## Technical Overview of the M24M02-R The **M24M02-R** is a high-density, low-voltage Serial I²C (Inter-Integrated Circuit) EEPROM (Electrically Erasable Programmable Read-Only Memory) manufactured by STMicroelectronics. It features a memory capacity of **2 Megabits (256 KB)**. ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Memory Size** | 2 Megabits (2,097,152 bits) | | **Organization** | 256,000 words of 8 bits each (256 KB) | | **Interface** | I²C Serial (2-wire) | | **Clock Frequency** | 1 MHz (Fast-mode Plus), 400 kHz, 100 kHz | | **Operating Voltage** | 1.8V to 5.5V | | **Page Size** | 256 Bytes | | **Write Endurance** | 4 Million cycles | | **Data Retention** | 200 Years | --- ### 2. Pin Configuration and Functions The device is typically available in SO8, TSSOP8, or WLCSP packages. Below is the standard pinout description: 1. **A1, A2 (Address Inputs):** Used to set the hardware chip address. This allows multiple devices to share the same I²C bus. 2. **SDA (Serial Data):** The bidirectional pin used to transfer data in and out of the device. 3. **SCL (Serial Clock):** The input signal used to synchronize all data transfers. 4. **WP (Write Control):** Hardware write protection. When connected to $V_{CC}$, write operations are disabled. 5. **VSS/VCC:** Ground and Power Supply pins. --- ### 3. Operational Characteristics #### I²C Addressing The M24M02-R uses a specific addressing scheme to handle its large memory space. Because it is a 2-Mbit device, it requires more than 16 bits of internal addressing. It uses: * **Device Select Code:** `1010` (standard for EEPROMs). * **Address Bits:** The device selection includes a bit to choose between the upper and lower 1-Mbit blocks. #### Write Operations * **Byte Write:** Writing a single byte to a specific address. * **Page Write:** Writing up to 256 bytes in a single burst, provided they stay within the same page boundary. * **Self-Timed Cycle:** Once a write command is sent, the chip manages the internal burning process independently (typically takes 5ms). #### Power Management The "R" suffix in M24M02-R indicates it is optimized for low-voltage environments (down to 1.8V), making it ideal for battery-powered applications such as wearables or handheld sensors. --- ### 4. Comparison with Other Models | Model | Capacity | Max Speed | Voltage Range | | :--- | :--- | :--- | :--- | | **M24M02-R** | 2 Mbit | 1 MHz | 1.8V - 5.5V | | **M24M01-R** | 1 Mbit | 1 MHz | 1.8V - 5.5V | | **M24C64** | 64 Kbit | 1 MHz | 1.7V - 5.5V | ---