Processor Board; Overview; Central Processing Unit - HP 340 Series Service Manual

Processor Board
Overview
A variety of CPU, Inernory, and interface circuits reside on the processor board. Circuits include:
• MC68030 CPU at 16.67 MHz.
• MC68882 Floating-Point Coprocessor.
• RAM controller.
• HP--IB (IEEE-488) Interface with two-channel DMA controller.
• RS-2:32C Serial Interface with DB25 connector.
• HP--HIL Interface.
Central Processing Unit
A Motorola MC68030 CPU is used. Its synchronous data bus is 32-bits wide for both addresses
and data registers. The MC68030 CPU can address 4 Gbytes of RAM. Operating at 16.67 MHz,
it is significantly faster than many workstation CPUs.
The CPU has 57 instruction types and handles 7 major data types. It also has 18 addressing
modes, 6maskable and 1 non-maskable interrupt levels. Six stack frames exist in the MC68030.
At power--up, the CPU executes instructions from the Boot ROMs to determine the presence
of video circuits. Data in the video board's ID /FONT ROM is placed in a display controller
register to set the display clock frequency.
Figure 3-4. Processor Board
Functional Description
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