The field detection pin can also be used as a handshake mechanism in the Pass-through mode to signal to the external microcontroller if New data are written to SRAM on the RF interface Data written to SRAM from the microcontroller are read via the RF interface. See Section 11 for more information on this handshake mechanism of 62

26 ON RF field OFF HIGH FD pin LOW I 2 C EVENT RF RF field switches ON RF field switches OFF REGISTERS NS_REG NC_REG NDEF_DATA_READ I2C_LOCKED RF_LOCKED SRAM_I2C_READY SRAM_RF_READY EEPROM_WR_ERR EEPROM_WR_BUSY RF_FIELD_PRESENT 1b 1b I2C_RST_ON_OFF PTHRU_ON_OFF FD_ON FD_OFF SRAM_MIRROR_ON_OFF PTHRU_DIR 1b 1b aaa Fig 15. Illustration of the field detection feature when configured for simple field detection of 62

27 ON RF field OFF HIGH FD pin LOW I 2 C EVENT RF First valid State-of- Frame RF field switches OFF or tag set to the HALT state NS_REG NDEF_DATA_READ I2C_LOCKED RF_LOCKED SRAM_I2C_READY SRAM_RF_READY EEPROM_WR_ERR REGISTERS NC_REG EEPROM_WR_BUSY RF_FIELD_PRESENT 1b 1b I2C_RST_ON_OFF PTHRU_ON_OFF FD_ON 1b 1b FD_OFF 1b 1b SRAM_MIRROR_ON_OFF PTHRU_DIR 1b 1b aaa Fig 16. Illustration of the field detection feature when configured for First valid state of Frame detection of 62

28 ON RF field OFF HIGH FD pin LOW I 2 C EVENT RF Selection of the tag RF field switches OFF or RF read the last 4 bytes of the NDEF message defined in LAST_NDEF_MESSAGE REGISTERS NS_REG NC_REG NDEF_DATA_READ I2C_LOCKED RF_LOCKED SRAM_I2C_READY SRAM_RF_READY EEPROM_WR_ERR EEPROM_WR_BUSY RF_FIELD_PRESENT 1b 1b I2C_RST_ON_OFF PTHRU_ON_OFF FD_ON FD_OFF 1b 1b 1b 1b 1b 1b 1b 1b SRAM_MIRROR_ON_OFF PTHRU_DIR 1b 1b 1b 1b aaa Fig 17. Illustration of the field detection feature when configured for selection of the tag detection 8.5 Watchdog timer In order to allow the I²C interface to perform all necessary commands (READ, WRITE), the memory access remains locked to the I²C interface til the register I2C_LOCKED is cleared by the host - see Table 10. In order however to avoid that the memory stays 'locked' to the I²C for a long period of time, it is possible to program a watchdog timer to unlock the I 2 C host from the tag, so that the RF reader can access the tag after a period of time of inactivity. The host itself will not be notified of this event directly, but the NS_REG register is updated accordingly (the register bit I2C_LOCKED will be cleared - see Table 10). The default value is set to 20 ms (848h), but the watch dog timer can be freely set from 0001h (9.43 s) up to FFFFh ( s). The timer starts ticking when the communication between the NTAG I 2 C and the I 2 C interface starts. In case the of 62

