Tag with virtual memory

Abstract

A pass-through device (15) comprises: a non-contact RFID interface circuit (5) that exchanges payload data (6) with an RFID device (3) located in the same magnetic field (7); a wired contact interface circuit (8) capable of writing and reading payload data to and from the application device (4); a volatile memory (16) for temporarily storing payload data and a non-volatile memory (17) for storing capability information (18) on a memory size in the direct-through device for storing the payload data; buffer management circuitry (19) for managing writing and reading payload data from at least a first buffer (20) and a second buffer (21) in the volatile memory to pass the payload data directly without storing it in the non-volatile memory (17).

Description

Technical Field

[0001] The present invention relates to a through device having a non-contact RFID interface circuit for communicating with an RFID device and a wired contact interface circuit for communicating with an application device, for passing payload data directly between the RFID device and the application device. The through device includes:

[0002] A non-contact RFID interface circuit that exchanges payload data with an RFID device located in the same magnetic field using a block-by-block read / write operation, the block including header information and the payload data;

[0003] The wired contact interface circuit has at least two contact pins for wires to connect the through device to the application device. The wired contact interface circuit is configured to be able to perform a write operation of the payload data received through the non-contact RFID interface circuit to the application device, and is configured to be able to perform a read operation of the payload data transmitted through the non-contact RFID interface circuit from the application device;

[0004] A volatile memory for temporarily storing payload data and a non-volatile memory for storing capacity information regarding the memory size available in the through device for storing payload data. Background Art

[0005] The integrated circuit NT3H2111_2211 of NXP is such a through device, implemented as an NFC tag in home automation and consumer applications. This NFC tag in through mode can transfer payload data from an RFID device to a storage controller unit of an application device such as a display device. Document EP 3 160 165 B1 discloses an RFID device with near field communication (NFC) function, such as a mobile phone. NFC technology is developed by an industry consortium named NFC Forum (http: / / www.nfc-forum.org / ) and is derived from RFID technology. NFC components can operate in the "reader" mode, "card emulation" mode, and "device" mode standardized by ISO 18.092. The NFC component emits a magnetic field through its near field communication non-contact interface, sends data by modulating the amplitude of the magnetic field, and receives data through load modulation and inductive coupling. In the emulation mode, as described in EP 1 327 222, the NFC component operates passively like a transceiver, communicates with another reader, and is regarded as an RFID chip by other readers.

[0006] Figure 1A system 1 according to the prior art is disclosed, which has such a pass-through device implemented as an NFC tag 2, a mobile phone 3, and a display device 4. The NFC tag 2 includes a contactless RFID interface circuit 5, which exchanges payload data 6 with the mobile phone 3, both being located in the same magnetic field 7 with a carrier frequency of 13.56 MHz generated by the mobile phone 3. The NFC Forum uses block-by-block read and write operations to define NDEF messages for exchanging the payload data 6 between the mobile phone 3 and the NFC tag 2, and these blocks include header information and the payload data 6.

[0007] The NFC tag 2 further includes a wired contact interface circuit 8, which has at least two contact pins for wires to connect the NFC tag 2 to the display device 4. The wired contact interface circuit 8 implements an I2C data bus known to those skilled in the art to communicate with the display device 4. The wired contact interface circuit 8 is capable of performing a write operation on the display device 4 to transmit the payload data 6 received through the contactless RFID interface circuit 5, and is capable of performing a read operation from the display device 4 to transmit the payload data 6 from the display device 4 to the NFC tag 2 and then to the mobile phone 3 through the contactless RFID interface circuit 5.

[0008] The display device 4 includes a microcontroller unit 9, which implements an I2C data bus and controls the display 10 to visualize part or all of the payload data 6 received from the mobile phone 3. In this example of the pass-through application, the display device 4 is installed in a store to display the prices of products on the shelves. The user can use the mobile phone 3 to modify the price of a product and send the modified price as the payload data 6 through the NFC tag 2 to the display device 4. This makes it easy to modify the price without the need to implement a wired I2C data bus in the mobile phone 3. Other pass-through applications are known, and such a pass-through device can communicate easily using a contactless RFID interface, especially a contactless NFC interface. Other wired interfaces known to those skilled in the art, such as SPI, UART, or CAN protocols, can also be used.

