Lexicon MPX-1 User Manual

INTElUlUPT "CALL" JUMPERS
The MPX-1 "calls" the system CPU by causing an interrupt on the bU:;l. There
are ten possible interrupt lines that the MPX-1 may assert. They are: INT*,
NMI* or any of the eight vectored interrupt lines (VIO*-VI7*). There are also
two methods by which the MPX-1 can assert the interrupt request - the SOD line
or by setting a hardware latch (described above in the section entitled "Getting
the Main System CPU's Attention").
The interrupt line asserted and the method of asserting it are selected by
Jumpers J1-10. These jumpers are implemented with push-on shorting plugs and
pins soldered into the board. Each jumper has three pins labeled A, B andC.
The "A" pin of each jumper is connected to the SOD interrupt source. The "c"
pin of each jumper is connected to the interrupt response latch. The "B" pin of
each jumper is connected to an interrupt line on the bus according to the chart
below:
JUMPER
/1 LEGEND MARKING
"B"
POSITION CONNECTION
1
7 VI7*
2 6 VI6*
3 5 VI5*
4 4
VI4*
5
3
VI3*
6 2
VI2*
7
1
VIl*
8 a VIa*
9
NMI NMI*
10
INT
INT*
EXAMPLE: To connect the MPX-1 interrupt request output to the INT* line on the
bus with the interrupt source' from the SOD line, a shorting plug should be
installed at J1a from the "A" to "B" position (left of center).
EXAMPLE: To connect the MPX-1 interrupt request output to the VI3* line on the
bus with the interrupt source from the interrupt latch, a shorting plug should
be installed at J5 from the "B" to "c" position (right of center).
NOTE: The software supplied with the MPX-1 assumes the use of the SOD interrupt
mode, so if you wish to use the MPX in an interrupt driven mode with the
standard software, use only the SOD interrupt source.
SELECTING AND USING 4K OR 16K RAM. CHIPS
The MPX-1 can use either 2147 4Kxl RAM chips, or 2167 16Kx1 RAM chips. The
MPX-1 should have come from the factory already jumpered correctly for the type
of chip that was originally ordered with the board. Should it become necessary
to change these jumpers once the board is in the field, here is how different
RAMs are jumpered and inserted:
USING 2147 4Kxl TYPE BAM CHIPS
To use 2147 type RAM chips, jumpers J11 through J17 should be installed and
J18 should be open. Jl1 through J17 are located in-between the RAM array (U10-
10

Lexicon MPX-1 Specifications

General

Brand	Lexicon
Model	MPX-1
Category	Recording Equipment
Language	English