29 communication with the I 2 C is still going on after the watchdog timer expires, the communication will continue until the communication has completed. Then the status register I2C_LOCKED will be immediately cleared. In the case where the communication with the I 2 C interface has completed before the end of the timer and the status register I2C_LOCKED was not cleared by the host, it will be cleared at the end of the watchdog timer. The watchdog timer is only effective if the VCC pin is powered and will be reset and stopped if the NTAG I 2 C is not VCC powered or if the register status I2C_LOCKED is set to 0 and RF_LOCKED is set to Energy harvesting The NTAG I 2 C provides the capability to supply external low power devices with energy generated from the RF field of a NFC device. The voltage and current from the energy harvesting depend on various parameters, such as the strength of the RF field, the tag antenna size, or the distance from the NFC device. At room temperature, NTAG I 2 C could provide typically 5 ma at 2 V on the VOUT pin with an NFC Phone. Operating NTAG I 2 C in energy harvesting mode requires a number of precautions: A significant buffer capacitor in the range of typically 10nF up to 100 nf maximum shall be connected between VOUT and GND close to the terminals. If NTAG I 2 C also powers the I 2 C bus, then VCC must be connected to VOUT, and pull-up resistors on the SCL and SDA pins must be sized to control SCL and SDA sink current when those lines are pulled low by NTAG I 2 C or the I 2 C host If NTAG I 2 C also powers the Field Detect bus, then the pull-up resistor on the Field Detect line must be sized to control the sink current into the Field Detect pin when NTAG I 2 C pulls it low The NFC reader device communicating with NTAG I 2 C shall apply polling cycles including an RF Field Off condition of at least 5.1 ms as defined in NFC Forum Activity specification (see Ref. 4, chapter 6). Note that increasing the output current on the V out decreases the RF communication range of 62

30 9. I²C commands For details about I 2 C interface refer to Ref. 3. SCL SDA Start Condition SDA Input SDA Change Stop Condition SCL SDA MSB ACK Start Condition SCL SDA MSB ACK Stop Condition 001aao231 Fig 18. I 2 C bus protocol The NTAG I 2 C supports the I 2 C protocol. This protocol is summarized in Figure 18. Any device that sends data onto the bus is defined as a transmitter, and any device that reads the data from the bus is defined as a receiver. The device that controls the data transfer is known as the bus master, and the other as the slave device. A data transfer can only be initiated by the bus master, which will also provide the serial clock for synchronization. The NTAG I 2 C is always a slave in all communications. 9.1 Start condition Start is identified by a falling edge of Serial Data (SDA), while Serial Clock (SCL) is stable in the high state. A Start condition must precede any data transfer command. The NTAG I 2 C continuously monitors SDA (except during a Write cycle) and SCL for a Start condition, and will not respond unless one is given. 9.2 Stop condition Stop is identified by a rising edge of SDA while SCL is stable and driven high. A Stop condition terminates communication between the NTAG I 2 C and the bus master. A Stop condition at the end of a Write command triggers the internal Write cycle of 62

31 9.3 Soft reset feature In the case where the I 2 C interface is constantly powered on, NTAG I 2 C can trigger a reset of the I 2 C interface via its soft reset feature- see Table 9. When this feature is enabled, if the microcontroller does not issue a stop condition between two start conditions, this situation will trigger a reset of the I 2 C interface and hence may hamper the communication via the I 2 C interface. 9.4 Acknowledge bit (ACK) The acknowledge bit is used to indicate a successful byte transfer. The bus transmitter, whether it is the bus master or slave device, releases Serial Data (SDA) after sending eight bits of data. During the 9th clock pulse period, the receiver pulls Serial Data (SDA) low to acknowledge the receipt of the eight data bits. 9.5 Data input During data input, the NTAG I 2 C samples SDA on the rising edge of SCL. For correct device operation, SDA must be stable during the rising edge of SCL, and the SDA signal must change only when SCL is driven low. 9.6 Addressing To start communication between a bus master and the NTAG I 2 C slave device, the bus master must initiate a Start condition. Following this initiation, the bus master sends the device address. The NTAG I 2 C address from I 2 C consists of a 7-bit device identifier (see Table 11 for default value). The 8th bit is the Read/Write bit (RW). This bit is set to 1 for Read and 0 for Write operations. If a match occurs on the device address, the NTAG I 2 C gives an acknowledgment on SDA during the 9th bit time. If the NTAG I 2 C does not match the device select code, it deselects itself from the bus and clear the register I2C_LOCKED (see Table 8). Table 11. Default NTAG I 2 C address from I 2 C Device address R/W b7 b6 b5 b4 b3 b2 b1 b0 Value 1 [1] 0 [1] 1 [1] 0 [1] 1 [1] 0 [1] 1 [1] 1/0 [1] Initial values - can be changed. The I 2 C address of the NTAG I 2 C (byte 0 - block 0h) can only be modified by the I 2 C interface. Both interfaces have no READ access to this address and a READ command from the RF or I²C interface to this byte will only return 04h (manufacturer ID for NXP Semiconductors - see Figure 9) of 62

