 We will start with the overview of the interfaces, memory, special features and supporting ecosystem. The SD25DV memory comes in 416 and 64kbit devices. All SD25DV has 256 bytes fast transfer mode buffer. There are also special features such as energy harvesting, power management and interface arbitration and also GPL which is a configurable GPIO for different trigger-on events. Temperature ranges from 40°C to 85°C and operating voltage can go from 1.8V to 5.5V and the SD25DV is pin-to-pin compatible with the M24LR product line. The SD25DV-I2C can be connected to a microcontroller such as the SEM32. On the other hand, it can be powered by an RF field. Two pins are supported. The 12 pins version allow usage of low power down and sold power supply for the GPIO circuitry. The M24LR compatibility is mainly focused at the 8 pin package whereas the M24LR does not come in the 12 pin package. Now let's look at the interfaces of the SD25DV. The I2C interface of the SD25DV allows the memory, EEPROM and 256 byte RAM buffer to be accessed similar to a typical EEPROM. Standard random and sequential read mode with automatic address increment. The SD25DV complies to standard ISO 15693 commands along with Amendment 3 and 4. This protocol has a maximum data rate of 53k bits per second when proprietary fast commands are used. For EEPROM, single block programming time is roughly 5ms and the chip capacity is 28.5 picofarad which translates to an antenna inductance of around 4.7 mH. Within the ISO 15693 specification, a 13.56MHz carrier frequency is used. From reader to tag, 10% or 100% amplitude chip keying modulation is used which results in bitrate ranging from 26k bit per second to 1.6 bit per second. From the tag to the reader, the load modulation is based on Manchester coding. Single subcarrier in low 6.6k bit per second or dual subcarrier in high 26k bit per second. The NFC forums subsequently classify tag type V or 5 to be restricted to only 100% modulation, one quarter coding, and single subcarrier. High data rate along with capability container and end depth file formatting. When accessing block with 16 bit address, you will need to use extended commands where block address is coded on 2 bytes. For error management, the SD25DV does not answer to wrong inventory and stay quiet commands. Now let's look at the SD25DV memory. There are three main parts of the SD25DV memory. The EEPROM 256 bytes fast transfer mode buffer and device identification. The SD25DV memory is organized into four main sections. One is the user memory with four configuration areas that can be protected by 64 bit passwords. Section 2 contains all the system configurations in EEPROM. Static registers that define boot behavior at boot, device identifiers and passwords. Remember that accesses to system configuration requires passwords. Section 3 allows dynamic configuration via volatile registers. These facilities storage of status and temporary configuration. Finally, Section 4 comprises the fast transfer mode buffer where maximum of 256 bytes messages improve data between I2C and RF. Let's review the EEPROM user memory in details. SD implements our robust EEPROM sales in the SD25DV. This non-volatile memory can have up to 40 years of data retention and 1 million read-write cycles. The memory is first initialized to 0 hex in factory. RF granularity is at 4 bytes block from 0 hex to 7 ff hex. For memory blocks beyond the 8 kbit boundary, extended commands must be used where block address is encoded in 2 bytes. For I2C accesses, the granularity is byte from 0 to 1 fff hex. The SD25DV stores static system configuration in EEPROM. To access it, you need to use special RF commands for both reads and writes. As a result, system configuration access maintain byte granularity. The dynamic registers are not stored in EEPROM to maintain its volatile nature. Their main purpose is allowing temporary modification of some configuration and providing dynamic activity status. There is no delay in writes and content is not protected by password. Some dynamic registers supporting GPO, EH mode and RF management are shadows of the actual static registers during boot. The fast transfer mode mailbox is a 256 bytes volatile buffer accessible by only special RF commands. Write accesses can only occur when the fast transfer mode is activated and mailbox is empty. The mailbox is not protected by password and write is immediate versus EEPROM. And finally, the remaining memory is read only and dedicated to device identification. Here the UID or unique identifier is coded over 64 bits of information. One can also find the memory size, block size, IC reference, product code, IC revision, application family and data storage format identifiers. Now let's do some example involving EEPROM reading and writing. We'll do it via RF so the SD25DV discovery board does not need to be powered. First connect the SD25R3911B discovery board to your PCUSB port. Then put the SD25DV antenna near the SD25R3911B board. You can put them on top each other or side by side but make sure they are close enough so that RF communication can occur. Then run the SD25R3911B GUI software. First click on the SD25 tag editor button. Pull down the menu under ISO 15693 tab. Then click on dynamic NFC tags and select SD25DV04K. That will open up another GUI window. Now click on the EEPROM tab. In the RF block windows, select block address from 0 to 8. Then click on read single block button as denoted by step number 2. The content of the memory of all 9 blocks will be displayed on the right side of the screen. Ok, let's write to the EEPROM next. Start with RF block window. Put in 0 to 8. In the write single block box, put in 12. If the writes are successful, you should see no error messages returned from the reader. After that, you can perform the read EEPROM as previously done to view the data. You can also read the device identification. Click on AFI or DSFID info tab next to the inventory. Then click on guest system info button. You should get a return data showing the UID, DSFID, AFI, block number, block size, and IC reference.