Model 961 256 K Dynamic Ram Board - IMS 5000 Series Manual

2.5.2 MODEL 961 - 256 K pYNAMIC RAM BOARD
GENERAL PESCRIPTION
The Model 961 Memory Board uses 64K X 1 bit dynamic memory circuits.
Boards are tested and burned in at an devated temperature under diagnostic test
to insure rdiable operation.
A standard feature of the 961 board is byte parity checking which can generate an
Interrupt or a Wait signal to the CPU if any single bit memory error occurs. A
LED indicator on the board lights up to indicate an error. The CPU can then
read the memory board's I/O port to clear the error indicator.
The Model 961 board has a "Phantom Signal" input for systems with ROM
memories which use this feature. The phantom signal, when active, disables all
memory except the Initial Program Loader ROM.
The 961 board decodes a full lO-bit address, allowing a system memory address
capacity of 1 Megabyte.
Switches allow the system to address the board as a
256K memory segment.
CONFIGURING THE 961 BOARP
Memory Board Address Select OM
Since there is a system memory capability of 1 megabyte, a 971 memory board
can be used to supply a 256K segment of memory. Shunt JA is the segment
sdect shunt, identifying which addresses the board will respond to.
JA-l
JA-2
JA-3
JA-4
shunted
shunted
shunted
shunted
=
addresses
=
addresses
=
addresses
=
addresses
00000-3FFFF
40000-7FFFF
80000-BFFFF
COOOO-FFFFF
Parity Error Response Selection OB)
Shunt J B sdects the type of response the CPU will give to a parity error.
JB-1
shunted
=
VII (Vectored Interrupt 1)
JB-2
shunted
=
VI2 (Vectored Interrupt 2)
JB-3
shunted
=
VI3 (Vectored Interrupt 3)
JB-4 shunted
=
VI4 (Vectored Interrupt 4)
JB-5
shunted
=
VIS (Vectored Interrupt 5)
JB-6
shunted
=
VI6 (Vectored Interrupt 6)
JB-7
shunted
=
NMI (Non-Maskable Interrupt)
JB-8
shunted
=
ROY (Hold CPU in a wait condition)
The state of the parity circuit may be sensed by reading the I/O port on the
memory board.
If bit 0 contains a "1", a parity error has occurred.
The normal setting depends on the operating system used.
IMS International
5000 Series Microcomputers/7.01.83jPage 31