Memory Mapping - HP 9020 Service Manual

2-16
Theory of Operation
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CHIP SELECTS
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,8
MEMORY ADDRESS BUS
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RAM RAM
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RAM
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4 .......
RAM RAM
TO
MPB
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32
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,
MEMORY
CONTROLLER
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RAM RAM
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RAM RAM
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RAM RAM
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16K X 8
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RAM RAM
Figure 2-8. 256K RAM Finstrate Block Diagram
Memory Mapping
,7
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RAM
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RAM
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RAM
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RAM
The Memory Controller has a memory mapping capability which provides a translation of logical
addresses on the MPB to physical addresses in RAM. Mapping memory addresses from the logical
address space of the MPB to the physical address space of the memory itself allows each MC to
respond to only those addresses of memory under its control. It also allows logical addresses to be
independent of physical addresses. The MC has 32 mapper CAM registers. Each register is associ-
ated with one 4K block of RAM.