[0009] The NFC tag 2 further includes a volatile memory implemented as an SRAM 11 for temporarily storing the payload data 6 received via the contactless RFID interface circuit 5 or the wired contact interface circuit 8. In addition, a non-volatile memory implemented as an EEPROM 12 is used for permanently storing the payload data 6, because the SRAM 11 does not have enough storage space to store all the payload data 6 of the pass-through application, and because such permanent storage of the payload data 6 can decouple the transmission processes from the mobile phone 3 to the NFC tag 2 and from the NFC tag 2 to the display device 4 in terms of time.

[0010] The EEPROM 12 is also used to store capacity information 13, which indicates the memory size in the EEPROM 12 of the NFC tag 2 that can be used to store the payload data 6. Different types of NFC tags 2 include EEPROMs 12 with different memory sizes, which enables different pass-through applications with different storage requirements for the payload data 6. If the user starts a pass-through application with the NFC tag 2 in the same magnetic field 7 on the mobile phone 3, the mobile phone 3 sends a read request to the NFC tag 2 in the first step to read the capacity information 13 stored in the EEPROM 12. Only when the capacity information 13 received at the mobile phone 3 indicates that the memory size in the EEPROM 12 is large enough to store all blocks of the payload data 6 required for the pass-through application with block-by-block read and write operations, the mobile phone 3 processes the requested pass-through application. If the memory size in the EEPROM 12 is not sufficient to store all blocks of the payload data 6 required for the pass-through application, the mobile phone 3 will display a message to the user that the selected pass-through application is not possible.

[0011] A disadvantage of this known pass-through device is that the limitation of the storage space in the non-volatile memory related to the price and technical complexity of the pass-through device limits the possibilities of the pass-through applications. Summary of the Invention

[0012] The object of the present invention is to provide a pass-through device, as well as a system of a pass-through device with an RFID device and an application device, and a method processed by the pass-through device, which improves the use of the limited storage space in the non-volatile memory and increases the flexibility in order to use the pass-through device for a wider range of pass-through applications. This object is achieved by the pass-through device according to claim 1 and the system according to claim 6 and the method according to claim 9. The pass-through device of the present invention includes a buffer management circuit for managing the read and write operations of the payload data into at least a first and a second buffer, the buffers having storage space blocks defined in the volatile memory. The buffer management circuit is configured to write the payload data received from the non-contact RFID interface circuit into the second buffer while reading the payload data stored in the first buffer from the first buffer and transmitting it with the wired contact interface circuit. The buffer management circuit is capable of directly transmitting the payload data temporarily stored in the buffer of the volatile memory received from the non-contact RFID interface to the application device through the wired contact interface. There is no need to reserve storage space in the non-volatile memory of the pass-through device, which reduces the cost and complexity of the pass-through device.

[0013] In a preferred embodiment, the data transfer rate via wired communication to the application device is higher than the data transfer rate that the contactless RFID interface circuit can transfer from the RFID device. This enables any amount of payload data to be transferred from the RFID device to the application device without any associated latency and provides a high degree of flexibility in using any type of the through device of the present invention for all types of through applications. This feature is implemented in the mature environment of the NFC Forum specification and NDEF messages by enabling the through device to respond to a read request from the RFID device to read capacity information, which indicates a memory size larger than the actual available memory size in the non-volatile memory.

[0014] In a further preferred embodiment, the buffer management circuit is configured to manage a third buffer or even more buffers in the buffer organization storage space of the volatile memory to buffer a larger amount of payload during a period when the wired contact interface experiences a temporary delay. In other embodiments, the payload data received from the application device via the wired contact interface must be buffered in order to transfer this payload data to the RFID device via the contactless RFID interface. For this embodiment, if the data transfer rate of the wired contact interface is faster than the data transfer rate of the contactless RFID interface, it is advantageous to add more buffers in the volatile memory.

[0015] These and other aspects of the present invention will become apparent and be elucidated with reference to the embodiments described below. Those skilled in the art will understand that various embodiments can be combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A system of an RFID device, an application device, and a through device according to the prior art is shown.

