TM 5-6675-318-14
r . Main PCA A2 processor circuitry. The plotter microprocessor is a 16-bit word
controller which essentially accesses and processes instructions from memory. It
also performs mathematical operations and controls the flow of data on the plotter
bus.
The microprocessor circuitry also contains a clock generator, memory timing
and decoding circuits, bidirectional drivers, register decoders, and interrupt and
self test registers.
Refer to Table 3-14 for microprocessor definitions.
Table 3-14. MICROPROCESSOR DEFINITIONS
Definition
Name
Mnemonic
A synchronizing signal generated by the
SYNCHRONOUS
SYNC
microprocessor denotes when microprocessor
is in an instruction fetch cycle.
A signal generated by the microprocessor
START MEMORY
STM
which is essentially the system timing
s i g n a l . The signal's leading edge indi-
cates that there is a stable address on the
When the signal is true, it indicates
bus.
a memory reference is in process.
A handshake signal indicating that a memory
UNSYNCHRONOUS
UMC
MEMORY COMPLETE
or a register is ready to process data.
SMC
SYNCHRONOUS
A signal generated
by the microprocessor
MEMORY COMPLETE
when data, or an
instruction, is on the
The trailing
edge indicates that the
bus.
m i c r o p r o c e s s o r has
accepted data. UMC must
b e present for the
microprocessor to gener-
ate SMC.
A signal generated by the microprocessor
PROCESSOR DRIVING
PDR
denotes when the microprocessor is driving
the MOS bus.
READ
A microprocessor generated siqnal indicating
RD
when memory is in a READ/WRITE state.
REGISTER ACCESS LINE
A microprocessor generated signal to decode
RAL
registers 20-27.
POWER ON
A power-up signal to the microprocessor.
PON
B e g i n s program execution at 40 8 .
A signal from the interpolator section sig-
INTERRUPT
INT
nifying it is ready to receive new velocity
d a t a . T h e INT signal forces the micro-
p r o c e s s o r t o e x e c u t e " J S M 1 0 , In i n s t r u c t i o n .
3-125
