## Overview of the AT45DB161B-RU The **AT45DB161B-RU** is a legacy 16-Megabit (2 MB) DataFlash memory chip manufactured by Atmel (now part of Renesas/Adesto). It is specifically designed for high-density applications such as image storage, voice recording, and data logging. --- ### Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Memory Size** | 16 Megabits (2 Megabytes) | | **Organization** | 4,096 pages (528 bytes per page) | | **Operating Voltage** | 2.7V to 3.6V | | **Interface** | Serial Peripheral Interface (SPI) - Modes 0 and 3 | | **Clock Frequency** | Up to 20 MHz | | **Package Type** | 28-lead TSOP (Thin Small Outline Package) | | **Temperature Range** | Industrial (-40°C to +85°C) | --- ### Internal Architecture and Components The AT45DB161B is unique compared to standard Serial Flash because it includes **internal SRAM buffers**, which simplify the programming process. #### 1. Main Memory Array The memory is partitioned into 4,096 pages. Unlike standard Flash which often uses power-of-two page sizes (like 256 or 512 bytes), this chip uses **528 bytes per page**. This extra 16 bytes per page is often used for Error Correction Code (ECC) or metadata. #### 2. Dual SRAM Data Buffers The chip contains two 528-byte SRAM buffers. This allows for: * **Continuous Writing:** You can write data to Buffer 1 while Buffer 2 is transferring data to the main memory. * **Flexible Programming:** You can modify specific bytes within a buffer before committing the whole page to the non-volatile Flash. #### 3. Control Logic The internal logic handles the SPI protocol, command decoding, and the self-timed program/erase cycles. This means the host microcontroller does not need to manage the high-voltage timing required for Flash cell modification. --- ### Feature Summary * **Page Program:** Allows writing an entire page in a single operation (approx. 14ms). * **Block Erase:** Supports 4KB block erasures for faster data management. * **Hardware Protection:** Includes a Write Protect (`/WP`) pin to prevent accidental data corruption. * **Low Power:** Features a CMOS design with low active and standby currents to preserve battery life. --- ### Pin Configuration (28-Pin TSOP) | Pin Name | Function | | :--- | :--- | | **SI** | Serial Data Input | | **SO** | Serial Data Output | | **SCK** | Serial Clock | | **CS** | Chip Select (Active Low) | | **WP** | Write Protect | | **RESET** | Hardware Reset | | **RDY/BUSY** | Ready/Busy Status Indicator | --- ### Status Note The **AT45DB161B** is an "obsolete" or "end-of-life" (EOL) part. Modern designs usually replace it with the **AT45DB161E** or **AT45DB161F** versions, which offer higher speeds (up to 85MHz) and wider voltage ranges.