[0017] Figure 2 A system of an RFID device, an application device, and a through device according to the present invention is shown.

[0018] Figure 3 A method of a writing process is shown, which uses a virtual NDEF memory having a first buffer and a second buffer in the non-volatile memory of the through device to transfer payload data from the RFID device to Figure 2 the application device. DETAILED DESCRIPTION

[0019] Figure 1 A system 1 of an RFID device, an application device, and a through device according to the above prior art is shown. A system 14 is shown, which includes an RFID device implemented as a mobile phone 3 and includes an application device implemented as a display device 4, such as based onFigure 2 As explained. System 14 also includes the through device of the present invention, implemented as NFC tag 15 according to the present invention. Those blocks in system 14 that are the same as the blocks in the prior art system 1 are labeled with the same reference numerals in the figures.

[0020] NFC tag 15 includes a contactless RFID interface circuit 5 that exchanges payload data 6 with mobile phone 3, both located in the same magnetic field 7 with a carrier frequency of 13.56 MHz generated by mobile phone 3. Other contactless interfaces can also be used, such as The NFC Forum uses block-by-block read and write operations to define NDEF messages for exchanging payload data 6 between mobile phone 3 and NFC tag 15. These blocks include header information and payload data 6.

[0021] NFC tag 15 also includes a wired contact interface circuit 8 having at least two contact pins for wires to connect NFC tag 15 to display device 4. Wired contact interface circuit 8 implements an I2C data bus known to those skilled in the art to communicate with display device 4. Wired contact interface circuit 8 is capable of performing a write operation on display device 4 to transmit the payload data 6 received through contactless RFID interface circuit 5, and is capable of performing a read operation from display device 4 to transfer the payload data 6 from display device 4 to NFC tag 15 and then to mobile phone 3 through contactless RFID interface circuit 5.

[0022] Display device 4 includes a microcontroller unit 9 that implements an I2C data bus and controls display 10 to display some or all of the payload data 6 received from mobile phone 3. In this example of the through application, display device 4 is installed in a store to display the prices of products on the shelves. The user can use mobile phone 3 to modify the price of a product and send the modified price as payload data 6 to display device 4 through NFC tag 15 by simply holding mobile phone 3 close to NFC tag 15. This makes it easy to modify the price without the need to implement a wired I2C data bus in mobile phone 3. Other through applications are known, and such through devices can communicate easily using a contactless RFID interface, especially a contactless NFC interface. Other wired interfaces known to those skilled in the art, such as SPI or UART or CAN protocols, can also be used to transfer payload data 6 between NFC tag 15 and display device 4.

[0023] The NFC tag 15 also includes a volatile memory implemented as SRAM 16 for temporarily storing or buffering the payload data 6 received via the contactless RFID interface circuit 5 or the wired contact interface circuit 8. In addition, a non-volatile memory implemented as EEPROM 17 is used to store the capacity information 18. The NFC Forum specification "NFC Data Exchange Format Technical Specification" defines the capacity information to indicate the memory size in the EEPROM 12 available in the prior art NFC tag 2 for storing the payload data 6. Different types of NFC tags 2 include EEPROMs 12 with different memory sizes, which enables different pass-through applications to be implemented. If the user activates the mobile phone 3 in the same magnetic field for a pass-through application with the NFC tag 2, the mobile phone 3 sends a read request to the NFC tag 2 in the first step to read the capacity information 13 stored in the EEPROM 12 to check whether a pass-through application can be performed with this NFC tag 2.

[0024] Since the NFC tag 15 according to the present invention is not limited by the memory size of the EEPROM 17 and can permanently store the payload data 6, which will be explained below, the capacity information 18 stored in the EEPROM 17 indicates a memory size larger than the memory size defined in the NFC Forum specification to indicate to the requesting mobile phone 3 that the NFC tag 15 is capable of handling all types of pass-through applications even if a large amount of payload data 6 needs to be transmitted. This enables the flexible use of the NFC tag 15 according to the present invention in a wide range of pass-through applications and reduces the need for various different types of NFC tags 15 with different EEPROM 17 memory sizes.

