## Technical Overview: M95640-RMB6P The **M95640-RMB6P** is a high-performance, low-voltage **Serial SPI (Serial Peripheral Interface) EEPROM** manufactured by STMicroelectronics. It offers 64 Kbits of non-volatile memory and is designed for applications requiring reliability and low power consumption. --- ### 1. Key Technical Specifications | Parameter | Details | | :--- | :--- | | **Memory Size** | 64 Kbit (8,192 x 8 bits) | | **Interface** | SPI (Mode 0 and Mode 3) | | **Max Clock Frequency** | 20 MHz (at 4.5V - 5.5V) / 5 MHz (at 1.8V) | | **Supply Voltage (Vcc)** | 1.8V to 5.5V | | **Operating Temperature** | -40°C to +85°C | | **Package Type** | UFDFPN8 (MLP8) - Ultra-thin Fine Pitch Dual Flat No-lead | | **Endurance** | 4 million write cycles | | **Data Retention** | 200 years | --- ### 2. Functional Pins and Descriptions The device typically uses an 8-pin configuration. Below are the primary signal functions: 1. **S (Chip Select):** Activates the device when pulled low. 2. **D (Serial Data Input):** Used to transfer data into the device. 3. **Q (Serial Data Output):** Used to read data out of the device. 4. **C (Serial Clock):** Provides the timing for the serial interface. 5. **W (Write Protect):** Hardware protection to prevent unauthorized write operations. 6. **HOLD:** Pauses serial communication without deselecting the device. 7. **Vcc/Vss:** Power supply and ground pins. --- ### 3. Core Features * **Byte and Page Write:** Supports writing a single byte or a full page (up to 32 bytes) in a single write cycle. * **Self-Timed Write Cycle:** The internal write cycle is triggered automatically and typically completes within **5ms**. * **Block Protection:** Status registers allow the user to software-protect quarter, half, or the entire memory array. * **Low Power Consumption:** * Active Read Current: < 2 mA * Standby Current: < 1 µA (at 1.8V) --- ### 4. Part Number Breakdown: M95640-RMB6P * **M95:** SPI family EEPROM. * **640:** 64 Kbit capacity. * **-R:** Operating voltage range of 1.8V to 5.5V. * **MB:** Package code for UFDFPN8 (2x3 mm). * **6:** Industrial temperature range (-40°C to +85°C). * **P:** RoHS compliant and Halogen-free (Plating). --- ### 5. Implementation Example (C Snippet) This snippet demonstrates a basic SPI command structure to read from the EEPROM: ```c // Define Instruction Opcodes #define READ_CMD 0x03 #define WRITE_CMD 0x02 #define WREN_CMD 0x06 // Write Enable void read_eeprom_data(uint16_t address) { CS_Low(); // Select the chip SPI_Transfer(READ_CMD); // Send Read Command SPI_Transfer(address >> 8); // Send MSB of Address SPI_Transfer(address & 0xFF);// Send LSB of Address uint8_t data = SPI_Transfer(0x00); // Receive Data CS_High(); // Deselect } ```