### Overview of the M24C01-R The **M24C01-R** is a specific variant of the 1-Kbit serial I2C Bus EEPROM (Electrically Erasable Programmable Read-Only Memory) manufactured by STMicroelectronics. The "-R" suffix specifically denotes the operating voltage range and environmental specifications. --- ### Technical Specifications The following table summarizes the key electrical and physical characteristics of the M24C01-R: | Feature | Specification | | :--- | :--- | | **Memory Size** | 1 Kbit (128 bytes x 8 bits) | | **Interface** | I²C (Inter-Integrated Circuit) | | **Supply Voltage ($V_{CC}$)** | 1.8V to 5.5V | | **Clock Frequency** | Up to 400 kHz (Fast Mode) | | **Write Cycles** | More than 4 million cycles | | **Data Retention** | More than 200 years | | **Write Time** | 5 ms (Byte or Page write) | | **Operating Temp** | -40°C to +85°C | --- ### Pin Configuration and Functions The device is typically found in small packages like SO8, TSSOP8, or UFDFPN8. The pinout is standard for the 24C series: 1. **E0, E1, E2 (Chip Enable):** Used to set the hardware address of the device. Up to 8 devices can share the same I2C bus. 2. **VSS:** Ground. 3. **SDA (Serial Data):** Bi-directional pin used to transfer data in and out. 4. **SCL (Serial Clock):** Synchronizes the data transfer. 5. **WC (Write Control):** A hardware protection pin. * If tied to $V_{SS}$ (Low), write operations are enabled. * If tied to $V_{CC}$ (High), the memory is write-protected. 6. **VCC:** Power supply. --- ### Key Features of the "-R" Variant The **M24C01-R** is distinct from the standard M24C01 due to its low-voltage optimization: * **Low Voltage Operation:** The "R" signifies a wide voltage range of **1.8V to 5.5V**. This makes it ideal for battery-powered handheld devices (like smartphones or IoT sensors) where power efficiency is critical. * **ECOPACK®:** It is compliant with RoHS and "green" standards (lead-free and halogen-free). --- ### Programming Logic (I2C) To interact with the M24C01-R, the microcontroller sends a 7-bit Device Select Code. For this specific chip, the code is `1010` followed by the state of the E2, E1, and E0 pins. ```c // Example Pseudo-code for a Write Operation Start_Condition(); Send_Byte(0xA0); // Device Address (1010 + E2,E1,E0 + Write Bit) Send_Byte(0x00); // Memory Address to write to (0 to 127) Send_Byte(Data_Byte); // The data to store Stop_Condition(); ``` ---