[0025] To achieve this, the NFC tag 15 includes buffer management circuitry 19 for managing the write operation of payload data 6 received from the contactless RFID interface circuitry 5 to at least a first buffer 20 and a second buffer 21 in the SRAM 16, where the SRAM 16 forms a kind of virtual NDEF memory for pass-through applications. The abbreviation NDEF stands for the NFC Data Exchange Format defined by the NFC Forum. The first buffer 20 and the second buffer 21 can have any number of memory sizes, but advantageously, these buffers are defined with the same number of bits and / or bytes, and the number of bits / bytes of the buffer is adjusted to the block size or a multiple of the block size of the block-by-block read and write operations of the payload data 6. The buffer management circuitry 19 is constructed to manage the read operation of the payload data 6 stored in the first buffer 20 and the second buffer 21, and this data will be transmitted with the wired contact interface circuitry 8 to pass through the payload data 6 without storing the payload data 6 in the EEPROM 17. This reduces the requirement for the memory size of the EEPROM 17 and reduces the number of write and read cycles of the EEPROM 17.

[0026] In addition, the system 14 and the NFC tag 15 are implemented in such a way that the wired contact interface circuit 8 enables a higher data transfer rate from the display device 4 through the wired contact interface circuit 8 than the non-contact RFID interface circuit 5 can transfer from the mobile phone 3. In fact, the wired I2C bus can achieve a data transfer rate of up to 100 kbit / s in the standard mode, and in other modes, the data transfer rate can reach 400 kbit / s, 1 Mbit / s or 3.4 Mbit / s, while the non-contact NFC interface only includes a more limited data transfer rate. This ensures that all payload data 6 received from the mobile phone 3 and written to the first buffer 20 can be read out from the first buffer 20 and transferred to the display device 4 via the I2C bus, while other payload data received from the mobile phone 3 is written to the second buffer 21 by the buffer management circuit 19. This means that the buffer management circuit 19 is constructed to write the payload data 6 received from the non-contact RFID interface circuit 5 to the second buffer 21 or the first buffer 20, and the payload data 6 stored in the first buffer 20 or the second buffer 21 is read from the first buffer 20 or the second buffer 21 and transferred using the wired contact interface circuit 8. This ensures the complete and secure data transfer of all payload data 6 in the direction from the mobile phone 3 via the NFC tag 15 to the display device 4. Since this is the main direction of the payload data 6, i.e., the modified price information, this data transfer can be completed in just a few milliseconds, which simplifies the use and security of transferring all payload data 6. To ensure the secure transfer of all payload data 6 in the other direction from the display device 4 via the NFC tag 15 to the mobile phone 3, more buffers or buffers with more storage space can be implemented in the SRAM 16.

[0027] Figure 1 shows Figure 3 Figure 2A method for a write process 22 of transferring payload data 6 from a mobile phone 3 to a display device 4 using a virtual NDEF memory in an SRAM 16 that uses an NFC tag 15. The mobile phone 3 is located near the NFC tag 15, and the user activates an application in the mobile phone 3 that starts the direct transfer of the payload data 6 to the display device 4. The mobile phone 3 activates the generation of a magnetic field 7, and in a first step 23, the mobile phone 3 requests and receives capacity information 18 stored in an EEPROM 17 via a contactless RFID interface circuit 5. Since this capacity information 18 convinces the mobile phone 3 that the NFC tag 15 will be able to handle the transfer of the payload data 6, the mobile phone 3 starts transferring the payload data 6 of NDEF blocks 4 to 12 block by block into the first buffer 20 in a second step 24 until the first buffer 20 is full. In step 25, the microcontroller unit 9 is notified using a wired contact interface circuit 8 to read the payload data 6 from the first buffer 20 using an I2C bus. In step 26, the microcontroller unit 9 reads this payload data 6 from the first buffer 20 and processes this payload data 6 to display the new price of the product on the shelf at the end of the write process 22. In step 27, simultaneously or shortly thereafter, the payload data 6 of NDEF blocks 13 to 24 is transferred block by block into the second buffer 21 until the second buffer 21 is full. The write process 22 from the mobile phone 3 to the display device 4 continues until all the payload data 6 has been transferred and the display device 4 displays the new price of the product on the shelf. With this virtual NDEF memory in the SRAM 16, there is no need to store the payload data 6 in the EEPROM 17, which enables several advantages.

