The **FT313HQ-R** is a high-speed USB 2.0 Host Controller developed by FTDI (Future Technology Devices International). It is specifically designed to allow embedded systems (like microcontrollers) to act as a USB Host, enabling them to communicate with USB peripherals such as flash drives, keyboards, and mice. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **USB Standard** | USB 2.0 High Speed (480Mbps) & Full Speed (12Mbps) | | **Interface Type** | 8-bit or 16-bit Parallel Bus (SRAM-like interface) | | **Endpoints** | Supports up to 4 bidirectional endpoints | | **Internal Memory** | 24 KB Configurable RAM for data buffering | | **Supply Voltage** | 3.3V (with 5V tolerant I/O) | | **Package** | 64-pin QFN (High Quality, Tape & Reel) | | **Operating Temp** | -40°C to +85°C (Industrial Grade) | --- ### 2. Major Functional Components The FT313HQ-R architecture consists of several critical electronic blocks that manage the complexity of the USB protocol: #### A. USB Host Controller Engine This block handles the low-level USB signaling, including packet framing, CRC generation, and handshaking. It manages the scheduling of transactions (Bulk, Interrupt, and Isochronous). #### B. Parallel Host Interface Unlike chips that use SPI or I2C, the FT313HQ uses a **parallel interface**. This allows for high-speed data transfers between the system CPU and the USB controller, making it suitable for bandwidth-intensive tasks like video or large file transfers. #### C. Built-in Clock Multiplier It typically uses a 12MHz or 19.2MHz crystal. An internal **Phase-Locked Loop (PLL)** multiplies this frequency to the 480MHz required for USB High-Speed operations. #### D. Power Management The chip includes a power-on-reset circuit and the ability to put the USB bus into "Suspend" mode to save energy, which is vital for battery-operated embedded devices. --- ### 3. Pinout & Connectivity Highlights - **DATA[15:0]:** The bidirectional data bus for communication with the Microcontroller (MCU). - **AD[1:0]:** Address lines used to access internal registers. - **WR_N / RD_N:** Write and Read strobe signals. - **CS_N:** Chip Select signal. - **DM / DP:** The differential pair lines that connect directly to the USB Port. --- ### 4. Typical Application Circuit To use the FT313HQ-R, the hardware designer usually follows this basic integration path: 1. **MCU Connection:** Connect the 8/16-bit data bus to the MCU's external memory interface (EMIF or FSMC). 2. **Clocking:** Attach a 12MHz Crystal to the XTIN/XTOUT pins. 3. **USB Port:** Connect the DP/DM lines to a USB Type-A female connector with appropriate ESD protection. 4. **Firmware:** Implement a USB Host Stack on the MCU to manage the FT313HQ registers.