The **71421LA55PF** is a specific integrated circuit belonging to the **Dual-Port Static RAM (SRAM)** family. It is designed to allow two independent systems (or processors) to access the same memory space simultaneously without interference. --- ### 1. Technical Specifications Below are the primary technical parameters for the 71421LA55PF: | Parameter | Specification | | :--- | :--- | | **Component Type** | High-Speed 2K x 16 Dual-Port Static RAM | | **Density** | 32K-bit (2,048 words × 16 bits) | | **Access Time** | 55 ns (Nanoseconds) | | **Operating Voltage** | 5.0V (±10%) | | **Package Type** | TQFP (Thin Quad Flat Pack) - 80 Pin | | **Power Consumption** | Low Power ("LA" designation) | | **Temperature Range** | Commercial (0°C to +70°C) | --- ### 2. Key Features * **True Dual-Ported Memory:** It features two independent ports (Left and Right) with separate controls, addresses, and I/O pins. This allows for asynchronous read/write operations. * **Automatic Power-down:** The device enters a standby mode when the chip is deselected, saving energy in portable or heat-sensitive applications. * **Master/Slave Selection:** It includes "Busy" logic signals to manage contention if both ports attempt to write to the same location at the exact same time. * **Interrupt Function:** It supports mailbox signaling between processors, allowing one side to notify the other that data is ready. --- ### 3. Pinout and Architecture Overview The 80-pin TQFP package organizes the pins into functional groups: 1. **Address Lines (A0L–A10L / A0R–A10R):** Used to select one of the 2,048 memory locations. 2. **Data I/O (I/O 0L–15L / I/O 0R–15R):** 16-bit wide data bus for each port. 3. **Control Signals:** * **CE (Chip Enable):** Activates the port. * **OE (Output Enable):** Gates the data to the output pins. * **R/W (Read/Write):** Determines the direction of data flow. * **SEM (Semaphore):** Used for resource allocation management. * **UB/LB (Upper Byte/Lower Byte):** Allows byte-level control over the 16-bit word. --- ### 4. Common Applications Due to its ability to bridge two different processing buses, it is commonly found in: * **Digital Signal Processing (DSP):** Buffering data between a CPU and a DSP. * **Network Equipment:** Managing packet buffers between a line card and a switch fabric. * **Industrial Automation:** Communicating between a main controller and a peripheral co-processor. * **Imaging Systems:** Temporary storage for frame buffers accessible by both a camera sensor and a display driver.