The **M24LR64E-R** is a unique electronic component developed by STMicroelectronics. It belongs to the category of **Dynamic NFC/RFID tag ICs**, effectively acting as a bridge between wireless NFC communication and wired I2C interfaces. --- ## 1. Core Technical Specifications The M24LR64E-R is a dual-interface Electrically Erasable Programmable Read-Only Memory (EEPROM). | Feature | Specification | | :--- | :--- | | **Memory Size** | 64 Kbits (8192 bytes) | | **Interface 1 (Wired)** | I2C (Up to 400 kHz) | | **Interface 2 (Wireless)** | ISO/IEC 15693 (NFC Forum Type 5) | | **Frequency** | 13.56 MHz | | **Supply Voltage** | 1.8V to 5.5V | | **Energy Harvesting** | Analog output (Vout) for powering external MCU | --- ## 2. Key Electronic Features ### Dual-Interface Architecture The chip can be accessed through two different paths simultaneously or sequentially: 1. **I2C Interface:** Used by a local microcontroller (MCU) on a PCB to read/write data to the memory. 2. **RF Interface:** Used by an external NFC reader or smartphone to read/write data wirelessly via an induction coil antenna. ### Energy Harvesting One of the most significant features of the "E" variant (M24LR64**E**) is its ability to harvest energy from the RF field of the NFC reader. It can output a small amount of regulated voltage to a pin, which can be used to power a low-power microcontroller or sensors, enabling **battery-less** applications. ### Memory Password Protection The device includes 32-bit password protection schemes for both the RF and I2C interfaces, ensuring that sensitive data stored in the 64 Kbit memory is not accessed by unauthorized devices. --- ## 3. Typical Pin Configuration The M24LR64E-R is commonly found in 8-pin SO8 or TSSOP8 packages. | Pin Name | Function | | :--- | :--- | | **AC0 / AC1** | Connection to the 13.56 MHz antenna coil. | | **SDA / SCL** | I2C Data and Clock lines. | | **Vout** | Energy harvesting output voltage. | | **Vcc / Vss** | Power supply and Ground. | | **RF Write Inhibit** | Hardware pin to disable wireless writing. | --- ## 4. Application Examples ```cpp // Logic flow for an M24LR64E system: 1. Smartphone approaches device (NFC Field detected). 2. M24LR64E harvests energy and wakes up the MCU via Vout. 3. MCU reads sensor data and writes it to M24LR64E via I2C. 4. Smartphone reads the updated sensor data via ISO 15693. ``` 1. **Industrial Automation:** Updating configuration parameters of a machine while it is still in the box (unpowered). 2. **Medical Devices:** Storing patient logs or calibration data that can be read by a phone. 3. **Smart Labels:** Electronic shelf labels that update via NFC and require no battery. ---