MC912DG128A Motorola, MC912DG128A Datasheet - Page 399

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

subroutine — A sequence of instructions to be used more than once in the course of a program.
synchronous — Refers to logic circuits and operations that are synchronized by a common
timer — A module used to relate events in a system to a point in time.
toggle — To change the state of an output from a logic 0 to a logic 1 or from a logic 1 to a logic 0.
tracking mode — A mode of PLL operation with narrow loop bandwidth. Also see ‘acquisition
two’s complement — A means of performing binary subtraction using addition techniques. The
unbuffered — Utilizes only one register for data; new data overwrites current data.
unimplemented memory location — A memory location that is not used. Writing to an
variable — A value that changes during the course of program execution.
VCO — See "voltage-controlled oscillator."
vector — A memory location that contains the address of the beginning of a subroutine written
voltage-controlled oscillator (VCO) — A circuit that produces an oscillating output signal of a
waveform — A graphical representation in which the amplitude of a wave is plotted against time.
wired-OR — Connection of circuit outputs so that if any output is high, the connection point is
word — A set of two bytes (16 bits).
write — The transfer of a byte of data from the CPU to a memory location.
MOTOROLA
The last instruction in a subroutine is a return from subroutine (RTS) instruction. At each
place in the main program where the subroutine instructions are needed, a jump or branch
to subroutine (JSR or BSR) instruction is used to call the subroutine. The CPU leaves the
flow of the main program to execute the instructions in the subroutine. When the RTS
instruction is executed, the CPU returns to the main program where it left off.
reference signal.
mode.’
most significant bit of a two’s complement number indicates the sign of the number (1
indicates negative). The two’s complement negative of a number is obtained by inverting
each bit in the number and then adding 1 to the result.
unimplemented location has no effect. Reading an unimplemented location returns an
unpredictable value.
to service an interrupt or reset.
frequency that is controlled by a dc voltage applied to a control input.
high.
Glossary
MC68HC912DT128A Rev 1.0
Glossary
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