32 of 62 Fig 19. Host Tag Host Tag xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx Write: 9.7 READ and WRITE Operation Start Read: Start 7 bits SA and 0 7 bits SA and 0 I 2 C READ and WRITE operation MEMA D0 A A A A MEMA A Stop D1 Start A 7 bits SA and 1 A D15 D0 A Stop A A A D1 D15 Stop aaa NXP Semiconductors

33 The READ and WRITE operation handle always 16 bytes to be read or written (one block - see Figure 8) For the READ operation (see Figure 19), following a Start condition, the bus master/host sends the NTAG I 2 C slave address code (SA - 7 bits) with the Read/Write bit (RW) reset to 0. The NTAG I 2 C acknowledges this (A), and waits for one address byte (MEMA), which should correspond to the address of the block of memory (SRAM or EEPROM) that is intended to be read. The NTAG I 2 C responds to a valid address byte with an acknowledge (A). A Stop condition can be then issued. Then the host again issues a start condition followed by the NTAG I 2 C slave address with the Read/Write bit set to 1. The NTAG I 2 C acknowledges this (A) and sends the first byte of data read (D0).The bus master/host acknowledges it (A) and the NTAG I 2 C will subsequently transmit the following 15 bytes of memory read with an acknowledge from the host after every byte. After the last byte of memory data has been transmitted by the NTAG I 2 C, the bus master/host will acknowledge it and issue a Stop condition. For the WRITE operation (see Figure 19), following a Start condition, the bus master/host sends the NTAG I 2 C slave address code (SA - 7 bits) with the Read/Write bit (RW) reset to 0. The NTAG I 2 C acknowledges this (A), and waits for one address byte (MEMA), which should correspond to the address of the block of memory (SRAM or EEPROM) that is intended to be written. The NTAG I 2 C responds to a valid address byte with an acknowledge (A) and, in the case of a WRITE operation, the bus master/host starts transmitting each 16 bytes (D0D15) that shall be written at the specified address with an acknowledge of the NTAG I²C after each byte (A). After the last byte acknowledge from the NTAG I²C, the bus master/host issues a Stop condition. The memory address accessible via the READ and WRITE operations can only correspond to the EEPROM or SRAM (respectively 00h to 3Ah or F8h to FBh for NTAG I²C 1k and 00h to 7Ah or F8h to FBh for NTAG I²C 2k) of 62

34 of 62 xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx 9.8 WRITE and READ register operation In order to modify or read the session register bytes (see Table 10), NTAG I²C requires the WRITE and READ register operation (see Figure 20). Host Tag Host Tag Fig 20. Write: Start Read: Start 7 bits SA and 0 7 bits SA and 0 MEMA WRITE and READ register operation A MEMA A REGA REGA A MASK Stop Start 7 bits SA and 1 A A A A A REGDAT A Stop REGDAT A Stop aaa NXP Semiconductors

35 For the READ register operation, following a Start condition the bus master/host sends the NTAG I²C slave address code (SA - 7 bits) with the Read/Write bit (RW) reset to 0. The NTAG I 2 C acknowledges this (A), and waits for one address byte (MEMA) which corresponds to the address of the block of memory with the session register bytes (FEh). The NTAG I 2 C responds to the address byte with an acknowledge (A). Then the bus master/host issues a register address (REGA), which corresponds to the address of the targeted byte inside the block FEh (00h, 01hto 07h) and then waits for the Stop condition. Then the bus master/host again issues a start condition followed by the NTAG I²C slave address with the Read/Write bit set to 1. The NTAG I²C acknowledges this (A), and sends the selected byte of session register data (REGDAT) within the block FEh. The bus master/host will acknowledge it and issue a Stop condition. For the WRITE register operation, following a Start condition, the bus master/host sends the NTAG I²C slave address code (SA - 7 bits) with the Read/Write bit (RW) reset to 0. The NTAG I 2 C acknowledges this (A), and waits for one address byte (MEMA), which corresponds to the address of the block of memory within the session register bytes (FEh). After the NTAG I 2 C acknowledge (A), the bus master/host issues a MASK byte that defines exactly which bits shall be modified by a 1 bit value at the corresponding bit position. Following the NTAG I²C acknowledge (A), the new register data (one byte - REGDAT) to be written is transmitted by the bus master/host. The NTAG I²C acknowledges it (A), and the bus master/host issues a stop condition of 62

