Alpha PCI 64–275

This manual describes the Alpha PCI 64-275 motherboard, an embedded and real-time technical OEM product designed for high-performance systems running Microsoft Windows NT.

The motherboard features an Alpha 21064A processor operating at 275MHz, supported by Digital's 21072 chipset. Its memory subsystem accommodates up to 512MB of industry-standard 36-bit SIMMs (from 1M x 36 to 16M x 36) in two banks. An external Level 2 (L2) cache, typically 2MB by default, can be configured between 512KB and 8MB.

For I/O, the board offers four 32-bit PCI expansion slots (one shared with ISA) and three 16-bit ISA expansion slots (one shared). Integrated support chips manage keyboard, mouse, diskette, two serial ports (UARTs), an IDE interface, and a parallel port.

Configuration options, including clock frequency and L2 cache size/speed, are managed through both software and hardware jumpers. A 1MB flash ROM stores the ARC firmware console, which handles power-up diagnostics, system initialization, and a debug monitor, crucial for booting the Windows NT operating system.

To set up a complete system, users require specific hardware components such as SIMMs, a standard PC power supply (275W with 3.3Vdc output), a compatible graphics card, keyboard, mouse, and storage devices (IDE/SCSI hard drive, CD-ROM, diskette drive). The board itself measures 22.1 cm x 33.0 cm (Baby-AT form factor) and operates within a 10°C to 40°C ambient temperature range. The document also provides details on power distribution, PCI interrupts, arbitration, and where to find additional documentation and technical support.