The **STPC Atlas** is a highly integrated, "PC-on-a-chip" SoC (System on Chip) developed by STMicroelectronics. It was designed primarily for the embedded systems market, such as set-top boxes, thin clients, and industrial controllers, combining a CPU core with common PC peripheral controllers. --- ### 1. Core Architecture The STPC Atlas integrates several high-level functions that traditionally required separate chipsets on a motherboard. | Component | Description | | :--- | :--- | | **CPU Core** | 64-bit ST20-compatible or x86-based core (typically clocked at 133MHz) with 8KB of L1 cache. | | **Memory Controller** | Supports SDRAM (64-bit interface) with a maximum addressable space of 128MB to 512MB depending on the sub-revision. | | **Graphics Engine** | Integrated 2D/3D graphics accelerator with support for shared memory architecture (UMA). | | **Video Pipe** | Hardware video scaling and color space conversion (YUV to RGB). | --- ### 2. Key Peripheral Interfaces The "Atlas" variant is known for its robust connectivity suite, making it a "Super I/O" integrated solution. * **PCI Bus Interface:** Acts as a PCI host bridge, allowing the connection of external expansion cards (v2.1 compliant). * **IDE Controller:** Supports dual-channel Ultra DMA 33 for interfacing with Hard Drives or CompactFlash. * **USB:** Integrated USB 1.1 host controller for mouse, keyboard, or low-speed storage. * **Legacy I/O:** Includes standard PC interfaces: * 2x UART (Serial Ports) * 1x Parallel Port (IEEE 1284) * PS/2 Keyboard/Mouse controller. * **Local Bus:** A programmable interface for connecting non-standard peripherals or ROM/Flash memory. --- ### 3. Visual and Display Outputs One of the strengths of the STPC Atlas is its versatile display engine, capable of driving multiple types of screens simultaneously. 1. **VGA Output:** Standard analog RGB output for CRT or LCD monitors. 2. **TFT/LCD Interface:** Digital output for direct connection to flat-panel displays. 3. **TV Encoder:** Integrated NTSC/PAL encoder for direct connection to standard-definition televisions via S-Video or Composite. --- ### 4. Electrical and Thermal Characteristics Designed for embedded environments, the STPC Atlas focuses on low power consumption to avoid the need for active cooling (fans). * **Package:** 388-pin PBGA (Plastic Ball Grid Array). * **Voltage:** Usually operates on a dual-voltage rail (e.g., 2.5V for the core and 3.3V for I/O). * **Operating Temp:** Available in commercial (0°C to 70°C) and industrial (-40°C to 85°C) grades. --- ### Summary Table: STPC Atlas Specs | Feature | Specification | | :--- | :--- | | **Clock Speed** | 133 MHz | | **Architecture** | x86 Compatible | | **Instruction Set** | 486/Pentium class | | **Bus Width** | 64-bit Internal / 32-bit PCI | | **Manufacturing** | 0.25µm CMOS Process | ---