36 10. RF Command NTAG activation follows the ISO/IEC Type A specification. After NTAG I 2 C has been selected, it can either be deactivated using the ISO/IEC HALT command, or NTAG commands (e.g., READ or WRITE) can be performed. For more details about the card activation refer to Ref NTAG I 2 C command overview All available commands for NTAG I 2 C are shown in Table 12. Table 12. Command overview Command [1] ISO/IEC NFC FORUM Command code (hexadecimal) Request REQA SENS_REQ 26h (7 bit) Wake-up WUPA ALL_REQ 52h (7 bit) Anticollision CL1 Anticollision CL1 SDD_REQ CL1 93h 20h Select CL1 Select CL1 SEL_REQ CL1 93h 70h Anticollision CL2 Anticollision CL2 SDD_REQ CL2 95h 20h Select CL2 Select CL2 SEL_REQ CL2 95h 70h Halt HLTA SLP_REQ 50h 00h GET_VERSION h READ - READ 30h FAST_READ - - 3Ah WRITE - WRITE A2h SECTOR_SELECT SECTOR_SELECT C2h [1] Unless otherwise specified, all commands use the coding and framing as described in Ref Timing The command and response timing shown in this document are not to scale and values are rounded to 1 s. All given command and response times refer to the data frames, including start of communication and end of communication. They do not include the encoding (like the Miller pulses). An NFC device data frame contains the start of communication (1 start bit ) and the end of communication (one logic bit length of unmodulated carrier). An NFC tag data frame contains the start of communication (1 start bit ) and the end of communication (1 bit length of no subcarrier). The minimum command response time is specified according to Ref. 1 as an integer n, which specifies the NFC device to NFC tag frame delay time. The frame delay time from NFC tag to NFC device is at least 87 s. The maximum command response time is specified as a time-out value. Depending on the command, the T ACK value specified for command responses defines the NFC device to NFC tag frame delay time. It does it for either the 4-bit ACK value specified or for a data frame. All timing can be measured according to the ISO/IEC frame specification as shown for the Frame Delay Time in Figure 21. For more details refer to Ref of 62

37 last data bit transmitted by the NFC device first modulation of the NFC TAG FDT = (n* )/fc 128/fc logic 1 256/fc end of communication (E) FDT = (n* )/fc 128/fc start of communication (S) 128/fc logic 0 256/fc end of communication (E) 128/fc start of communication (S) aaa Fig 21. Frame Delay Time (from NFC device to NFC tag), T ACK and T NAK Remark: Due to the coding of commands, the measured timings usually excludes (a part of) the end of communication. Consider this factor when comparing the specified with the measured times NTAG ACK and NAK NTAG uses a 4 bit ACK / NAK as shown in Table 13. Table 13. Code (4-bit) Ah 0h 1h 3h 7h ACK and NAK values ACK/NAK Acknowledge (ACK) NAK for invalid argument (i.e. invalid page address) NAK for parity or CRC error NAK for Arbiter locked to I²C NAK for EEPROM write error 10.4 ATQA and SAK responses NTAG I 2 C replies to a REQA or WUPA command with the ATQA value shown in Table 14. It replies to a Select CL2 command with the SAK value shown in Table 15. The 2-byte ATQA value is transmitted with the least significant byte first (44h). Table 14. ATQA response of the NTAG I 2 C Bit number Sales type Hex value NTAG I 2 C 00 44h Table 15. SAK response of the NTAG I 2 C Bit number Sales type Hex value NTAG I 2 C 00h of 62