## Overview of the M24164-R The **M24164-R** is a specific variant of the M24164 family of serial EEPROM (Electrically Erasable Programmable Read-Only Memory) devices manufactured by STMicroelectronics. It is designed for low-power applications and uses the **I²C (Inter-Integrated Circuit)** protocol for communication. --- ### Key Technical Specifications The table below summarizes the core technical parameters of the M24164-R: | Parameter | Specification | |:---|:---| | **Memory Size** | 16 Kbits (2048 x 8 bits) | | **Interface** | I²C Serial (2-wire) | | **Operating Voltage ($V_{CC}$)** | 1.8V to 5.5V | | **Clock Frequency** | 400 kHz (Fast Mode) | | **Page Write** | Up to 16 bytes | | **Write Cycle Time** | 5 ms (Maximum) | | **Endurance** | 1 Million Write Cycles | | **Data Retention** | 40 Years | | **Operating Temperature** | -40°C to +85°C | --- ### Pin Configuration and Functions The device is typically found in small packages like SO8 or TSSOP8. The pins are defined as follows: 1. **E0, E1, E2 (Chip Enable):** These pins allow multiple devices to be connected to the same I²C bus. By hardwiring these pins to $V_{CC}$ or Ground, you assign a unique address to the chip. 2. **SDA (Serial Data):** The bidirectional pin used to transfer addresses and data into and out of the device. 3. **SCL (Serial Clock):** The input signal used to synchronize all data transfers. 4. **WC (Write Control):** A hardware protection pin. - If connected to $V_{CC}$, write operations are inhibited (Read-only mode). - If connected to Ground, the memory is write-enabled. 5. **$V_{CC}$ / $V_{SS}$:** Power supply and Ground pins. --- ### Features and Operational Logic #### 1. I²C Protocol Support The M24164-R operates as a **Slave** device on the I²C bus. It supports: * **Start and Stop Conditions:** Initiated by the Master to begin/end communication. * **Acknowledge (ACK):** The device sends a bit to confirm it received data. * **Device Addressing:** A 7-bit address (usually `1010xxx`) followed by a Read/Write bit. #### 2. Memory Segmentation The 16 Kbits are organized into **128 pages of 16 bytes each**. This allows for "Page Write" operations, where you can write up to 16 bytes in a single bus cycle, significantly improving data throughput. #### 3. Low Power Consumption The "-R" suffix specifically denotes the **1.8V to 5.5V** range. This makes it ideal for battery-operated devices (like smartphones or IoT sensors) because it can operate at very low voltages and consumes minimal current during standby. --- ### Example: I²C Addressing Code To communicate with the M24164-R using a microcontroller (like an Arduino or STM32), the device address is typically structured as follows: ```c // Example Device Address (Assuming E0, E1, E2 are grounded) // Binary: 1010 [E2][E1][E0] [R/W] #define M24164_WRITE_ADDR 0xA0 // 1010 000 0 #define M24164_READ_ADDR 0xA1 // 1010 000 1 ```