HRAM
USER/TECHNICAL
MANUAL
3.1.3
EXAMPLE 3: FOUR BANKS
In this example, the HORIZON contains one 32K HRAM
board,
thr.ee
48K HRAM boards and a standard Micro-
Disk Controller at E8OOH. All HRAM boards are revision
E. The switches and jumper plugs for this example are
shown in Figure 3-4.
Only the lower half (OOOOH through 3FFFH) of the 32K
board is used. An operating system is loaded into this
half and it is always turned on.
All three 48K boards have their memory between 4000H
and FFFFH, except for the 2K section E800H through
EFFFH which must be disabled to prevent interference
with the Micro-Disk Controller.
The three 48K boards constitute three banks which are
switched as single units. One of these banks (board 2)
is programmed to switch on when the system is powered
up or reset, and the other two are programmed to
switch off when the system is powered up or reset.
Parity checking is left in the standard North Star
configuration.
Summary of Contents for HORIZON Random Access Memory
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