TM 5-6675-323-14
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
SYNC
A synchronizing signal generated by the
SYNCHRONOUS
microprocessor denotes when microprocessor
is in an instruction fetch cycle.
STM
A signal generated by the microprocessor
START MEMORY
which is essentially the system timing
signal.
The signal's leading edge indi-
cates that there is a stable address on the
bus.
When the signal is true, it indicates
a memory reference is in process.
UMC
A handshake signal indicating that a memory
UNSYNCHRONOUS
or a register is ready to process data.
MEMORY COMPLETE
A signal generated
by the microprocessor
SMC
SYNCHRONOUS
when data, or an
instruction, is on the
MEMORY COMPLETE
bus . T h e t r a i l i n g
edge indicates that the
microprocessor has
accepted data. UMC must
b e present for the
microprocessor to gener-
ate SMC.
PDR
PROCESSOR DRIVING
A signal generated by the microprocessor
denotes when the microprocessor is driving
the MOS bus.
A microprocessor generated signal indicating
RD
READ
when memory is in a READ/WRITE state.
A microprocessor generated signal to decode
RAL
REGISTER ACCESS LINE
registers 20-27.
A power-up signal to the microprocessor.
POWER ON
PON
B e g i n s program execution at 40 8 .
A signal from the interpolator section sig-
INT
INTERRUPT
nifying it is ready to receive new velocity
T h e INT signal forces the micro-
data.
processor to execute "JSM10,I" instruction.
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