Advertisement
FUNCTIONAL DESCRIPTION
The IMS AI RAM 4A board provides up to 4K bytes of static
random access memory.
2102-style memory chips that each have the capacity to
store 1024 words of one bit for each word.
chips are used to store one block of 1024 eight-bit words.
Up to four sets of eight-chip units can be used on the
board, giving a maximum capacity of 4096 eight-bit words.
Each eight-chip unit has the circuitry to allow or prevent
the ability to write information into their memory storage
space.
This "write-protect" feature can be controlled
either by software commands or from the computer front
panel.
Software commands can both affect the write pro
tect and test the status of the write protect.
program attempts to write into a write-protect block of
memory, an interrupt will be generated.
may be disabled if desired.)
to indicate the protect status of each of the IK blocks
of memory.
Four green LE D 's are also provided which illu
minate when their respective block of memory is addressed.
The RAM 4A board will support a front panel write protect
switch.
If the machine is stopped, the 1024 word block
at which the machine address is pointing will have its
memory write protect status affected through the use of
a PROTECT/UNPROTECT switch on the front panel.
to write into this section of the memory will, of course,
not succeed.
The RAM 4A board is designed to allow the user to provide
battery backup power.
allow the battery to be charged while the computer is
running may also be installed on the board by the user.
The 8080A microprocessor can address up to 65,536 words
of memory, thus allowing up to 16 4096 word RAM 4A-4
boards to be installed in one IMSAI 8080 system.
(Additional memory can be accessed by using IMSAI's
Shared Memory Facility.)
RAM 4A BOARD
The board is implemented with
Four red LED's are provided
Trickle-charging facilities to
Thus eight
If the
(This feature
Attempts
6 - 1
Advertisement
