KA46 System Board Specification

This document is the "KA46 System Board Specification" (Order Number KA46-0-DBF, Revision X.02, dated October 10, 1990) for the KA46 system board, which is the central component of the Digital Equipment Corporation VS4000-400 desktop workstation.

The specification details the functional characteristics and major hardware components of the KA46 system board. Key elements described include:

• Central Processor: The KA46 utilizes the DC595 processor chip (MicroVAX), supporting a subset of the VAX instruction set with 30-bit physical addressing, along with a DC598 Clock Chip and DC596 Floating Point Accelerator.
• Memory: It features an 8-104 MB RAM main memory with parity checking, a 256 KB second-level write-through cache, and ROM memory for system boot, diagnostics, and network addressing.

• Integrated Controllers: The board includes controllers for:

  • Four asynchronous serial ports (for keyboard, mouse/tablet, printer, and general communications).
  • A single asynchronous/synchronous SCSI port for storage.
  • A bitmap display controller (requiring external video modules).
  • A ThinWire or Transceiver Ethernet network.
  • Audio I/O.
  • A time-of-year clock.

• System Architecture: It relies on custom Gate Arrays (DC7203, DC7201) for cache, I/O, and memory management.

• Operational Details: The document also covers internal processor registers, memory management, interrupt handling, DMA operations, and provides detailed pinouts for various connectors on the system board.