Claims

1. A pass-through device (15) having a contactless RFID interface circuit (5) for communicating with an RFID device (3) and a wired contact interface circuit (8) for communicating with an application device (4) to pass payload data (6) directly between the RFID device (3) and the application device (4), the pass-through device (5) comprising: The contactless RFID interface circuit (5) that exchanges payload data (6) with the RFID device (3) located in the same magnetic field (7) using block-by-block read and write operations, the block including header information and the payload data (6); The wired contact interface circuit (8) having at least two contact pins for wires to connect the pass-through device (15) to the application device (4), the wired contact interface circuit (8) being configured to be able to perform a write operation of the payload data (6) received through the contactless RFID interface circuit (5) to the application device (4), and being configured to be able to perform a read operation of the payload data (6) to be transmitted through the contactless RFID interface circuit (5) from the application device (4); A volatile memory (16) and a non-volatile memory (17) for temporarily storing payload data (6); A buffer management circuit (19) for managing the write operation of the payload data (6) received from the contactless RFID interface circuit (5) to at least a first buffer (20) and a second buffer (21) in the volatile memory (16), and managing the read operation of the payload data (6) stored in the first buffer (20) and the second buffer (21) to be transmitted through the wired contact interface circuit (8) to pass the payload data (6) directly without storing the payload data (6) in the non-volatile memory (17), characterized in that the non-volatile memory (17) is configured to store capability information (18) about the memory size available in the pass-through device (15) for storing payload data (6), and the pass-through device (15) is configured to receive a read request from the RFID device (3) to read the capability information (18) stored in the non-volatile memory (17), and is configured to transmit the stored capability information (18) indicating that the storage size is larger than the memory size available in the non-volatile memory (17).

2. The through device (15) according to claim 1, wherein, The wired contact interface circuit (8) is capable of enabling a data transmission rate to the application device (4) through wired communication to be higher than the data transmission rate from the RFID device (3) achievable by the contactless RFID interface circuit (5).

3. The through device (15) according to claim 1 or 2, wherein, The buffer management circuit (19) is configured to write the payload data (6) received from the contactless RFID interface circuit (5) into the second buffer (21) / first buffer (20), while reading the payload information (6) stored in the first buffer (20) / second buffer (21) from the first buffer (20) / second buffer (21), and transmitting it through the wired contact interface circuit (8).

4. The through device according to any one of claims 1 to 3, wherein, The buffer management circuit is configured to manage the write operation to at least a third buffer and the read operation from at least the third buffer.

5. A system (14) comprising an RFID device (3), an application device (4), and a pass-through device (15) according to any one of claims 1 to 4, wherein the RFID device (3) emits a magnetic field of a 13.56 MHz transmitter frequency and is configured to communicate based on the near-field communication standard.

6. The system (14) according to claim 5, wherein, The application device (4) includes a microcontroller circuit (9) having at least two contact pins for wires, and at least two wires of the system (14) connect the pass-through device (15) to the application device (4) to transmit the payload data (6).

7. The system (14) according to claim 5 or 6, wherein The application device (4) includes a display to visualize the payload data (6) passed through from the RFID device (3).

8. A method processed by a pass-through device (15) according to any one of claims 1 to 5 for pass-through transmitting payload data (6) from an RFID device (3) to an application device (4) of a system (14) according to any one of claims 5 to 7, wherein, The following steps are processed by the pass-through device (15): · Write the payload data (6) received from the contactless RFID interface circuit (5) into the second buffer (21) / first buffer (20), while reading the payload data (6) stored in the first buffer (20) / second buffer (21) from the first buffer (20) / second buffer (21), and transmitting it through the wired contact interface circuit (8); · Receive a read request from the RFID device (3) to read the capacity information (18) stored in the non-volatile memory (17); ● Transmit the stored capacity information (18), which indicates that the memory size is larger than the available memory size in the non-volatile memory (17).

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