## Technical Overview: M24C04-R EEPROM The **M24C04-R** is a 4-Kbit serial I2C (Inter-Integrated Circuit) Electrically Erasable Programmable Read-Only Memory (EEPROM). It is manufactured by STMicroelectronics and is designed for low-voltage, low-power applications. --- ### 1. Key Technical Specifications | Parameter | Value | | :--- | :--- | | **Storage Capacity** | 4 Kbits (512 bytes) | | **Memory Organization** | 2 blocks of 256 bytes (512 x 8 bits) | | **Operating Voltage ($V_{CC}$)** | 1.8V to 5.5V | | **Interface** | I2C Serial (Two-Wire) | | **Clock Frequency** | 400 kHz (Fast Mode), 1 MHz (Fast Mode Plus) | | **Endurance** | 4 Million write cycles | | **Data Retention** | 200 Years | | **Write Time** | 5 ms (Max) | --- ### 2. Pin Configuration (Typical 8-pin Package) Most M24C04-R units come in SO8, TSSOP8, or UFDFPN8 packages. | Pin Number | Name | Description | | :--- | :--- | :--- | | **1, 2** | NC / DU | Not Connected / Don't Use (In this specific model, these are not used for addressing). | | **3** | E2 | Chip Enable input (used to hardware-address multiple chips). | | **4** | $V_{SS}$ | Ground. | | **5** | SDA | Serial Data (Bidirectional). | | **6** | SCL | Serial Clock. | | **7** | WC | Write Control (Active High). Connect to $V_{SS}$ for normal write operations. | | **8** | $V_{CC}$ | Supply Voltage. | --- ### 3. Functional Features #### I2C Protocol & Addressing The device uses a standard I2C protocol. For the 4-Kbit version, the device is split into two 256-byte blocks. * The device address is `1010` (fixed) + `E2` (hardware pin) + `P0` (block select bit) + `R/W`. * This allows up to two M24C04 devices to be on the same I2C bus by toggling the **E2** pin. #### Write Protection (WC Pin) The **Write Control (WC)** pin is a hardware protection feature: * **WC at $V_{IL}$ (Low):** The entire memory can be written to. * **WC at $V_{IH}$ (High):** The memory is write-protected (read-only mode). #### Page Write The device supports a **16-byte Page Write** mode. This allows up to 16 bytes to be written in a single command, significantly speeding up the programming process compared to byte-by-byte writing. --- ### 4. Typical Application Circuit To integrate the M24C04-R into a microcontroller system (like Arduino or STM32), follow this basic logic: ```c // Example I2C Write Logic (Pseudocode) 1. START Condition 2. Send Device Address (0xA0 for Block 0, Write mode) 3. Send Byte Address (0x00 to 0xFF) 4. Send Data Byte 5. STOP Condition 6. Wait 5ms (Self-timed Write Cycle) ``` ---